Advanced Glycation End products (AGEs) are a group of amino-acid modifications produced with sugars or di-carbonyls. Some AGEs are known to affect health through binding to the receptor of AGEs (RAGE). Here, we propose a method for screening RAGE-binding AGEs by a competitive assay using purified RAGE and AGEs-specific antibody. This method has clarified that at least carboxyethyl lysine and pentosidine among methylglyoxal-derived AGEs are involved in RAGE binding, suggesting that this would be a promising method for classifying RAGE-binding AGEs.

This paper introduces some studies on the development of separation technologies for environmental remediation that have been performed in my laboratory over the past 20 years. The studies are related mainly to the development of easily collectable adsorbents and eco-friendly remediation technologies to remove pollutants from contaminated environments. First, the investigation of pollution in the Songhua River in China is described because it was that research that gave me the opportunity to consider the necessity of an easily collectable adsorbent. Then, the separation methods using the modified magnetite to remove pollutants by a magnet are introduced and the development of adsorbents that can float up to the water surface after adsorption at the bottom of the water is described. Electrochemical methods to accumulate pollutants in water on a carbon fiber electrode and electro-kinetic remediation to remove pollutants in soil are also introduced.

Two solutions that are individually fed at the same flow rate into two separate microchannels of a microchip, combine to form a single channel (a Y-type microchannel). This flow is either parallel for immiscible solutions or initially parallel, but then becomes homogeneous through diffusion, for miscible solutions. However, a new type of microfluidic behavior in a Y-type microchannel that was neither parallel nor homogeneous flow has been observed using, for example, water/acetonitrile (3:4.5, v/v) and acetonitrile/ethyl acetate (3.5:4, v/v) mixed solutions. Each mixed solution was marked with distinctive dyes and delivered at the same flow rate into a Y-type microchannel under laminar flow conditions. In the single channel, the two phases were initially observed to flow in parallel, but then apparently swapped to flow on the opposite wall while retaining parallel flow with a slight change in the components of the two phases. We have named this type of laminar flow “microfluidic inverted flow” for ternary water/hydrophilic/hydrophobic organic solvent mixed solutions. The inverted flow of a ternary water/acetonitrile/ethyl acetate system was examined in detail under various flow conditions. We also proposed a concept of response microfluidic analysis based on such microfluidic inverted flow.

Procalcitonin (PCT) and C-reactive protein (CRP) are significant complementary inflammatory markers, and their simultaneous detection is of substantial value. In this article, a rapid, simple and cost-effective method for the dual quantitative detection of PCT and CRP in serum is discussed. Two UCNPs of similar size and morphology, but with a different emission spectrum, were prepared for the simultaneous detection of PCT and CRP by lateral flow assay (LFA) technology in a direct method. With the developed dual test strips and signal read system, the assay results present a limit of detection (LOD) of 0.12 ng/mL and 0.24 μg/mL for PCT and CRP, respectively. In addition, both of the coefficients of variation and positive and negative concordance rates for PCT or CRP are well compared with those of the traditional method. The dual detection of PCT and CRP have shown great application potential in medical diagnosis and treatment guidance.

Basal cell carcinoma (BCC) in paraffin-embedded specimens was investigated by nondestructively electron paramagnetic resonance (EPR) and X-band (9.45 GHz) EPR imaging (EPRI). A histopathological examination of specimens showed the melanin contents and revealed that they were predominantly of the nodular types. A single-line EPR pattern was observed in the BCC specimens, and the spectra of the samples were analyzed using linewidth and spectral pattern parameters. The eumelanin-related radical was observed in paraffin-embedded BCC specimens. The stability of the radical was supported by sepia pigment experiments. The g-value and peak-to-peak linewidths (ΔH_pp) were 2.004₆ and 0.61 ± 0.02 mT (mean ± SEM), respectively. Strong EPRI signals correspond to areas of strong pigmentation in the samples. Thus, histopathological examination, EPR, and EPRI of BCC specimens showed that the radical distribution reflects on the spatial distribution of pigments in the samples.

