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Predecessor
Volume 61, Issue 12
Displaying 1-10 of 10 articles from this issue
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Shinji HIGASHIYAMA, Katsuhiro ISODA, Masaya KAWASE, Kiyohito YAGI2004 Volume 61 Issue 12 Pages 587-594
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPolyamidoamine dendrimers are known to be highly branched cascade Polymers. By immobilizing fructose-modified dendrimers on a polystyrene culture plate (fructose-dendrimer), one could maintain the number of initially adhered hepatocytes and the urea synthesis activity. We found that hepatocytes formed spheroids when cultured on fructose-dendrimer. However, the adhesion was not sufficiently strong and the spheroids detached easily to the culture medium. Because galactose is a ligand for the asialoglycoprotein receptor on the hepatocyte cytoplasmic membrane, it was chosen as another ligand for modification in order to maintain adhesion of spheroids for long periods. Simultaneous modification of dendrimers with fructose and galactose had a marked effect on spheroid adhesion. The suppression of apoptosis and necrosis was observed in hepatocyte spheroids cultured on a dendrimer modified with fructose and galactose (F/G dendrimer). Moreover, the hepatocyte spheroids cultured on the F/G dendrimer had higher activities of liver-specific functions, such as urea synthesis and albumin gene expression, than those cultured on single-ligand-modified dendrimers. Thus, immobilization of mixed-ligand-modified dendrimers could generate a suitable surface for hepatocyte spheroid formation. These dendrimers could be a powerful tool for generating custom-made scaffolds for cells other than hepatocytes if one selects suitable ligands for each cell type. This surface-modification technology will contribute to the development of tissue engineering.View full abstractDownload PDF (5631K) -
Atsushi IKAI2004 Volume 61 Issue 12 Pages 595-600
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSI have studied the nano-mechanics of protein-based bio-structures to understand their fundamental properties that support the success of the life processes on this planet. I found that the intra-molecular structure of the globular protein is mechanically heterogeneous, with brittle local structures showing resistance against the tensile force of destruction. I also measured the force required to extract intrinsic membrane proteins from the live cell membrane and compared the measured force with that required for pore formation to the membrane. As the result, I propose a new method of harvesting membrane proteins from live cell membranes without destroying the organism.View full abstractDownload PDF (1563K) -
Shinichi MOCHIZUKI, Arihiro KANO, Toshihiro AKAIKE, Atsushi MARUYAMA2004 Volume 61 Issue 12 Pages 601-605
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSCarbohydrates have several unique biofunctions that are useful for drug delivery systems. If one plans to utilize these functions, glycoconjugate design and chemistry are important. Glyco-conjugate materials consisting of polymeric materials and polysaccharide for DDS were described. Liver sinusoidal endothelial cells (LSECs) possess unique receptors that recognize and internalize hyaluronan (HA). We used this characteristic of HA and the unique assembling properties of comb-type polycations with DNA to develop a system for targeting foreign DNAs for LSECs. New comb-type copolymers composed of HA and PLL (PLL-g-HA) formed complexes with DNA, permitting specific targeting of DNAs to the LSECs. The PLL-g-HA gene carrier system may open a new and more effective strategy to treat intractable liver diseases through manipulation of LSECs functions by gene engineering.View full abstractDownload PDF (5479K) -
Tadanori YAMADA, Masaharu SENO, Akihiko KONDO, Masakazu UEDA, Katsuyuk ...2004 Volume 61 Issue 12 Pages 606-612
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSHepatitis B virus envelope L proteins produced in yeast cells form hollow nanoparticles (L particles, average diameter 220nm) displaying human liver-specific receptor. Recently, the L particles were found to incorporate genes, proteins, and drugs, and act as an efficient pinpoint delivery system to human liver-derived tissues in xenograft models. By substituting the epidermal growth factor (EGF) for human liver-specific receptor, the mutated L particles showed the affinity to the EGF receptor, not to human liver. Other similar HBV envelope proteins, e. g., M and S particles, have already been commercialized for hepatitis B vaccine, strongly suggesting the safety of L particles in human. These results indicate that the hollow bio-nanoparticles are a promising candidate for the next-generation platform of DDS, especially that related to gene therapy.View full abstractDownload PDF (3826K) -
Kenichi HATANAKA, Naoto KATAOKA, Maria Carmelita Z. KASUYA, Kohsaku OK ...2004 Volume 61 Issue 12 Pages 613-616
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSDi-O-carboxymethylation of β-cyclodextrin was investigated. The use of chloroacetic acid and sodium hydroxide in water was found not to give di-O-carboxymethylated product. Di-O-carboxymethylated β-cyclodextrin was obtained by using potassium hydroxide as a base. When bromoacetic acid was used instead of chloroacetic acid, di-O-carboxymethylated β-cyclodextrin was obtained in a shorter period of time. The reaction of β-cyclodextrin with methyl chloroacetate and sodium hydride in dimethylformamide solution and subsequent hydrolysis of the methyl esters also gave di-O-carboxymethylated β-cyclodextrin. Condensation reaction of di-O-carboxymethylated β-cyclodextrin with hexamethylenediamine gave a polyamide of a molecular weight of 104.View full abstractDownload PDF (911K) -
