Katsuhiko Sato

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Electrochemical enzyme sensors are suitable for simple monitoring methods, for example, as glucose sensors for diabetic patients; however, they have several disadvantages arising from the properties of the enzyme. Therefore, non-enzymatic electrochemical sensors using functional molecules are being developed. In this paper, we report the electroche...

In this study, glucose oxidase (GOx) was immobilized on the electrode surface by layer‐by‐layer and gel membrane technique and characterized the GOx immobilized film morphology, H 2 O 2 permeability, and glucose response. Concanavalin A (Con A)‐GOx multilayer electrodes showed higher glucose‐related current response than GOx‐bovine serum albumin ge...

Nanopore sensing measures the changes in charge and physical state around the nanopores as changes in ionic current. In this study, we performed vancomycin (VCM) sensing with nanopores modified via Au−S bonds with dithiobis(4‐butyrylamino‐ m ‐phenylboronic acid) (DTBA‐PBA), a derivative of phenylboronic acid (PBA) bearing a thiol. First, we modifie...

Nitroxyl radical compounds oxidize hydroxy groups and some amino groups upon application of an electric potential. The resulting anodic current depends on the concentration of these functional groups in solution. Thus, it is possible to quantify compounds containing these functional groups by electrochemical methods. Cyclic voltammetry has been use...

8-Azabicyclo[3.2.1]octan-8-ol (ABOOL) and 7-azabicyclo[2.2.1]heptan-7-ol (ABHOL) are the main homologues of hydroxylamine 2-azaadamantan-2-ol (AZADOL) and 9-azabicyclo[3.3.1]nonan-9-ol. Both homologues feature a small bicyclic backbone and are known to be stable; however, to date, they have not been used as catalysts for alcohol oxidation. Herein,...

Nitroxyl radicals are known to electrochemically oxidize thiols as well as alcohols and amines. In this study, a preliminary investigation of the electrochemical reaction of thiols with 9-azabicyclo[3.3.1]nonane N-oxyl (ABNO), 2-azaadamantane N-oxyl (AZADO), and nortropine N-oxyl (NNO), which are highly active due to their bicyclo structures, for u...

We previously reported that layer-by-layer (LbL) film prepared by a combination of 2,2,6,6-tetramethylpiperidinyl N-oxyl (TEMPO)-modified polyacrylic acid (PAA) and polyethyleneimine (PEI) were decomposed by application of an electric potential. However, there have been no reports yet for other polycationic species. In this study, LbL films were pr...

This paper describes the voltammetric behavior of a TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) modified electrode prepared by the electrochemical polymerization of nitroxyl radical precursor containing phenol side chain in aqueous solution. The prepared TEMPO-modified electrode exhibits a symmetrical reversible redox wave at +0.6 V versus Ag/AgCl...

Herein, it is reported that p-acetamidophenylboronic acid can be electrolytic cleavage of the carbon–boron bond to p-acetamidophenol at an electric potential of 1.2 V vs. Ag/AgCl in 100 mM phosphate buffer of pH 7.4 (containing 10% acetonirile). The electrochemical reaction was investigated by HPLC, LC with tandem mass spectrometry, and cyclic volt...

Nitroxyl radicals, such as 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO), can catalyze the electrochemical oxidation of alcohols and amines. Because the oxidation current obtained in this process depends on the concentration of alcohols and amines, this process can be applied to their sensing. However, the relatively high oxidation potentials requir...

Quantifying drug concentrations in vivo quickly and easily is possible using electrochemical methods. The present study describes the electrochemical detection of vancomycin (VCM) and other antibiotics from the current obtained using nitroxyl radicals as electrocatalysts. Nortropine N-oxyl (NNO), which is more active than 2,2,6,6-tetramethylpiperid...

Nanopore pH sensing is based on the interaction between the surface charge of the nanopore and ions passing through the nanopore. The nanopore surface charge can be derived from the acid‐base dissociation equilibrium of the modified polyelectrolyte. Various polyelectrolytes have been selected based on the acid dissociation constant of the monomer u...

A modified electrode was developed by immobilizing poly(azure A) (pAA) onto the surface of a glassy carbon electrode via the electropolymerization of azure A (AA). The pAA immobilized on the electrode exhibited redox response during cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The redox reaction obeyed the Nernst equation becau...

