Understanding of living phenomena on the basis of chemical concept has made a remarkable development in past two decades, and so many purely synthetic molecules have been found in these several years which successfully show their "molecular recognition" capacities. Here, various possible and promising approaches to chemical organization for the artificial living systems will be discussed. In chapter 2, prepa ration of artificial cells will be discussed, with attention focused on lipid-lipid interaction in the membrane of liposomes, formation of the pH gradient across the membrane in the artificial respiratory cell and the artificial photosynthesis system. Chapter 3 summarizes the chemical organization of artificial enzymes and artificial re ceptors by the use of cyclodextrin, cyclophanes or crown ethers. Purther, development of the artificial P-450 model system will be discussed. "Allosterism" proposed by Monod as a unique and most beautiful concept for regulation, for example, has become more and more important since more and more allosteric enzymes have been discovered, many of which are membrane-bound. The basic characteristic of the allosteric regulation is the transfer of the conformation change of the protein to the rest proteins in a single protein-protein complex. We have succeeded in chemical organization for "allosterism" by the use of "gable porphyrin". Emphasis is placed on this system in chapter 4.

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Lipophilic bis(monoaza-12-crown-4) [1a], bis (monoaza-15-crown-5) [1b], bis (12-crown4) [2], and corresponding monocyclic monoazacrown ethers [3a] and [3b] were applied to neutral carriers of ion-selective electrodes for sodium and potassium ions. The potential response of these electrodes towards sodium and potassium ions were found to be dependent on pH of the solution. The ion-selective electrodes based on [1a] and [1b] showed Nernstian or near-Nernstian response in wide activity ranges of the metal ions in the solution of high pH, showing prominent selectivities for sodium and potassium ions, respectively (k^Pot_NaK for [1a] electrode: 8.9 x1O^-3, k^PotKNa. for [1b] electrode: 9.1 x 10^-3, at pH 13). The bis(monoaza crown ether)s are superior to the corresponding monocyclic analogs, [3a] and [3b], significantly as the neutral carriers of the sodium and potassium ion-selective electrodes. In spite of the similar bis(crown ether) structure, [2] is inferior to [1a] in the sodium selectivity. The excellent sodium selectivity of the electrode based on [1a] was not affected much by the parameter of ion-selective membrane such as variation of plasticizer, neutral carrier concentration, and addition of lipophilic salt.

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A new methoxy-sufolitated crown ether spin-labeled with t-butyl nitroxide radical moiety was prepared, and the 96% pure radical crystal was successfully isolated. The nitroxide crown ether shows a pronounced solubility both in water and in nonpolar organic solvent. The distribution parameters between aqueous and organic layer were evaluated on the basis of measurements of ESR signal intensity. An excellent linear relationship was seen in the plot of observed distribution parameters vs 1/ε', values of organic layer. By taking into account the distribution of nitroxide crown ether into the aqueous layer, the extraction constants of potassium picrate were calculated as a function of the potassium picrate concentration detected in the organic layer. The potassium picrate extraction constant of nitroxide CR is remarkably improved by its pronounced hydrophilicity.

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[16]aneN₅ with the polyether chain (L₂) and a or the dieter of [16]aneN₅, with the polyether bridge (L₃) were synthesized, and the solubility of calcium phosphate, calcium oxalate, and urinary calculus in the presence of L₂, L₃, or EDTA was evaluated by an atomic absorption method. The results indicated that L₂ and L₃, especially had high solubilizing ability in an acidic region.

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Heptakis(6-alkylthio-6-deoxy-2-0-sulfo)-β-cyclodextrins have been synthesized by selective modification of β-cyclodextrin (β-CD), as a novel class of anionic cylindrical surfactants. The inclusion function of these surfactants was studied in water by using fluorescent probes as the guests. It was found that the binding ability of these surfactants for a neutral probe (PNA) was more than ten-fold stronger than that of β-CD, but it seemed to be independent of molecular aggregation of a surfactant monomer. Inclusion appears to occur at the inside of a hydrophobic cavity undergoing strong influence of electrostatic effect by anionic su lfate groups and the effect of chain length of alkylthio groups.

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Pure 6A6B-, 6A6C-, and 6A6D-Bis(naphthylsulfonyloxy)-β-cyclodextrins were prepared and isolated. Association constants between the disubstituted β-cyclodextrin and sodium ladamantanecarboxylate or l-adamanthylammonium chloride were measured from the guestinduced change of the fluorescence and circular dichroism spectra of the disubstituted cyclodextrins. The association constant of the 6A6C isomer was three-fold larger than those of the 6A6B and 6A6D isomers. The guest-binding of the disubstituted cyclodextrins caused the decrease in the fluorescence intensities and the appearance of the excimer emission. Also, the guest-binding changed the dichroism spectra dramatically, demonstrating the change of the relative position of the two naphthyl groups. These spectral changes were dependent on the regiochemistry (6A6B, 6A6C or 6A6D) of two substituents of the cyclodextrins. These spectral change and the association constants suggested that a naphthyl group partially included in the β-cyclodextrin cavity moved to the outside of the cavity to interact with another naphthyl group which was located out of the cavity.

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The interaction of cyclodextrins (CDs) with lipid membrane was investigated in terms of the leakage of marker compound, calcein, entrapped in inner aqueous phase of liposome, and the time course of surface pressure of monolayer of lecithin or cholesterol in the presence of aqueous CD solutions. The surflace pressure of monolayer of lecithin spread on CD solution decreases in the order, α->β->γ-CD, while that of cholesterol lies in the order, β->γ->α-CD. The leakage of entrapped calcein lies in the order Di-O-methyl-β->α->β->Tri-O-methyl-β->γ-CD for the liposome composed of 83 molar percent egg yolk lecithin and 17 molar percent dihexadecylphosphate. While the leakage of calcein lies in the order Di-Omethyl-β->β->α->γ->Tri-O-methyl-β-CD for the liposome composed of equimolar mixture of egg yolk lecithin and cholesterol, and 17 molar percent dihexadecylphosphate. Judging from the above results, CD molecules recognize the lipid molecule in membrane by virtue of their cavity size for nonmethylated CD, and the cavity size and the hydrophobic character for methylated CDs. Then, they pull out the lipid molecules by forming the inclusion complex, resulting in the destruction of membrance structure.