Yoshiharu HATAKEYAMA, Masahiro MINAMI, Mitsuo UMETSU, Satoshi OHARA, S ...2004 Volume 61 Issue 12 Pages 617-622
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSHighly selective base-pairing rules in DNA can be utilized as a tool for assembling nano particles. Holliday Junctions, where two different DNA double strands intersect and replace the complement strand, are an important artificial motif for forming two-dimensional“plane”conformations of DNA. In this study, we controlled the growth of the DNA“plane”conformations by changing the temperature. A set of DNA single chains were cooled from 90°C to 4°C for 10 minutes, to form the DNA“plane”conformation. The influence of the cooling procedure on the DNA conformation was observed by atomic force microscope (AFM). The DNA“plane”conformation is strongly dependent on the cooling process. Further, we assembled gold nano particle using the DNA conformation; then we observed the assembly of gold nano particle on the DNA conformation by transmission electron microscopy (TEM).View full abstractDownload PDF (10059K) -
The Adsorption of Lysozyme on Mesoporous Carbon Molecular SievesMasahiko MIYAHARA, Ajayan VINU, Takashi NAKANISHI, Katsuhiko ARIGA2004 Volume 61 Issue 12 Pages 623-627
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe adsorption of lysozyme on mesoporous carbon, i. e., CMK-3 and CMK-1, from buffered solutions of different pH (pH=6.5-12) has been studied. The amount adsorbed depends on the solution pH as well as on the pore size. The maximum adsorption was observed near the isoelectric point of lysozyme, suggesting that suppression of electric repulsion between the enzymes is an important factor in the adsorption process. The unaltered structural characteristics of the mesoporous adsorbents after the adsorption have been confirmed by physico-chemical characterization techniques such as XRD and N2 adsorption. In addition, IR spectroscopic studies confirmed that the proteins used in this study are stable even after adsorption on the mesoporous carbon.View full abstractDownload PDF (1108K) -
Akinori TSURUMA, Masaru TANAKA, Nobuyuki FUKUSHIMA, Masatsugu SHIMOMUR ...2004 Volume 61 Issue 12 Pages 628-633
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSRecently, micro-nano fabrication has become an important way to modify material's surfaces for reguration of adhesion and growth of cells in tissue engineering. In neuroscience, micro-patterns on culture substrates are critical for neurological implants and are also significant to investigate neuron-patterned surface interactions. In previous studies, the patterns have been fabricated by lithography and microcontact printing techniques. However, these techniques need high energy and many processes and restricted can only treat a list of materials for substrates. In this study, we prepared self-organized honeycomb-patterned films by a casting technique. We cultured neurons on the patterned films for neural tissue engineering and investigated the morphology of neural cell bodies and neural network by a confocal scanning microscope and a scanning electron microscope. We found that neurons formed neural network along the honeycomb patterns and that the morphologies of attached cells depended on pore size of the patterned films. These results suggest that honeycomb-patterned films provide guidance of neurite extension and influence the morphologies of neurons.View full abstractDownload PDF (7913K) -
Takehisa DEWA, Yukari IEDA, Kazuyuki MORITA, Kiyotaka YOSHIDA, Li WANG ...2004 Volume 61 Issue 12 Pages 634-639
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThree types of polycationic phospholipids conjugates were synthesized to develop a novel nonviral gene carrier. The conjugates composed of a polyamine portion: spermidine, spermine or polyethylenimine (PEI), and a phospholipid portion: dipalmitoylphosphatidic acid (DPPA) were synthesized via a synthetic intermediate, ethylbrominated DPPA. The polycationic lipids exhibited moderate transfection efficacy evaluated by β-galactosidase assay. These conjugates form a micelle-like assembly in aqueous solution, whose sizes are in the range of 90-220 nm. The formation of the conjugate-DNA complex was observed by using atomic force microscopy (AFM). The AFM images revealed that the conjugate-bearing spermidine, which showed the most efficient transfection, enables one to form a compact complex (-130 nm in width) with DNA, while the conjugate-bearing PEI, which showed a less efficient transfection, forms a large complex (-200 nm) with DNA.View full abstractDownload PDF (3026K) -
Hidenobu SHIMIZU, Tomomi YOKOHARA, Risei WADA, Masaru OKABE, Li WANG2004 Volume 61 Issue 12 Pages 640-642
Published: December 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThermosensitive block copolymers of poly (N-isopropylacrylamide) (PNIPAM) and poly (ethylene glycol) (PEG) were synthesized by the redox reaction of the hydroxyl end group of PEG with a ceric ion. The effects of polymerization temperature and NIPAM concentration on the molecular weight of block copolymers were investigated. The molecular weight of the copolymer was found to increase in an exponential manner with an increase in NIPAM concentration when the polymerization was performed below the lower critical solution temperature (LCST) of PNIPAM. At a temperature above the LCST, on the other hand, few NIPAM monomers were polymerized regardless of NIPAM concentration, and the molecular weight of the block copolymers obtained was almost the same as that of the original PEG. These results indicate that above the LCST polymeric micelles are formed during polymerization and the polymerization hardly proceeds within the hydrophobic core of the polymeric micelles.View full abstractDownload PDF (598K)
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