In this paper we propose a novel measurement for NO and ·OH by electrochemical detection using sesamol. Standard samples of the sesamol monomer and dimer were subjected to differential pulse voltammetry, resulting in their peaks being clearly separated and detected. Based on the oxidative dimerization of sesamol, the current simple, sensitive and s...

pH is one of the most important properties associated with an aqueous solution and various pH measurement techniques are available. In this study, Azure A-modified poly(methacrylic acid) (AA-PMA) was synthesized used to prepare a layer-by-layer deposited film with poly(allylamine hydrochloride) (PAH) on a glassy carbon electrode via electrostatic i...

Nitroxyl radical catalysts oxidize alcohols under an applied electric potential. It is possible to quantify the alcohol concentration from the resulting oxidation current. In this work, we evaluated the catalytic activity of nitroxyl radicals (or their corresponding hydroxylamines), including 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as represen...

Phenylboronic acid-bearing polyamidoamine dendrimer (PBA-PAMAM)/poly(vinyl alcohol) (PVA) multilayer films were prepared through the layer-by-layer (LbL) deposition of PBA-PAMAM solution and PVA solution. PBA-PAMAM/PVA films were constructed successfully through the formation of boronate ester bonds between the boronic acid moiety in PBA and 1,3-di...

The electrochemical reaction of H2O2 was promoted by an electrode modified with N ,N‐diethyl‐N‐(2‐methoxy‐ethyl)‐N‐methylammonium bis(trifluoromethylsulfonyl)imide (DEME‐TFSI) and hybrid polymer/silica particles, which consisted of an ionic liquid‐type polymer brush decorated with silica particles (PSiP). The electrode was prepared by dropping an a...

A carbon nanotube (CNT)‐modified electrode was fabricated by dropping a dispersion of multi‐walled CNTs in water‐soluble and amphiphilic phospholipid polymer with both dispersing ability and anti‐biofouling property onto a Au electrode. A poly(2‐methacryloyloxyethyl phosphorylcholine‐co‐n‐butyl methacrylate) (PMB) composed from 50 mol% of 2‐methacr...

Glucose-sensitive films were prepared by the layer-by-layer (LbL) deposition of poly(ethyleneimine) (H-PEI) solution and DNA solution (containing glucose oxidase (GOx)). H-PEI/DNA+GOx multilayer films were constructed using electrostatic interactions. The (H-PEI/DNA+GOx)5 film was then partially decomposed by hydrogen peroxide (H2O2). The mechanism...

The electrocatalytical activity of nortropine-N-oxyl (NNO) was evaluated by cyclic voltammetry in pH 7.4 phosphate buffer solution. The anodic peak current for choline was enhanced in a concentration-dependent fashion, showing that choline was oxidized by the electrocatalytic effect of NNO. A high linear response to the choline concentration rangin...

This work investigated a simple triglycerides (TGs) detection method combining an enzymatic reaction, using only lipase, and the electrocatalytic oxidation of glycerol with nortropine‐N‐oxyl (NNO). Tributyrin was employed as a model TG. In this method, TGs are degraded by lipase to glycerol and fatty acids, after which the glycerol reacts with NNO....

The nitroxyl radical of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) can electro-oxidize not only alcohols but also amines. However, TEMPO has low activity in a neutral aqueous solution due to the large steric hindrance around the nitroxyl radical, which is the active site. Therefore, nortropine N-oxyl (NNO) was synthesized to improve the catalytic...

H2O2-sensitive nanofilms composed of DNA and hemin-appended poly(ethyleneimine) (H-PEI) were prepared by a layer-by-layer deposition of DNA and H-PEI through an electrostatic interaction. The (H-PEI/DNA)5 film was decomposed by addition of 10 mM H2O2. H2O2-induced decomposition was also confirmed in the hemin-containing (PEI/DNA)5 in which hemin mo...

Hydrogen peroxide (H2O2)-sensitive layer-by-layer films were prepared based on combining phenyl boronic acid (PBA)-modified poly(allylamine) (PAH) with shikimic acid (SA)-modified-PAH through boronate ester bonds. These PBA-PAH/SA-PAH multilayer films could be prepared in aqueous solutions at pH 7.4 and 9.0 in the presence of NaCl. It is believed t...