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The Co(III) complex containing an optically active cyclen, (2R, 5R, 8R, 11R)-2, 5, 8, 11tetraethyl-I, 4, 7, 10-tetraazacyclododecane, reacts with a-amino-a-methylmalonic acid (AMM)to give the title compound as the sole product. The molecular structure of the complex was determined by X-ray analysis. Crystal data were monoclinic, space group P21, a=13.985(6), b=11.768 (13), c=9.626 (3) A, β= 108.36 ( 3 )°, U=1504 (2)A3, and Z=2. Least-squares refinement converged at R=0.055 for 2977 unique reflections. The complex revealed a cis-octahedral geometry with the macrocycle coordinated in folded manner, and the chiralities of four nitrogen atoms of the macrocycle were S, S, S, R as found in the starting complex (Fig, 3). The AMM coordinates to Co(III) by the pro R carboxylate and the amino group in β form with δ conformation, and the absolute configuration of the chiral center in the AMM moiety is R. The uncoordinated carboxyl group forms an intramolecular hydrogen bond to one of the nitrogens in the cyclen ligand. Thus the starting complex recognizes the prochiral center in AMM through three-point attachment. Decarboxylation of the AMM complex resulted in the formation of alaninato complexes, whose R:S ratio was 28:72. The cycle of asymmetric synthesis of alanine was performed under mild reaction conditions by the releasing alanine from the alaninato complex and by recovering the complex as the starting compound [1] (Fig.6).

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Both _D-glucose (_D-Glc) and _D-mannose (_D-Man) reacted with nickel(II)-tmen complex, [Ni(H₂O)₂(tmen)₂]Cl₂ (tmen =1-dimethylamino-2-(methylamino)ethane) to give the identical green complex [3], containing only _D-mannose as a sugar component. In order to elucidate the factor that caused the stereoselective uptake of one of the two C-2 epimeric aldoses by nickel(II) complexes, we have investigated the nickel(II) complexes containing N-glycosides by means of EXAFS (Extended X-ray Absorption Fine Structure) spectroscopy. X-Ray absorption measurements were carried out with a laboratory EXAFS system for the samples. (a) nickel foil, (b) [Ni(_L-Rha-tn)₂]₂₊ [I], (c) nickel binuclear complex [2], μ-Man-[Ni₂(CH₃OH)(N-(_D-Man)-dmen) (N, N'-(_D-Man)₂-dmen)]²⁺ and (d) complex [3](unknown sample). The results of the present EXAFS study show that the complex [3]has a nickel polynuclear structure involving the N-mannofuranoside bridging. In addition, it is assumed that the coordination ability of the N-mannofuranoside bridging brings about the stereoselective complexation.

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[Ni(R, R- or S, S- chxn)2]Br₂.3 H₂0(abbreviated to [R, R] or [S, S]) reacts with certain aldoses in methanol to yield octahedral Ni(II) paramagnetic complexes [Ni(aldose-chxn)₂]Br₂containing two N-glycosides, where chxn is 1, 2-cyclohexanediamine. This reaction is sensitive to the absolute configuration on C2 of aldoses. In most cases, [R, R] reacts preferentially with aldoses having S configuration on their C2 atom, and [S, S] with corresponding C2-epimer having R configuration. Aldoses are easily recovered from the complexes by the treatment of slightly acidic aqueous solutions. Therefore, this reaction can be utilized for molecular recognition and separation of certain sugars. The 1:1 mixture of _D-glucose and _D-mannose which are mutual C2-epimers reacted with [R, R] in methanol to yield blue complex which contained only _D-mannose. In other cases there occurred partial separation in a mixture of C2-epimers. This selectivity was discussed in terms of the stereochemical features of these complexes. As previously observed in N-glycoside complexes derived from en or tn (en=ethylenediamine, tn=trimethylenediamine), these N-glycosides which have been derived from chxn is also expected to coordinate with a Ni(II) ion stably as a tridentate ligand in meridional form. When the coordination was achieved in meridional form, these tridentate ligands containing two five-membered chelate rings linked with a glycoside nitrogen, will take its most stable form in such a way as one chelate ring is δ-gauche, and the other is λ. These stereochemical features seem to be very important to the molecular recognition of aldoses.

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To obtain information of the driving force of intramolecular aromatic ring stacking in ternary Cu(II) complexes, the effects of ring-substituted hydroxyl and nitro groups on stabilization due to stacking interactions have been investigated by potentiometric and spectroscopic methods for Cu(II)(DA)(_L-AA) where DA =2, 2'-bipyridine, 1, 10-phenanthroline, 5-nitrophenanthroline, histamine, 2-(aminomethyl)pyridine, or ethylenediamine and AA=phenylalanine, tyrosine, p-nitrophenylalanine, tryptophan, 5-hydroxytryptophan 6-nitrotryptophan, alanine, or valine. Strong charge transfer bands at 350-450 nm in the difference spectra and circular dichroism (CD) spectral magnitude enhancements in the d-d, region were observed for the systems involving aromatic DA and AA and ascribed to the stacking interactions. The stability constants log βpqrs for Cu_p(DA)_q(AA)_r(H)_s were determined at 25°C and I=0.1 mol.dm (KNO₃). The stabilization due to intramolecular stacking was evaluated by calculating the constants K for the hypothetical equilibrium from the log βpqrs values obtained: Cu(DA)(_L-ala)+Cu(en)(_L-AA)_??_Cu(DA)(_L-AA)+Cu(en)(_L-ala)where ala=alanine and en=ethylenediamine. The nitro group in p-nitrophenylalanine contributes to the stacking with the imidazole ring of histamine, while that in 5-nitrophen, anthroline stabilizes with tryptophan. The CD magnitudes were found to be quantitatively related to the populations of the stacked species calculated from the log K values. The Cu(II)-aromatic ring interaction is not an important factor for the stabilization of the stac ked form. The stability enhancements due to the nitro group indicate that charge transfer due to the electron density difference plays an important role in specific stacking interactions. The structure-stability relationship was, discussed from possible charge, transfer modulated by ring substituents and the central metal ion.

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_L-α-Dimethylamino-ε-caprolactam, a seven-membered cyclic amide, was examined as catalyst for the asymmetric addition of hydrogen cyanide to aldehyde to form cyanohydrin. Optical yield of 5-30% was obtained when aliphatic aldehydes were used as substrate. For example, when isobutyraldehyde was used, optical yield of 26.3% was obtained. By using cyclo (_L-Phe-_L-His) or _L-α-dimethylamino-ε-caprolactam as catalyst, the first example of asymmetric transcyanohydrination between an aldehyde and acetone cyanohydrin was achieved. With isobutyraldehyde as substrate and cyclo(_L-Phe-_L-His) as catalyst, high optical yield of 62.7 % was obtained.