Silver nanoprisms (AgNPrs) have a unique localized surface plasmon resonance, resulting in strong absorption and scattering within the visible light region. In this work, we propose image acquisition from colloidal solutions of AgNPrs using a combination of transmitted and scattered light. The developed measurement technique could be carried out by separately recording transmitted and scattering images of the solutions, using a mobile device camera prior to a calculation of the empirical absorption value (I_A). The I_A value of green for AgNPrs solutions was found to be in agreement with the absorption spectra obtained using a conventional spectroscopic technique. This technique was utilized for the quantifications of hydrogen peroxide and glucose. Good linearities between ΔI_A and those typical analytes were observed. The limit of detection for the typical biosensor of glucose was 19.8 μM. As such, we expect the methodology herein developed for hydrogen peroxide and glucose determinations by means of monitoring the color change of transmitted and scatting images from solutions to contribute to the development of simple, rapid, and reliable detection systems to be further applied to biochemical analysis and clinical diagnosis, as well as to household biosensor applications.

We rationally designed an ultrasensitive and label-free sensing platform for determination of cadmium (Cd). The sensing platform contains G-quadruplex-Cd(II) specific aptamer (GCDSA) constructed by incorporating G-rich sequence at the end of 5′ and the critical domain of the Cd-4 aptamer. GCDSA designed act as both a special recognition sequence for Cd²⁺ and a signal DNAzyme. In absence of Cd²⁺, GCDSA may mainly exist in a random coil sequence. Upon addition of Cd²⁺, GCDSA could probably be induced to fold into a G-quadruplex structure. The generation of plentiful active G-quadruplex interacts with hemin to form a peroxidase-like DNAzyme, leading to increased absorbance signal of the sensing system. ΔA was directly proportional to the two segments of concentrations for Cd²⁺, with the detection of limit of 0.15 nM. The proposed method avoids the labeled oligonucleotides and allows directly quantitative analysis of the samples by cheap instruments, with an excellent dynamic range.

The traditional pretreatment methods for the determination of cadmium in grain are time-consuming, cost-consuming, and unfriendly to human health and the environment. To eliminate these disadvantages, we developed an accurate, time-, energy- and cost-efficient method for determination of Cd in grain coupled with graphite furnace atomic absorption spectrometry (GFAAS). The optimization conditions of the extraction were achieved, the accuracy was verified and a collaborative study was organized to evaluate the methods. The detection limit and quantification limit were 0.016 and 0.048 μg L⁻¹, respectively. The whole pretreatment time was reduced to 15 min, and there was no significant difference (P >0.05) between the extraction method and the classic pretreatment method. The method proved to be highly consistent with the results of laboratories in different countries, as determined from two international proficiency tests (| Z | ≤0.3). The repeatability, reproducibility, and HorRat values of the collaborative results were 2.7 – 4.9%, 9.4 – 11.7%, and 0.42 – 0.58, respectively. The method of diluted acid mild extraction coupled with GFAAS is efficient, cost-saving, convenient and friendly.

We report on the structures of Li-ion complexes in salt-concentrated aqueous electrolytes based on lithium bis(trifluoromethanesulfonyl)amide (LiTFSA), particularly focusing on the anion coordination behavior of the ion-pair complexes in the high concentration region c_Li > 3.0 mol dm⁻³. Quantitative data analysis of the Raman spectra revealed the following. (1) Li ions do not coordinate with TFSA anions at lower c_Li (<3.0 mol dm⁻³) to exist as ion pair-free ions. (2) In the concentrated region (c_Li = 3.0 – 4.0 mol dm⁻³), the TFSA anions coordinate as monodentate ligands (mono-TFSA) with Li ions to form ion-pair complexes and coexist with free TFSA in the bulk. (3) Further increasing the c_Li (4.0 – 5.2 mol dm⁻³) results in both monodentate and bidentate coordination (bi-TFSA) modes of TFSA anions to Li ions, yielding complicated ion-pair complexes in the first coordination sphere. The Walden plots, based on ionic conductivity and viscosity data, implied that the ion-conducting mechanism in the highly salt-concentrated region was considerably different from that in the dilute region (i.e., vehicle mechanism).