Functional layer-by-layer (LbL) multilayer films using phenylboronic acid (PBA) have been typically prepared by exploiting the boronate ester bond between PBA and a diol polymer as the driving force. However, we have prepared PBA-containing LbL films through the electrostatic interaction of PBA and polycations, Poly(acrylamide-ran-3-acrylamidepheny...

Glutamate sensors were prepared using nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP)‐dependent glutamate dehydrogenase (GDH). Glutamate was determined from the anodic oxidation current of NADH and NADPH generated by the enzymatic reaction of GDH. These two types of GDH enzymes were deposited separatel...

Thin films were prepared using layer-by-layer (LbL) deposition of Nafion (NAF) and polycations such as poly(allylamine hydrochloride) (PAH), poly(ethyleneimine) (PEI), and poly(diallydimethylammonium chloride) (PDDA). Insulin was then adsorbed on the NAF-polycation LbL films by immersion in an insulin solution. The NAF-polycation LbL films were cha...

The electrocatalytic activity of a 2,2,6,6-tetramethylpipridine-N-oxyl (TEMPO)-modified electrode toward the oxidation of carbohydrates in phosphate buffer solution was investigated under neutral aqueous solution conditions at 25 °C. The modified electrode was prepared on the surface of a glassy carbon electrode by the electrochemical polymerizatio...

A phenylboronic acid (PBA)/polyvinyl alcohol (PVA) dispersion was prepared by mixing PBA and PVA solutions. The PVA/PBA conjugate precipitated due to binding of several PBAs to PVA and reduction of solubility. The formation of the PVA/PBA dispersion was affected by the ratio of PBA to PVA, the ionic strength, and the pH. The aim of this study was t...

Multilayer films that decompose in the presence of lactate were prepared by depositing phenylboronic acid-modified poly(allylamine) (PBA-PAH) and poly(vinyl alcohol) (PVA) on a lactate oxidase (LOx) layer. The layers adhered through boronate ester bonds. The resulting LOx(PBA-AH/PVA)10 film was stable in pH 7.4 solution but decomposed following the...

Recent progress in the development of phenylboronic acid (PBA)-functionalized layer-by-layer (LbL) assemblies and their biomedical applications was reviewed. Stimuli-sensitive LbL films and microcapsules that exhibit permeability changes or decompose in response to sugars and hydrogen peroxide (H2O2) have been developed using PBA-bearing polymers....

Poly (amidoamine) (PAMAM) dendrimer-release multilayer films were prepared using phenylboronic acid-modified PAMAM dendrimers (PBA-D) and poly (vinyl alcohol) (PVA) through boronate ester bonds. The (PBA-D/PVA)10 film was stable in pH 9.0 solution. Upon addition of H2O2, PAMAM dendrimers were released from the (PBA-D/PVA)10 film due to oxidative sc...

Multilayer thin films composed of phenylboronic acid (PBA)-modified poly(allylamine hydrochloride) (PAH), PBA-PAH, with different PBA contents were prepared to study the effect of PBA content on the stability of the films. An alternate deposition of PBA-PAH and poly(vinyl alcohol) (PVA) on the surface of a quartz slide afforded multilayer films thr...

Multilayer thin films prepared via layer-by-layer (LbL) deposition of phenylboronic acid-bearing poly(allylamine hydrochloride) (PBA-PAH) and poly(vinyl alcohol) (PVA) were combined with glucose oxidase (GOx) to develop LbL films that can be decomposed in response to glucose. LbL deposition of PBA-PAH and PVA on a GOx-modified quartz slide afforded...

Multilayer films comprising of glucose oxidase (GOx) and phenylboronic acid-modified poly(amidoamine) dendrimer (PBA-PAMAM) were prepared and their pH- and glucose-induced decomposition was studied. Multilayered GOx/PBA-PAMAM films were prepared through boronate ester linkages between PBA-PAMAM and carbohydrate chains of GOx. In contrast, preparati...