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It is theoretically possible, by utilizing biological stereoselectivities toward meso or prochiral molecules, to transform the starting material into the optically active compound quan titatively. To develop this useful methodology for asymmetric syntheses, we attempted a microbiological transformation of a symmetrical diketone, 8a-methyl-cis-2, 7-decalindione [4], into a chiral ketol. Incubation of [4] with Rhodotorula rubra gave a mixture of two diastereomeric ketols in a ratio of 4:1, Acetylation of the metabolite followed by chromatography afforded keto acetates [6] and [8] which were hydrolyzed to furnish (+)-ketol 5 (54% yield, mp 67-68°C, [α]_D²⁵ +12.3°, 88% optical purity) as a major product and (-)-ketol [7] (13%yield, mp 99-100°C, [α]_D²⁵ -45.4°, 93% optical purity) as a minor product. The chemical conversion of (-)-ketol [7] to (+)-6-methyl-4-t wistanone [10] with (R)-framework (mp 133-135°C, [α]²²_D, +300°), via keto mesylate [9], gave information on the stereochemistry of (-)-ketol [7] as being (4aR, 7S, 8aS)-configuration. For inversion of the configuration at C-7, (+)-ketol [5] was converted to keto tosylate [16] and was treated with KNO2, in DMSO to afford (+)-ketol ([α]_D²⁰ +43.1°) which was found to be an enantiomer of (-)-ketol [7]. Thus, the absolute configuration of (+)ketol [5] was determined as being (4aS, 7S, 8aR). These results clearly show that R. rubra prefe rentially catches the pro-S group of two enantiotopic carbonyl groups on the diketone [4], and the hydrogen attack occurs from the Re-face of the carbonyl plane. The Wolff-Kishner re duction of (+)-ketone [10] gave (+)-1-methylwistane [11] (mp 113-114°C, [α]_D²² +399°, 93% optical purity). Thus, a. microbiological reduction cou pled with a chemical conversion provided a convenient synthetic route to a cage-shaped hydrocarbon [11] with high optical purity.

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The biocatalyst electrodes, that is, the oxidoreductase-immobilized electrodes in which the electrode behaves as a substitute for a chemical electron acceptor or donor of oxidoreductase reaction could be used in such novel applications as biosensors, bioreactors and biofuel cells. The presence of an electron-transfer mediator between the electrode and the enzyme is useful to accelerate the electrocatalysis at the electrode. Mathematical analysis of the diffusion coupled with the enzyme reaction of both substrate and mediators in the immobilized enzyme layer on the electrode surface has revealed important parameters for understanding the process at the biocatalyst electrode with electron-transfer mediator. The apparent enzyme rate constant and Michaelis constants to characterize the bioelectrocatalysis at the electrode was defined and discussed. Also, the collection factor, that is, the ratio of the amount of mediator collected by the electrode to the total amount of mediator produced in the enzyme layer was defined and discussed. The current-potential curve was derived. A film-coated glucose oxidase (GOD)-immobilized gold minigrid electrode with p-bezoquinone-mixed paste and a film-coated GOD-immobilized platinum mesh electrode with oxygen permeable membrane were designed. These GOD electrodes worked satisfactorily as biocatalyst electrode to oxidize _D-glucose electrocatalytically. Characteristics of the GOD electrode with mediator for electrochemical conversion of _D-glucose to _D-gluconate were studied in terms of the current density and the electrode potential of the electrode. Use of biocatalyst electrodes in organic syntheses was discussed.

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As a type of interaction of neurotransmitters with a charged surface, adsorption of nine neurotransmitters. onto a gold electrode has been studied by measuring specular reflecti vity in phosphate buffer (pH 6.9). The neurotransmitters examined are: (a), γ-aminobutyric acid, glycine, β-alanine, dopamine, norepinephrine, epinephrine and (b), acetylcholine, glutamic acid, aspartic acid. All of these neurotrans mitters are adsorbed in the potential range around the point of zero charge. However, the difference in the potential dependence of adsorption is clearly observed'between groups (a) and (b). The adsorption potential profiles obtained for group (a)are of a quasi-bell-type, indicating no orientational change takes place in their adsorptiondesorption processes. On the other, hand, group (b) exhibits rather complicated profiles, implying conformational changes in the adsorbed molecules may occur depending on the surface charge. Groups (a) and (b) are known to function as inhibitory and excitatory neurotransmitters, respectively, in central nervous system. Then the results suggest that electrosorption of neurotransmitters may provide a very simple model of their combinations at the receptor sites on synaptic membranes. In this paper, optical reflection method is reconfirmed to be useful to recognize the adsorbed molecules on the electrode surface, in situ, and to be promissing to develop the bioelectr ochemical applications.

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The intermolecular interactions between the optically active metal complexes adsorbed on colloidally dispersed clay particles sodium montmorilIonite have been investigated with electric dichroism and circular dichroism measurements. It was confirmed that the metal complexes interacted stereoselectively on a two-dimensional surface of the clay. During the process of interaction, optical activity was introduced into the chiral molecules. By use of an adduct of the clay-chelate, the asymmetric syntheses of optically active alkyl phenyl sulfoxides was accomplished.

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The high enantioselectivity has been obtained for the hydrolytic cleavage of p-nitrophenyl N-decanoyl-_D-(and _L-)phenylalaninate (C₁₂-_D(_L)-Phe-PNP) with N-benzyrloxylcarbonyl-_L-phenylalanyl-_L-histidyl-_L-leucine (Z-_L-Phe-_L-His-_L-Leu) in the micellar system (hexadecyltrimethylammonium chloride: CTACl). This would be attributed to the efficient intermolecular recognition between the _L-isomer substrate (C₁₂-_L-Phe-PNP) and the _LLL-tripeptide (Z-_L-Phe-_L-His-_L-Leu). So, we controlled the micellar reaction field by chaging the concentration and framework of surfactants in order to enhance the enantioselectivity for the hydrolysis of C₁₂-_D(_L)Phe-PNP with Z-_L-Phe-_L-His-_L-Leu. The noteworthy aspects are as follows: (a) The enantioselectivity is, markedly enhanced with an increase in the concentration of micelles and was kept constant above the critical micelle concentration. (b) the long alkyl-chain and head group in micellar surfactants take an important role to enhance the enantioselectivity. it is noteworthy that the highest enantiomer rate ratio (k^L_{a, obsd}/k^D_{a, obsd}) of 58 is observed in the presence of the (S)-(-)-SUR₁₆ micelles having both the C₁₆ alkyl chain and chiral had group. Furt hermore, in the co-aggregate systems composed of micelles (CTACl) and vesicles (dihexadecyldimethylammoniiim chloride: 2C₁₆N2C₁C1), it is of interest that the e nantioselectivity is maximized in the composition of 23 mol% CTACl/77 mol% 2C₁₆N2C₁Cl, and that the magnitude of enantioselectivity correlates with the hydrodynamic diameters of the co-aggregates.