An analytical method for concurrent analysis of inorganic anions and cations has been developed using a capillary electrophoresis (CE)–capacitively coupled contactless conductivity detector (C⁴D) system. Although hydrodynamic and electrokinetic injection techniques have been widely used in CE, we employed a capillary filling method (CFM) for the analysis of inorganic ions. The procedure is relatively simple and has the advantage that CMF does not require pressure control and vial exchange. Three anions (chloride, sulfate, nitrate) and five cations (ammonium, potassium, sodium, magnesium, calcium) were successfully separated and detected at ppm levels within 80 s using a 9 mM histidine/15 mM malic acid (pH 3.6) containing 50 mM N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate as background electrolyte. Applying this analytical condition, the electroosmotic flow is negligible and anions and cations were migrated concurrently to different polarities according to their electrophoretic mobility. Obtained raw data showed stepwise increases in detected conductivity due to the migration of sample components, which expresses as peak profiles by differentiation of electropherograms. The RSD values of the peak area and migration times for the anions and cations were satisfactory and were less than 5.15 and 2.04%, respectively. The developed method was applied for the analysis of inorganic anions and cations in commercial mineral waters, tap water, urine, and exhaled breath condensate. These results indicate that the CE-C⁴D system with CFM is suitable for the rapid analysis of inorganic anions and cations in various samples.

Cypridina luciferase is a bioluminescent enzyme that has been used as a reporter either in gene expression reporter assays or in immunoassays accompanied by an antibody. To develop a novel bioluminescent assay for the detection of 5-hydroxymethylcytosine, we first conjugated Cypridina luciferase to the antibody against 5-hydroxymethylcytosine. Next, we performed modifications of guanine bases in the genome DNA samples with 4-azidophenylglyoxal and the biotinylation via the azide-Staudinger ligation, which allowed streptavidin to capture and immobilize the genome DNA samples under mild conditions. The detection of 5-hydroxymethylcytosine in the genome DNA samples was performed with the conjugates between Cypridina luciferase and the reduced antibody, which was also confirmed by a surface plasmon resonance assay with the antibody alone. The results obtained from the bioluminescent assay were in good agreement with that of the surface plasmon resonance assay. We succeeded in the detection of 5hmC in the genome DNA samples from the dinoflagellate Pyrocystis Lunula by using this method.

Water-soluble nonionic polymers of polyethylene glycol (PEG), poly(vinyl alcohol) (PVA), and polyvinylpyrrolidone (PVP) were examined to develop the dispersion of graphene in an aqueous surfactant solution. Sodium dodecylbenzenesulfonate was used as an anionic surfactant to disperse graphene in an aqueous solution and to give negative charge on it. The dispersion of graphene was monitored through the electropherograms in affinity capillary electrophoresis; a broad peak for the dispersed graphene and shot signals for the aggregated one. When PEG was added in the separation buffer as an affinity reagent, the number of the shot signals in the electropherogram was reduced; PEG can develop the dispersion of graphene in an aqueous surfactant solution. The dispersion was also developed with PVP or PVA. The effective electrophoretic mobility of the dispersed graphene was reduced by using the polymer as an affinity reagent. The result suggested that the anionic surfactant on the graphene surface was competitively substituted with the nonionic polymer. The degree of the decrease in the effective electrophoretic mobility was larger with PEG with a high-molecular mass. The broad peak of the dispersed graphene got narrower by the addition of PEG, and the number of theoretical plates was improved.

To quickly and accurately quantify the redox dynamics of c-type cytochromes (c-Cyts) in a living cell suspension, diffuse-transmission UV/visible (DT-UV/Vis) and normal UV/Vis spectroscopy were used to record spectra of c-Cyts in living Shewanella oneidensis MR-1 bacteria. DT-UV/Vis showed a higher absorbance of c-Cyts and lower background compared with normal UV/Vis, because interference from cell surface scattering was removed. The extinction coefficients of oxidized c-Cyts (410 nm) and reduced c-Cyts (419 and 552 nm) were observed. Using this method and the obtained c-Cyts extinction coefficients, the redox transformation kinetics of c-Cyts under anoxic conditions were successfully examined in the presence of various electron acceptors, including 9,10-anthraquinone-2,6-disulfonic acid, Cr(VI), Fe(III) citrate and oxygen. Therefore, the in situ spectral analysis of outer-membrane proteins of intact cells using DT-UV/Vis spectroscopy appears a promising method for investigating microbial metal reduction processes in living cell systems.