Insulin-containing microcapsules were prepared by a layer-by-layer (LbL) deposition of poly(allylamine hydrochloride) (PAH) and polyanions, such as poly(styrenesulfonate) (PSS), poly(vinyl sulfate) (PVS), and dextran sulfate (DS) on insulin-containing calcium carbonate (CaCO3) microparticles. The CaCO3 core was dissolved in diluted HCl solution to...

Nortropine-N-oxyl (NNO) was synthesized in a single step from nortropine. The electrocatalytical activity of NNO was evaluated by cyclic voltammetry in pH7.0 phosphate buffer solution. The anodic peak current for ethanol, isopropanol and glucose was enhanced, showing these alcohols were oxidized by electrocatalytic effect of NNO. On the other hand,...

Polymer-coated magnetic particles (MPs) were prepared to study the binding of fluorescence dye on the surface and its H2O2-induced release. For this goal, multilayer films were prepared by layer-by-layer deposition of shikimic acid-appended poly(allylamine hydrochloride) (SA-PAH) and poly(styrenesulfonate) (PSS) on the surface of MPs. 3-(Dansylamin...

Layer-by-layer (LbL) multilayer films were prepared using phenylboronic acid-modified poly(amidoamine) dendrimers and poly(vinyl alcohol) (PVA) in order to investigate the glucose sensitivity of the films. We used dendrimer derivatives modified with 3-carboxyphenylboronic acid (3CPBA-D) and 3-carboxy-5-nitrophenylboronic acid (3C5NPBA-D) to evaluat...

The release of insulin from insulin-containing CaCO3 microspheres was investigated. The microspheres were prepared by mixing aqueous solutions of CaCl2 and Na2CO3 in the presence of insulin. The surface of the insulin-containing CaCO3 microspheres was coated with a layer-by-layer thin film consisting of poly(allylamine hydrochloride) and poly(styre...

Layer-by-layer (LbL) films were prepared by an alternate deposition of phenylboronic acid-bearing poly(allylamine hydrochloride) (PBA-PAH) and poly(vinyl alcohol) (PVA) on the surface of a quartz slide to develop thin films that can be decomposed in response to hydrogen peroxide (H2O2). The PBA-PAH/PVA films decomposed in the presence of H2O2; the...

Poly(lactic acid) (PLA) microparticles were coated with layer-by-layer (LbL) films containing insulin and the pH-dependent release of insulin was studied. The LbL films were prepared on the surface of PLA microparticles by the alternate deposition of insulin and poly(allylamine hydrochloride) (PAH) through the electrostatic attraction between insul...

A graphite oxide-containing molecularly imprinted polymer (GO-MIP) was prepared by using pyridoxine as a template molecule. The adsorption behavior of pyridoxine to GO-MIP was studied based on Scatchard analysis. The fluorescence of pyridoxine was quenched on the GO-MIP. In contrast, GO-MIP did not exhibit quenching to the fluorescence of nontempla...

We present an overview of the recent progress in the development of layer-by-layer (LbL) assembled thin films and microcapsules for insulin delivery. The LbL deposition of insulin-containing thin films on the surfaces of flat substrates or microparticles has been investigated for orally administered insulin formulations. The amount of insulin in th...

We review the synthesis of dendrimer-containing layer-by-layer (LbL) assemblies and their applications, including biosensing, controlled drug release, and bio-imaging. Dendrimers can be built into LbL films and microcapsules by alternating deposition of dendrimers and counter polymers on the surface of flat substrates and colloidal microparticles t...

The present paper reports the use of an amphoteric copolymer, poly(diallylamine-co-maleic acid) (PDAMA), as a component of precursor layers (or sacrificial layers) for constructing free-standing layer-by-layer (LbL) films. A PDAMA-poly(styrenesulfonate) (PSS) film or PDAMA-poly(dimethyldiallylammonium chloride) (PDDA) film was coated on the surface...

Layer-by-layer (LbL) films were prepared over an aperture (diameter 1-5 mm) on a glass plate to study ion permeation across free-suspended LbL films. LbL films were prepared by depositing alternating layers of poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) on the surface of a glass plate with an aperture filled with an algin...