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In the course of our study to verify the "similarity recognition hypothesis"the threedimensional shape similarity between interacting groups in reacting molecules is responsible for more specific and precise molecular recognition than would otherwise be achievedwe developed a parameter (S_I), which evaluates the three-dimensional shape similarity between a given substituent and the standard one. The two substituents in question, each being represented by the three-dimensional coordinates of its atoms and their van der Waals radii, are so arranged as to give a maximal overlap. Examination is made as to whether or not the points located with constant spacing are involved in the substituents (Fig.1). The S_I is defined as the ratio of the number of points involved in both of the substituents to that involved in either of them (Eq.5). Oxi dation of a pair of associating thiols ([1] and [2]) each with the recognition site (R¹ or R²) (Eq.1) gives one unsymmetrical [4] and two symmetrical disulfides ([3] and [5]). The selectivity (r, a measure of the degree of molecular recognition) is represented by the logarithmic ratio of the yield of the unsymmetrical disulfide [4] to twice that of the symmetrical disulfide [3] (Eq.6). The r values had good correlation with the S_I values for R¹=n-C₅H₁₁ and R²=i-C₆H₁₃, cyclo-C₆H₁₁, and Ph (Table 4), for R¹ =Ph and R²=cyclo-C₆H₁₁, i-C₆H₁₃, and n-C₆H₁₃ (Fig.4), and for R¹=n-C₄H₉ and R²=n-C_n H_2n+1 (n=2-6) (Fig.5). The selectivity neither depen ds on the difference in reactivity between the thiols ([1]and [2]) nor on solubility differences between the thiols. Furthermore, the order of the r values cannot be explained by the electronic, steric, or hydrophobic effect of the recognition site (R²). These findings support the "similarity recognition hypothesis" men-tioned above.

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Thermodynamic parameters of complex formation of tetranactin with various cations were estimated based on the analysis of IR and NMR spectra and on the calorimetric measurements. The sum of conformational energy of tetranactin-ion-complex and desolvation energy of the ion could elucidate the observed enthalpy of formation of tetranactin complex with alkaline metal ions. Since the oder of this enthalpy change for various ions coincided with that of the corresponding free energy change, enthalpy change might dominate the ion selectivity of tetranactin. In the case of small cation like Na⁺, or of divalent cation, the contribution of entropy of complex formation due to the desolvation of the ion was remarkable as compared with the cases of K⁺ and Rb⁺ ions. In the complex formation of tetranactin with NH₄⁺, the contribution of the enthalpy change was very eminent. This observation might be due to the fact that the mode of complex formation of NH₄⁺ ion is different from that of the other cations. It was concluded that ion selectivity of tetranactin can be determined both by conformational energy of tetranactinioncomplexed form and by desolvation energy of the ion, because desolvation energy of the ions is comparable with the conformational energy of tetranactin.

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Eu³⁺ and Tb³⁺ intercalations were studied on layered titanic acids. H₂Ti₃0₇, H₂Ti₄0₉. H₂0, and their alkylammonium complexes in aqueous chloride solutions. The lanthanoid ions were taken up into the alkylammonium complexes but were not detected in the products obtained directly from H₂Ti₃0₇ and H₂Ti₄0₉. H₂0. The interlayer alkylammonium ions were quantitatively exchanged with hydrated Eu³⁺ and Tb³⁺ ions during the reactions. The layered Eu titanate showed red luminescence under excitation at 400 nm and the Tb titanate emitted green luminescence by 380 nm excitation. The luminescence spectra of the Eu titanates are discussed in relation to the crystal structure of titanates.

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Solubility (30mg.cm-3) of α-cyclodextrin in water at pH7 and 30°C in the presence of the equimolar amount of adamantane-1-carboxylate [1] is much smaller than that (170mg.cm-3) in the absence of 1. In contrast, solubility of β-cyclodextrin (65mg.cm-3)in the presence of [1] is larger than that (21mg.cm-3) in the absence of 1. The enhancement of solubility of β-cyclodextrin by [1] is ascribed to the conformational change of β-cyclodextrin by the inclusion of bulky [1] into its cavity, which promotes the interactions between the hydroxyl groups of β-cyclodextrin and the solvent water molecules.

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The 400-MHz ¹H-NMR spectra of _L-isoleucine were measured in the presence of Escherichia coli isoleucyl-tRNA synthetase (IleRS). Because of chemical exchange of _L-isoleucine between the free state ang the IleRS-bound state, transferred nuclear Overhauser effect (TRNOE) was observed among proton resonances of _L-isoleucine. The IleRS-bound _L-isoleucine was found to take the gauche⁺ form about the C_α-C_β bond and the trans form about the C_β-C_γ1 bond. The TRNOE analysis is useful for studying the amino acid discrimination mechanism of aminoacyl-tRNA synthetases.

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Stereoselective hydrolysis of amino acid p-nitrophenyl esters was examined for poly (ethylenimine) derivatives with covalently-linked dipeptide containing a histidyl residue in the presence of copper(II) ions. Added copper(II) ions influenced both the rate constant and the ratio of stereoselectivity in the hydrolysis of the chiral esters by poly(ethylenimine)derivatives (I_a and I_b) depending on the nature of the esters and the modified polymers. Added copper(II) ions caused to increase the rate of the reaction, but no significant effect on the stereoselective preference for the quaternized polymer (I_b), indicating the action of copper(II) ions in the hydrolysis of the esters as catalyzed by a histidyl residue on the polymer.

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In membrane transport, recognition of transporting substrate is one of the most essential factors to promote its selectivity. Recognizing carrier incorporating membrane plays not only selective transport but active transport. A fundamental mechanism of the recognition and the transports are described with examples such as a selective and active transport of gallium ions with a non-fixed carrier membrane and that of alkali metal ions with a fixed carrier 'membranes. To develop a novel functionality of membrane using recognition phenomenon, preparations of functional molecule incorporating conducting polymers and their functionalities are also described. These functionalyzed conducting polymers provide us novel functionalities originated from incorporated specific functional molecule which selects functions.