A simplified method using a single column of N,N,N′,N′-tetraoctyl diglycolamide (TODGA) resin is developed for the separation of Sr, Nd and Hf with matrix and interference elements from geological samples, and for subsequent determination of their isotopic ratios by multi-collector inductively coupled plasma–mass spectrometry (MC-ICP-MS). The analytes of Sr, Nd and Hf are absorbed by the TODGA resin and eluted with 6 mol/L HNO₃, 1.2 mol/L HCl and 1 mol/L HNO₃–1.6 mol/L HF, respectively. The separation procedure is validated by the certified reference materials (CRMs) of BHVO-2, BCR-2 and AGV-2 with analyte recovery greater than 97%. The ratios are measured for ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd and ¹⁷⁶Hf/¹⁷⁷Hf and the mean values (2σ) are 0.703455 (16), 0.512977 (12) and 0.283108 (8) for BHVO-2, 0.705008 (18), 0.512633 (10) and 0.282878 (4) for BCR-2, and 0.703989 (20), 0.512791 (8) and 0.282982 (8) for AGV-2, which are consistent with the certified values.

The heme-based O₂ sensor from Escherichia coli, EcDOS, exerts phosphodiesterase activity towards cyclic-di-GMP (c-di-GMP), an important second messenger that regulates biofilm formation, virulence, and other important functions necessary for bacterial survival. EcDOS is a two-domain protein composed of an N-terminal heme-bound O₂-sensing domain and a C-terminal functional domain. O₂ binding to the heme Fe(II) complex in the O₂-sensing domain substantially enhances the catalytic activity of the functional domain, a property with potentially promising medical applications. Mesoporous silica is a useful material with finite-state machine-like features suitable for mediating numerous enzymatic functions. Here, we successfully encapsulated EcDOS into mesoporous silica, and demonstrated that encapsulated EcDOS was substantially activated by CO, an alternative signaling molecule used in place of O₂, exhibiting the same activity as the native enzyme in aqueous solution. Encapsulated EcDOS was sufficiently stable to exert its enzymatic function over several experimental cycles under aerobic conditions at room temperature. Thus, the present study demonstrates the successful encapsulation of the heme-based O₂ sensor EcDOS into mesoporous silica and shows that the native gas-stimulated function of EcDOS is well conserved. As such, this represents the first application of mesoporous silica to an oxygen-sensing—or any gas-sensing—enzyme.

Meat screening plays a significant role in human health and religion. But the identification methods for beef were little reported. In this work, a simple colorimetric method based on denaturation bubble-mediated strand exchange amplification (SEA) was developed for the rapid and sensitive identification of beef. The whole strategy was performed on a portable metal bath and the distinguishable color between positive and negative controls was observed directly by the naked eyes. The feasibility using crude extraction samples by a heating treatment in PBS for 2 min was evaluated in duck spiked by beef. The result demonstrated that the developed method could identify as low as 1% (w/w) beef/duck within 50 min. Meanwhile, the results showed the method had a good repeatability and specificity. Therefore, this assay allows for the rapid, sensitive, specific detection of beef, and can be recommended as an effective, promising strategy for on-site meat identification.

A supported liquid membrane (SLM) system for the selective separation of platinum(IV) from palladium(II) has been developed. The SLM was prepared using imidazolium-based IL 1-octy-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. The initial flux and separation factor of Pt(IV) from Pd(II) were found to significantly depend on the composition of the receiving solution. Based on the performance, a 0.1 mol dm⁻³ NaClO₄ solution was selected as a suitable receiving solution. Membrane transport experiments showed that 93% of Pt(IV) can be selectively transported into the receiving solution, whereas most Pd(II) remains in the feed solution.

We propose the creation of reusable indicator-sorbed-solids, using anion-exchange resins or kaolin as supports, with the aim to reduce chemical use towards green analytical chemistry. Indicators (phenolphthalein, thymol blue and butterfly pea flower extract as a natural indicator) sorbed on a solid support, were employed in acid-base titration, in both homogenous aqueous and heterogenous aqueous organic phases. Applications of the developed techniques to some real samples, such as vinegar, colored fruit juice and vegetable oil, have been demonstrated.