Layer-by-layer (LbL) thin films were prepared using an amphoteric copolymer consisting of alternating diallylamine and maleic acid monomer units (PDAMA), and pH-induced decomposition of the films was studied. LbL deposition of poly(styrene sulfonate) (PSS) and PDAMA on a solid surface afforded thin films at pH 3.0, while thin films did not form at...

Free-suspended polyelectrolyte multilayer (PEM) films were prepared over an aperture (diameter, 1 or 3 mm) in a glass plate to study ion permeation across the PEM films. PEM films were successfully constructed by layer-by-layer deposition of poly(allylamine hydrochloride) and poly(styrene sulfonate) on the surface of glass plate whose aperture had...

We present an overview of the preparation and properties of layer-by-layer (LbL) deposited thin films and microcapsules in relation to their use in the development of biosensors and controlled release systems. Enzyme biosensors can be constructed by immobilizing enzymes on the surface of electrodes by LbL deposition without loss of their catalytic...

Poly(methyl methacrylate) (PMMA) microcapsules were prepared by the in situ polymerization of methyl methacrylate (MMA) and N,N'-methylenebisacrylamide on the surface of calcium carbonate (CaCO(3)) particles, followed by the dissolution of the CaCO(3) core in ethylenediaminetetraacetic acid solution. The microcapsules were characterized using fluor...

Insulin-containing layer-by-layer (LbL) thin films were prepared by an alternate deposition of insulin and anionic polysaccharides (heparin, κ-carrageenan, and fucoidan) through an electrostatic force of attraction between positively charged insulin and anionic polysaccharides at pH 3.0. The loading of insulin in the LbL films increased with the in...

IntroductionAvidin-Containing LbL FilmsConcanavalin A-containing LbL FilmsDendrimer-Containing LbL FilmsInsulin-Containing LbL FilmsConclusions References

Layer-by-layer (LbL) thin films containing insulin were deposited on the surface of biodegradable poly(lactic acid) (PLA) microbeads and the pH-triggered release of insulin was studied. The LbL films were successfully prepared by the alternate deposition of insulin and poly(vinyl sulfate) (PVS) or dextran sulfate (DS) at pH 4.0 through the electros...

Layer-by-layer (LbL) thin films containing insulin were prepared by alternately depositing insulin and poly(allylamine hydrochloride) (PAH) onto a solid surface at pH 7.4. The deposition behavior of the LbL films was studied using a quartz crystal microbalance, UV-vis absorption spectrometer, ζ-potential analyzer, and an atomic force microscope. Th...

In this review, the preparation and properties of protein architectures constructed by layer-by-layer (LbL) deposition through avidin-biotin and concanavalin A (Con A)-sugar interactions are discussed in relation to their use for optical and electrochemical biosensors. LbL films can be constructed through the alternate deposition of avidin and biot...

Polyelectrolyte microcapsules with avidin-poly(styrene sulfonate) (PSS) membrane were prepared by a layer-by-layer deposition technique. The uptake and release of biotin-labeled fluorescein (b-FITC) as well as immobilization of biotin-labeled glucose oxidase (b-GOx) to the microcapsule were studied. The polyelectrolyte microcapsules were prepared b...

The present review provides an overview on the recent progress in the development of pH- and sugar-sensitive layer-by-layer (LbL) thin films and microcapsules in relation to their potential applications in drug delivery. pH-sensitive LbL films and microcapsules have been studied for the development of peptide and protein drug delivery systems to th...

Avidin-containing polyelectrolyte microcapsules were prepared by a layer-by-layer deposition technique and uptake and release of biotin-labelled fluorescein (b-FITC) was studied. The polyelectrolyte microcapsules were prepared by coating the surface of calcium carbonate (CaCO3) microparticles containing avidin-poly(styrene sulfonate) (PSS) conjugat...

The surface of an indium–tin oxide (ITO) electrode was coated with layer-by-layer (LbL) thin films composed of fluorescein-modified poly(allylamine) (F-PAH) and poly(styrenesulfonic acid) (PSS) and their UV–visible absorption spectra were recorded under the influence of electrode potential. The LbL films were prepared by an alternate deposition of...