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An octopus-like azacyclophane having four flexible hydrocarbon chains on the rigid macrocyclic skeleton, N, N', N'', N'''-tetrakis(10-carboxydecy1)-2, 11, 20, 29-tetraaza[3.3.3.3]paracyclophane-1, 12, 19, 30-tetraone (APC(C₁₀CO₂H)₄), was immobilized on the AF-amino Toyopearl 650 gel. The following hydrophobic guest molecules, whose binding behaviors toward APC(C₁₀CO₂H)₄ in homogeneous aqueous solutions have been clarified, were chosen for chromatographic separation. cationic Quinaldine Red and Rhodamine 6 G, anionic Methyl Orange and Orange I, and nonionic N-phenyl-1-naphthylamine and 1-(2-pyridylazo)-2naphthol. The chromatographic separation of these guest compounds was performed on the azacyclophane-bonded stationary phase by using eluants composed of methanol and aqueous carbonate buffer (0.01 mol.dm-3, pH 10.0, μ0.10 with KCl) at various ratios. The separation efficiency of the stationary phase is correlated with the inclusion ability of the octopus-like azacyclophane, which is primarily controlled by hydrophobic and electrostatic interactions between the host molecule and the guest molecules (Table 1 and Fig.3). When only one carboxyl group was exclusively bound to the AF-amino Toyopearl 650gel by protecting the rest of the carboxyl groups of APC(C₁₀CO₂H)₄ as the methyl esters, selective molecular recognition by the modified stationary phase was most enhanced relative to other modified ones which were prepared by direct immobilization of APC(C₁₀CO₂H)₄, on the Toyopearl gel.

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A ternary polymer/liquid crystal/photoresponsive crown ether composite membrane of several tens of nm in thickness was prepared by a water-cast method. A ternary composite thin film was prepared by building up several tens of layers of the water-cast composite membrane. Two types of photoresponsive crown ethers, AZO-CR (1) and AZO-CR(2) as shown in Fig.1 were used. The aggregation state of the composite membrane was investigated by transmission electron microscopic observation and DSC measurements. These measurements revealed that the liquid crystalline material formed a continuous phase interpenetrating with the spongy three-dimensional network of PVC. It was also confirmed that photoresponsive crown ether molecules were dispersed almost molecularly in liquid crystal domains. These results indicate that liquid crystal domains can play a role as a transporting phase for carriers and penetrants. The UV absorption measurements upon UV and VIS irradiations reveal that trans-cis photoisomerization of photoresponsive crown ether ocurred even in the ternary composite thin film. The photoresponsive facilitated transport of K⁺ through the polymer/liquid crystal/AZO-CR(1) composite thin film was investigated. Also, the active transport of K+ driven by photoirra. diation and pH gradient through the ternary composite thin film containing AZO-CR(2) was investigated.

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In the presence of Li⁺, Na⁺, and K⁺ ions, a competitive passive or active transport was carried out using a lipophilic monoaza crown ether picrate as the carrier in a dichloromethane liquid membrane. Both aqueous phases were adjusted to be basic and acidic, respectively. Octyl- and dodecyl-substituted monoaza 15-crown-5 were found to be excellent Na+ selective ionophores over Li⁺ and K⁺. On the other hand, monoaza 18-crown-6derivatives displayed a high K⁺/Na⁺ selectivity as expected. The transport velocity was almost the same between alkyl-substituted monoaza crown ether and N- pivot lariat ether. the cation selectivity decreased by the introduction of the secondary donating site. It should be noted that the leak of lipophilic anions could hardly be detected in the release phase. This finding strongly demonstrates that these carriers are corresponding to the crown ethers having a proton-ionizable group such as carboxylic-type ionophores. In addition, it is another merit that the presence of lipophilic anions works advantageously for aza crown ethers. The carrier used in this transport system is only required to possess the basic moiety as a structural unit, which participates in the complexation. From the viewpoint of the simplicity in the structure and its own transport mechanism, the development of new host molecules are expected.

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Optically ative, poly(triphenylmethyml ethacrylate) (PTrMA) was chemically bonded to silica gel by three, different methods and used as a chiral stationary phase for high-performance liquid chromatography. The most effective bonding was attained with a block copolymer of triphenylmetheyl methavry and 3-(trimethoxysilyl)propyl methacrylate. Chiral recogni-tion of PTrMA-bonded silica- gel, was similar to that of PTrMA-coated silica gel which we developed previously, _except for the difference caused by the different amount of polymer. The PTrMA-bonded silica gel was stable when tetrahydrofuran or chloroform was used. This made it possible to!resolve (±)-PTrMA and poly(diphenyl-2-pyridylmethylmethacrylate)into optical isomers. The stationary phase was also usable for gel permeation chro-matography.

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The chiral stationary phases, which involve chiral molecules, N-(2-naphthoyl)-_L-leucine and N-(3, 5-dinitrobenzoyl)-_D-phenylglycine, chemically bonded to 11-aminoundecylsilanized silica gel(long-chain spacer type CSP-1 and CSP-3, respectively), or to 3-aminopropylsilanized silica gel(CSP-2 and CSP-4, respectively), were prepared and the effect of the spacer length was investigated. N-acylamino acid butyl ester enantiomers were separated with better separation factors upon CSP-1 and CSP-3 than upon CSP-2 and CSP-4, respectively. For example, the separation factor for the enantiomers of N-(3, 5-dinitrobenzoyl)leucine is 2.18 upon CSP-1 as compared with 1.82 upon CSP-2, and the mixture of enantiomers of isoleucine and alloisoleucine derivatives was completely separated upon CSP-1. These results show the importance of the chain length of spacer. However, enantiomers of binaphthalenes were separated better upon CSP-4 than upon CSP-3. It is revealed that the separation mechanism of enantiomers in liquid chromatography is considerably complex.

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In order to separate the optical isomers of amino acids by permeation through a membrane, a polymer membrane having β-cyclodextrin moieties in the side chains was pre pared and the permeation characteristics of amino acids through the polymer membrane were investi-gated. When phenylalanine was permeated through the polymer membrane in water, the permeation rate of _L-isomer was greater than that of _D-isomer. The ratio of the permeation coefficient of _L-isomer to that of D-isomer was 1.4 0. A similar result was obtained in the case of tryptophan and histidine permeation. No difference in the permeation rat e between the optical isomers was observed with the polymer membrane having gluc ose instead of cyclodextrin moieties. It was found that the β-cyclodextrin moiety in teracts with _D-isorner more strongly than with _L-isomer through adsorption experiments of amino acids onto a cross-linked β-cyclodextrin gel. The diffusivity of _D-isomer in the mem brane was thus depressed by the interaction with the cyclodextrin moiety. The polymer membrane having β-cyclodextrin moieties can separate the optical isomers of phenylalanine and the _L/_D molar ratio, of phenylalanine permeated, was 61.7/38.3.

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Ultrafiltration performance of hycirogel membranes, prepared by the reaction of poly-(oxyethylene) and tris(4-isocyanatophenyl)-methane, was investigated. The state of water within membranes was studied by DSC and ¹H-NMR, which revealed the presence of two kinds of water, free, water. and nonfreezing water. These membranes gave relatively sharp molecular weight cutoff profile in ultrafiltration. Especially, membranes of poly(oxyethylene) network polymer, of which molecular weight of prepolymer was 20000, gave good membranes performance. This suggests that these membranes had possibility to be used as membranes for the hernofiliration.