Polyelectrolyte giant capsules whose diameter is in a millimeter level were prepared by a layer-by-layer deposition of poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) on an alginate (AGA)-Ca2+ sphere followed by dissolution of the AGA core in an ethylenediaminetetraacetic acid or NaCl solution. A fluorescent-labeled bovine se...

Copolymers consisting of N-3-acrylamidophenylboronic acid (APBA) and 2-hydroxyethyl methacrylate moieties (HEMA) were synthesized and their solubility and fluorescence properties were evaluated in the presence of sugar. The APBA–HEMA copolymer composed of 25mol% of APBA moiety was found to be poorly soluble in water at pH 7.4. However, the water so...

Sugar-sensitive microcapsules containing insulin were prepared by a layer-by-layer (LbL) deposition of alginic acid (AGA) and phenylboronic acid-modified poly (allylamine) (PBA-PAH) on the surface of a calcium carbonate (CaCO3) microparticle in which insulin had been embedded, followed by dissolution of the CaCO3 core. The microcapsules thus prepar...

Layer-by-layer (LbL) thin films composed of fluorescein-modified poly(allylamine) (F-PAH) and poly(styrenesulfonic acid) (PSS) were prepared on the surface of an indium-tin oxide (ITO) electrode and the electrode potential-dependent colorimetric response of the LbL films was studied in the presence of hydrogen peroxide (H(2)O(2)). The LbL films wer...

Layer-by-layer (LbL) deposited polyelectrolyte thin films containing insulin were prepared and the pH-triggered release of insulin was studied. Insulin-containing LbL films were successfully prepared by the alternate deposition of insulin and poly(vinyl sulfate) (PVS), poly(acrylic acid) (PAA), or dextran sulfate (DS) in acidic solutions (pH 1.0–3....

Poly(amidoamine) dendrimer-loaded microcapsules were prepared by a layer-by-layer deposition of poly(allylamine hydrochloride) and poly(vinyl sulfate) on the surface of calcium carbonate (CaCO3) microparticles that contain poly(amidoamine) dendrimer, followed by dissolution of CaCO3 core. A fluorescence spectroscopy revealed that a fluorescent dend...

The release of alpha,beta,gamma,delta-tetrakis(4-N-methylpyridyl)porphyrin (TMPyP) from layer-by-layer assembled thin films composed of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) was electrochemically controlled. The release rate of TMPyP was enhanced when a positive electrode potential (+1.2 to +1.5 V) was applied to the gla...

The sugar sensitive microcapsules were prepared by a layer-by-layer deposition of concanavalin A (Con A) and glycogen on a calcium carbonate particle containing fluorescein-labeled insulin (F-insulin). The Con A/glycogen multilayer capsules were formed through sugar-lectin interactions by using inner and outer poly(ethyleneimine)/poly(vinyl sulfate...

Layer-by-layer (LbL) thin films were prepared using carboxyl-terminated poly (amidoamine) dendrimers (generation, 3.5) (PAMAM-COOH) and poly (acrylic acid) (PAA). The stability of the LbL films in aqueous media was evaluated as a function of pH of the media. The PAMAM-COOH-PAA films were stable at pH 2.0-4.5, while the films were decomposed in the...

Dendrimer-containing multilayer thin films have successfully been prepared by a layer-by-layer deposition of carboxyl-terminated poly(amidoamine) dendrimer (PAMAM-COOH) and poly(methacrylic acid) (PMA) on a solid surface at pH 4.0, while the multilayer film did not form at pH 7.0. The PMA/PAMAM-COOH multilayer films prepared at pH 4.0 are decompose...

Layer-by-layer (LbL) deposited thin films composed of poly(methacrylic acid) (PMAA) and poly(amide amine) dendrimer (PAMAM) were prepared and pH-induced decomposition was studied using a quartz crystal microbalance (QCM). The PMAA/PAMAM LbL films can be successfully prepared in the acidic solutions through hydrogen bonding and electrostatic interac...

The effects of hydrogen peroxide on the electrochemical decomposition of layer-by-layer thin films composed of 2-iminobiotin-labeled poly(ethyleneimine) (ib-PEI) and avidin were studied. An ib-PEI/avidin thin film prepared on the surface of a platinum (Pt) film-coated quartz resonator was electrochemically decomposed in the presence of hydrogen per...

Protein thin films containing avidin and lectin have been prepared on solid surfaces to develop devices sensitive to pH and biomolccules. Concanavalin A (Con A), one of the glucose- and mannose-binding lectins, and glycogen were alternately deposited onto the surface of a quartz slide to prepare layer-by-layer (LbL) thin films, through strong Con A...

Polyelectrolyte multilayer microcapsules were prepared by a layer-by-layer deposition of poly(ethyleneimine) (PEI) or poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) on a calcium carbonate particle containing fluorescein isothiocyanate-concanavalin A (FITC-Con A)/glycogen conjugates. Fluorescence microscope and scanning elect...

A layer-by-layer assembly composed of avidin and 2-iminobiotin-labeled poly(ethyleneimine) (ib-PEI) was prepared on the surface of a platinum (Pt) film-coated quartz resonator, and an electrochemically induced disintegration of the avidin-ib-PEI assembly was studied using a quartz crystal microbalance. The resonance frequency of a five-bilayer (avi...

Multilayer thin films containing concanavalin A (Con A) and ferrocene-appended glycogen (FcGly) were prepared by a layer-by-layer deposition Con A and FcGly by biological affinity (lectin-sugar interaction) on a glassy-carbon electrode. The electrochemical response of the Con A-FcGly film-coated electrode to sugars was investigated. A cyclic voltam...

The fluorescence of fluoresceinisothiocyanate-labeled concanavalin A (FITC-Con A) was quenched by forming an FITC-Con A-glycogen conjugate and dequenched upon addition of sugars to the conjugate solution due to disaggregation of the conjugate. However, fluorescence quenching was barely observed upon formation of FITC-Con A-dextran conjugate. The su...

Layered thin films composed of concanavalin A (Con A) and sugar-bearing polymers were prepared by a layer-by-layer deposition of Con A and the polymer on a solid surface. The sugar-induced disintegration was studied. Con A-polymer layered films could be successfully prepared using a maltose-bearing polymer (PV-MA), while melibiose- and glucose-bear...

The glucose-sensitive multilayer films composed of concanavalin A (Con A)-dextran were studied for developing optical glucose sensors. The multilayer films were prepared on the surface of a quartz slide, which was treated in diclorodimethylsilane overnoght at room temperature. It was reported that the Con A-glycogen multilayer films were sensitive...

A layer-by-layer thin film composed of avidin and 2-iminobiotin-labeled poly(ethyleneimine) (ib-PEI) was prepared and their sensitivity to the environmental pH and biotin was studied. The avidin/ib-PEI multilayer assemblies were stable at pH 8-12, whereas the assemblies were decomposed at pH 5-6 due to the low affinity of the protonated iminobiotin...

Sugar-sensitive thin films were prepared by a layer-by-layer deposition of concanavalin A (Con A) and glycogen on the surface of a quartz slide and their sugar-induced decomposition was studied. The Con A/glycogen multilayer films can be decomposed by exposing them to sugar solutions (D-glucose, D-mannose, methyl-alpha-D-glucose and methyl-alpha-D-...

Layered assemblies containing cyclodextrin (CD) have been prepared by layer-by-layer deposition of poly(allylamine) and sulfonated a-CD or ß-CD on a solid surface. A quartz crystal microbalance study revealed that a-CD and ß-CD form multilayers in the films upon each deposition. The sulfonated-a-CD-containing film bound methyl orange (MO) by formin...

Sulfonated cyclodextrins (s-α-CyD and s-β-CyD) were employed for constructing photosensitive thin films containing azobenzene residues. Azobenzene-modified poly(allylamine hydrochloride) (Az-PAH) and s-α-CyD or s-β-CyD were deposited alternately on the surface of a quartz slide to prepare multilayer thin films. Az-PAH formed inclusion complex in th...

Polyelectrolyte-layered films containing α- and β-cyclodextrin were prepared by a layer-by-layer deposition of sulfonated α- or β-cyclodextrin (s-α-CyD or s-β-CyD) and cationic poly(allylamine hydrochloride) (PAH) on a solid surface. The deposition of the films from water solutions (no salt added) afforded thin films in which s-α-CyD and s-β-CyD fo...