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It was found that racemic cyanohydrins [2] are converted into one optically active isomer by complexation with brucine. For example, (±)-1-cyano-2, 2-dimethyl-1-phenyl-1-propanol [2a] was converted into 94%ee of (+)-[2a] in quantitative yield by complexation with brucine in, methanol. Similarly, optically active cyanohydrins, (+)-[2b](+)-[2c], (-)-[2d], (-)-[2e], (-)-[2m], (+)-[2p] and (-)-(2u) were obtained from correspond ing racemic cyanohydrins.

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Polystyrene-based adsorbents incorporating several poly(α-amino acid)s have been synthesized and evaluated for the resolution of (RS)-5-isopropylhydantoin in order to elucidate the effect of side chain length of the immobilized poly(α-amino acid)s on the resolution efficiency. Of the four adsorbents evaluated, poly(N5-benzyl-_L-glutamine)-incorporated adsorbent demonstrated the highest resolution efficiency, presumably in consequence of the most suitable size and the appropriate rigidity of the recognition site.

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A bioaffinity sensor which uses a molecular complex receptor of low affinity and an enzyme amplification has been developed for the determination of physiological and biomedical importances such as biotin (vitamin H), thyroxine (T₄), and insulin. A heterologous recognition type of bioaffinity sensor adopts a molecular complex receptor of membrane-bound determinant analogue and enzyme-labeled binding: protein or antibody. A homologous recognition one employs a molecular complex receptor of membrane-bound de terminant. The molecular complex receptor releases enzyme-labeled binding protein or antibody, when the sensor is in contact with a determinant in solution. Biotin is amperometrically determined in the concentration range of 10^-9-10^-7g.ml^-1 by heterologous recognition using 2-(4-hydroxyphenylazo)benzoic acid [HABA] or lipoic acid as a determinant analogue and avidin as a binding protein. A homologous recognition type of bioaffinity sensor for thyroxine (T₄) covers the range of 10^-8-10^-5 g.ml^-1. Insulin is optoelectronically determined in the range of 10^-8-10^-6g.ml^-1 by either homologous and heterologous recognition. Feasibility of bioaffinity sensors is discussed.

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A hydrogen gas sensor using s piezoelectric quartz crystal coated with thin palladium film has been developed for detection of small amounts of H₂ in inert gases. The principle of detection by a piezoelectric crystal is that the frequency of vibration of an oscillating crystal decreases with an increase in mass of a coating material on its surface. The gas is selectively adsorbed by a coating on the crystal surface, thereby increasing the mass on the crystal and decreasing the frequency. Sorption and desorption cycles of hy drogen were measured (Fig.2) and they exhibited, exponential curves (Fig.3). Frequency shift (ΔF), response and recovery time were calculated from the curves. This sensor showed relatively slow response at room temperature, however the frequency shift had a linear relation with the partial pressure of hydrogen (250-5000 ppm H₂ in N₂) at room temperature (Fig.4). Several parameters (flow rate, temperature and interferences of other gases) were investigated; no interferences were observed by the presence of CH₄, CO₂ and SO₂ contained as impurities in the inert gas and the. effect of flow rate was hardly observe (Figs.7 and 8).ΔF, response and recovery time were dependent on temperatur(25-100°C). they decreaseadt higher tempera-tures (Figs.5 and 6). Therefore, the effect of temperature was the trade-off between sensitivity and response or recovery time. At room temperature and a low concentration of hydrogen (250-5000ppm), the rates of sorption and desorptionp rocesseso f hydrogen in and from palladium film are expressed by first-order kinetics involving surface migration as proposed by Bucur et al. for high temperature(80°C) and higher H₂ concentration(2.O-70.9Torr) processes.

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The hetero-contacts of CuO/ZnO and NiO/ZnO are prepared by mechanically pressing both sintered pellets and the gas sensing characteristics of these hetero-contacts are investi-gated. When reducing gases were fed to the hetero-contact, the current across the interface increased in all cases (Fig.1). Very high sensitivity and selectivity for CO gas were observed by CuO/ZnO contact at 260°C under the applied voltage of +0.5 V (Fig.3). The gas sensitivity and selectivity were controlled by changing the applied voltage in both CuO/ZnO and NiO/ZnO (Figs.4, 6). The decrease in the contact potential (Table 1) and the increase in the capacitance at the junction (Figs.7-9) by the reducing gases were observed in these hetero-contacts. In addition, the current was increased by not only the reducing gases without oxygen in the carrier gas but also incombustible gas (CO2) (Fig.10). It is assumed from these experimental results that the increase in the cu rrent by the reducing gases is due to 1) the decrease in the potential barrier height at the junction by the desorption of chemisorbed oxygen or 2) the formation of a new channel for the current which flows through the interface states made of adsorbed molecules on the p-type semiconductor (Fig.11).

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A new type ion sensor, utilizing a change in the surface conductance caused by a change in the thfcicness of the pace charge layer (depletion layer), is described. The sensor comprises a semiconductor (n-Sn0₂)/ion-exchange polymer (Nafion) junction. The flatband potential, V_fb, of a bare Sn0₂ electrode was independent of the Fe³⁺ concentration in the solution. The Sn0₂ electrode coated with Nafipn, which was ion-exchanged to Fe³⁺type, showed a change in V_fb by 20 mV/decade. No pH dependence of V_fb was observed for this electrode. These results show that the band bending at the surface, V_s, and hence the thickness of the depletion layer, depend on the Fe³⁺ concentration in the solution. A relationship between the surface conductance change, Δσ_s, and V_s was derived as follows. where N_D is the donor density, ε is the, dielectric constant, μ₆. is the mobility of electrons, and e is the elementary charge. The conductance of the electrode at a constant potential changed with the Fe³⁺ concentration in the solution. The sensitivity of the sensor was higher at lower electrode potentials. When the electrode potential was below ca.0.4 V vs. V_AG/AGCl, the cathodicc urrent across the electrod surfacer reducing the Fe³⁺ ions was observed, which was also treated as the sensor signal.

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An uphill transport membrane sensor with a carrier impregnated thin nylon film was constructed. A nylon film was polymerized directly on top of an underlying mercury film electrode using the so-called surface polymerization technique. A small space (<50μl), filled with an appropriate solution, between an underlying mercury film electrode and the nylon film, was used as a receiving solution of membrane uphill transports (Fig.1). The nylon film thus prepared was impregnated with appropriate carriers dissolved in organic solvents. As an illustrative example, a Cd(II) ion uphill transport membrane sensor was demonstrated. The nylon film was impregnated with methyltrioctylammonium chloride and the uphill transport membrane sensor for Cd(II) ions was constructed as shown in Fig.2. This could amplify in itself the virtual concentration of Cd(II) ions by severa l ten times that of a sample solution. It should be noted that the remaining monomer (1, 6hexanediamine), after polymerization, which is dissolved in solution entrapped in a closed small space between an underlying electrode and the nylon film (see Fig.2), played another role in this case as a ligand for back extraction of Cd(II) ions at the inner surface of the nylon film membrane. The advantage of this nylon film approach is that the inner recieving solution can be made very small so that the amplification factor of the sensor increases accordingly (Table 1). Another possibility is that the response time would be shortened by reducing the nylon film thickness.

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Recently, the authors have reported spontaneous oscillations of electrical potential across a liquid membrane of nitrobenzene dissolving picric acid placed between two aqueous layers, one of which contained hexadecyltrimethylammonium, bromide (CTAB). The system produced rhythmic and sustained oscillations of electrical potential of 150 to 300 mV with time intervals of about one minute. As the extension of these studies, the authors investigated the behavior of a liquid membrane between two aqueous phases, one of which contained an anionic detergent in place of the cationic one. The present article shows that anionic detergent Also. generates rhythmic oscillations. Studies were made for a liquid membrane consisting of an oil layer, nitrobenzene containing 2, 2'-bipyridine, between two aqueous layers. one contains sodium. dodecyl sulfate C₁₂H₂₅0-SO₂-ONa (SDS) and the other contains 0.5 mol.dm_-3 sodium chloride. The system produced spontaneous oscillations of electrical potential. it was found that the amplitude and the oscillatory period was changed markedly by the concentration of alcohols added to the oil layer. The manner of response to alcohols in the liquid membrane with SDS was found to be greatly different from that observed in the liquid membrane with CTAB. The oscillations may be explained by the mechanism of consecutive formation and destruction of monolayer structures of the dodecyl sulfate anion at the interface between the oil and the aqueous phases. It is expected to develop a new type of chemical sensor which is capable to distinguish various chemical substances from the frequency, amplitude and shape of electrical oscillation that they induced.

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A new method was developed for preparing composite membranes consisting of an im-mobilized glucose oxidase membrane and a suporting membrane. The composite membrane were prepared by spin casting from a poly(_L-leucine-co-N-benzyloxycarbonyl-_L-lysine) solution in which glucose oxidase was dispersed, followed by spin casting from another polymer solution such as poly(4-methyl-1-pentene) or poly[1-(trimethyl-silyl)-1-peopyne]. The thickness of the thin enzyme membrane was 1 μm and 15-40 μm, respectively. A glucose sensor was constructed with an oxygen electrode and the composite membrane. The relationship between permeation rate of oxygen through these membranes and current decrease was studied. A response time was 25-30 s. A linear relationship was also obtained between the current decrease and the logarithm of glucose concentration in the range between 2.O×10^-1 and 1.8 x 10³ mg.l^-1. A minimum detectable concentration was 3.6×10^-2 mg.l^-1. The current decrease was reproducible after three months' usage.

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Glucose sensor, which can directly measure the blood glucose levels in the blood stream, was developed by having employed cellulose acetate membranes for the restriction of glucose penetration from the blood stream into the electrolyte of the oxygen cell. The semiperm eable properties of the membranes were controlled by the concentrations of cellulose acetate in the casting solutions and also by the thermal treatment between 60 and 90°C. The permeabilities of the membranes for glucose, P_m, were measured using a two compartments cell having a pair of synchronous propellers. The P_m for the suitable response of the sensor ranged in the order of 1×10_-6cm/s. These membranes worked well in the human plasma for 3 h. It might be appropriately used as the practical semipermeable membrane of the glucose sensor for the artificial pancreas.

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Dextranase is an important component for prevention of caries. A rapid and simple method is required for the determination of dextranase activity. An enzyme sensor consists of immobilized glucosidase and glucose oxidase membrane and an oxygen electrode. The sensor was applied to the determination of isomaltose. A steady current was obtained within 2 min. the determination range was 0.05-2 mmol.dm^-3. When dextran was added to the sensor system with dextranase, the decrease of output current was observed. The initial rate of current decrease was related to dextranase activity. Linear relationship was obtained in the range of 20 to 300 U/ml. Optimal pH and temperature were and 7, 35°C, respectively. Furthermore, the output current of the sensor remained almost constant for a month. The sensor was applied to preventive samples and satisfactory results were obtained (correlation coefficient, O.99). The determination time is reduced to less than one third the conventional method.

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Cyclic voltammograms of wild and antibiotic resistant cells were obtained by an electrode system with a basal plane pyrolytic graphite and a membrane filter to trap bacteria after the cells were incubated at 37°C for 1 h in the medium containing 50 μg/ml ampicillin or 20 μg/ml tetracycline. Wild and ampicillin or tetracycline resistant strains of E. colt were classified from the peak potential and shape of the cyclic voltammograms, when the potential of the graphite electrode was swept in the range from 0 to 1.0 V versus saturated calomel electrode (SCE). The peak current of wild strains decreased with increasing antibiotic concentration. On the other hand, the peak current of antibiotic resistant strains slightly decreased for ampicillin and almost constant for tetracycline. The peak current increased with increasing initial cell numbers. Consequently it was shown that cell number and minimal inhibitory concentration were estimated from the peak current of the cyclic voltammograms. Electrochemical reaction of CoA in the cell contributed to the classification of the wild and antibiotic resistant strains of E. coli. The minimal inhibitory concentrations obtained by the electrode system were almost in good agreement with those obtained by the conventional method.

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In order to determine cholesterol distribution in human serum lipoprotein classes, which has been known to be directly related to heart-attack deseases, a bioreactor-type detection system consisting of cholesterol ester hydrorase (CEH) and cholesterol oxidase (COD) immobilized on size-exclusion chromatographic gel (TSKgel G 6000 PW) was combined with size-exclusion chromatographic separation of the lipoproteins. Glass separation columns packed with G 5000 PW and G 3000 SW were found to be suitable for the separation. CEH and COD were coimmobilized on the gel activated with glutaraldehyde and packed into a glass column, which was connected to the exit of the separation column array. To the inlet of the enzyme column, introduced was staining fluid composed of peroxidase, 4-aminoantipyrine, N-ethyl-N-(2-hydroxy-3-sulfopropy1)-m-toluidine, and Triton X-100. In this system, cholesterol ester in the lipoproteins could be converted into cholestenone and subsequently thus released H₂0₂ could be stained in a Teflon reaction coil attached to the exit of the column. Upon using a polymer-coated pump, precisely controlled by the computer, and polymer parts to avoid stainless steel surface in the system, the peaks due to low density and high-density lipoproteins appeared in the chromatogram. The elution profile of the peaks was in good agreement with that obtained by the method reported previously in which a large amount of CEH and COD were consumed as staining reagents. From the elution volumes, the height equivalent to a theoretical plate number, and the peak area of the peaks obtained, types of hyperlipidemia could be recognized.

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Two kinds of immobilized enzyme layers, one containing NADH oxidase (layer I ) and the other, NADH oxidase and alcohol dehydrogenase (layer II), are prepared and are separately combined with Clark oxygen electrodes. The resulting enzyme electrodes are used for the determination of NADH. The detection limits are 2 μmol.dm^-3 for the electrode with the layer I and 20 nmol.dm^-3 for that with the layer II in the presence of ethanol. The amplification of electrode response obtained through the cyclic enzymatic reactions between NADH and NAD⁺ brings about the high sensitivity in the latter system.

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Synthetic bilayer membranes are constructed from a variety of synthetic amphiphiles, which include double-chain amphiphiles similar to biolipids, triple-chain amphiphiles, single-chain amphiphiles that contain rigid segments, and other related compounds. Bilayer formation can be confirmed by electron microscopic observation, differential scanning calorimetry, molecular weight measurement, etc. of aqueous dispersions. Synthetic bilayer membranes display physicochemical characteristics essentially identical with those of biolipid bilayers, and are advantageous for constructing molecular recognition systems. For instance, specific surface structures of some synthetic bilayers induce specific binding of dye molecules. Interaction of molecules and ions with surface receptors can cause changes in orientation and distribution of component molecules, which can be detected readily by spectroscopic and other means.

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Double-chain alkyl derivatives with poly(_L-glutamic acid)- and poly(_L-aspartic acid)-head groups were synthesized and their aggregate morphologies in dilute aqueous solutions were investigated. These polyamino acid derivatives were dispersed in water at above pH4 to form a variety of helical superstructures composed of single-walled bilayer membranes, whose morphologies were closely related to the chemical structures of hydrophilic head groups. The helical structures were not observed in the corresponding ammonium amphiphiles without polyamino acid-head groups and the amphiphile with low-molecular head groups or with poly(_DL-amino acid) head groups. The developmental mechanism to helical superstructures was concluded by following the metamorphosis of bilayer aggregates from poly(_L-aspartic acid) derivatives in aqueous solutions: the helical forms are induced via the formation of double or multiple helix among the untwisted filaments produced by incubating.

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The crystal structure of an azobenzene-linked, single-chain ammonium amphiphile (C₆-AzoC₅N⁺Br^-), C₂₇H₄₂N₃O₃Br, was determined by X-ray diffraction. The crystal is triclinic with the space group P1, Z=2, a=2.7446(9), b=0.8592(1), c=0.6112(1)nm, α=106.91(2), β=87.05(2), and γ=93.18(4)°. The structure was solved by the direct method and r efined by the block-diagonal least-squares method to the R-value of O.060 for 3535 reflections (sinθ/λ<0.56). In contrast to other azobenzene derivatives, azobenzene part of the C₆-AzoC₅N⁺Br^- molecule has very good planarity. tortion angles between the azo moiety and the benzene rings are within 2°. The zigzag planes of the spacer alkyl and the tail alkyl parts are linked to the azobenzene plane with small tortion angles, O.1 and 6.3°, respectively. this shapes the whole molecule a long thin plate. The crystal structure consists of regularly stacking bimolecular layers along the α-direction in which azobenzene chromophores aggregate in the J-like (head-to-tail) fashion between adjacent molecules. The detailed, molecular and crystal structure of C₆AzoC₅N⁺Br^- is very similar to that of the previously analyzed homologous compound, C₁₂AzoC₅N⁺Br^-.

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Self assemblies of 10-(1-pyrenyl)decanoic acid (PDA) have been studied by fluorescence spectroscopy. In a pH 5.0 buffer solution, PDA showed both monomer and aggregate fluorescence emissions (Fig.1). A fluorescence excitation band due to the PDA aggregate was observed at 354 nm even when the spectrum was recorded at a monomer emission wavelength, indicating the occurrence of energy transfer from the aggregate(s) to the monomer. At higher pH, PDA was dissolved in water giving the monomer emission (Fig.1), and formed micelles at concentrations above 2×10^-5mol.dm^-3 (Figs.5 and 6). Fluorescence excitation spectra (Fig.5) as well as the fluorescence decay curves (Fig.7)suggest the occurrence of energy transfer from the aggregate(s) to the monomer and from the monomer to the nonfluorescent energy trap(s) in the PDA micelles. Below the cmc, PDA molecules also aggregated spontaneously upon addition of NaCl resulting in fluorescence quenching of PDA by NaCl (Fig.2). The fluorescence decay curves were composed of fast and slow components (Fig.4). This result as well as those of thefluorescence spectral measurements indicates that energies transferred from the PDA monomer to the nonfluorescent PDA aggregates. An excimer-like fluorescence of PDA was observed for a Langmuir-Blodgett membrane composed of PDA and stearic acid (1:12 molar ratio)at around 470 nm (Fig.8). Both monomer and excimer-like emissions decayed multiexponentially (Fig.9), indicating the occurrence of energy transfer from the monomer and excimer-like states to the nonfluorescent energy trap(s). An intermolecular π-π interaction between the pyrenyl moieties of PDA seems to be too weak to organize the PDA molecules regularly in water and the position of the pyrenyl moiety in the PDA molecule is not adequate for forming well-organized LB membranes,

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lipid membranes which have different mobilities were investigated. Furthermore, mechanism of L-cell attachment was also investigated in detail. Two types of oriented lipid membranes were prepared on an alkylated glass surface. One was liquid crystalline state consisted of dimyristoylphosphatidylcholine (DMPC), the other was gel state consisted of dipalmitoylphosphatidylcholine (DPPC) at 37°C. L-cells attached remarkably to DPPC oriented membrane which was gel state at 37°C. And L-cell attachment to DPPC oriented membrane depended on the presence of Ca²⁺ in the medium (Fig.8). L-cells, which had attached to DPPC or DMPC oriented membrane, were detached almost completely by trypsin treatment (Table 2). That indicated membrane protein of L-cell might play important role in cell attachment. The degree of L-cell attachment to DPPC oriented membrane was decreased by cytochalasin B or colchicine pretreatment which inhibits functions of cytoskeleton (Fig.9). However, the ratio of proliferation showed almost the same value on both membranes (Fig.10). According to these results, it was suggested that L-cell recognized membrane mobilities actively and attached to oriented lipid membrane in gel state.

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