Preparation of multilayer films consisting of glucose oxidase and poly(amidoamine) dendrimer and their stability

Supramolecular dendrimer-containing layer-by-layer nanoassemblies for bioapplications: current status and future prospects

This review provides a comprehensive and critical overview of the supramolecular dendrimer-containing multifunctional layer-by-layer nanoassemblies driven by a multitude of intermolecular interactions for biological and biomedical applications.

Recent developments in smart antibacterial surfaces to inhibit biofilm formation and bacterial infections

Since their development over 70 years, antibiotics are still the most effective strategy to treat bacterial biofilms and infections.

Glucose Oxidase-Based Glucose-Sensitive Drug Delivery for Diabetes Treatment

The glucose-sensitive drug delivery systems based on glucose oxidase (GOD), which exhibit highly promising applications in diabetes therapy, have attracted much more interest in recent years. The self-regulated drug delivery systems regulate drug release by glucose concentration automatically and continuously to control the blood glucose level (BGL) in normoglycemic state. This review covers the recent advances at the developments of GOD-based glucose-sensitive drug delivery systems and their in vivo applications for diabetes treatment. The applications of GOD-immobilized platforms, such as self-assembly layer-by-layer (LbL) films and polymer vesicles, cross-linking hydrogels and microgels, hybrid mesoporous silica nanoparticles, and microdevices fabricated with insulin reservoirs have been surveyed. The glucose-sensitive drug delivery systems based on GOD are expected to be a typical candidate for smart platforms for potential applications in diabetes therapy.

Phenylboronic Acid-Functionalized Layer-by-Layer Assemblies for Biomedical Applications

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. The responses of PBA-modified LbL assemblies arise from the competitive binding of sugars to PBA in the films or oxidative decomposition of PBA by H₂O₂. Electrochemical glucose sensors have been fabricated by coating the surfaces of electrodes by PBA-modified LbL films, while colorimetric and fluorescence sensors can be prepared by modifying LbL films with boronic acid-modified dyes. In addition, PBA-modified LbL films and microcapsules have successfully been used in the construction of drug delivery systems (DDS). Among them, much effort has been devoted to the glucose-triggered insulin delivery systems, which are constructed by encapsulating insulin in PBA-modified LbL films and microcapsules. Insulin is released from the PBA-modified LbL assemblies upon the addition of glucose resulting from changes in the permeability of the films or decomposition of the film entity. Research into insulin DDS is currently focused on the development of high-performance devices that release insulin in response to diabetic levels of glucose (>10 mM) but remain stable at normal levels (~5 mM) under physiological conditions.

Preparation of Layer-by-Layer Films Composed of Polysaccharides and Poly(Amidoamine) Dendrimer Bearing Phenylboronic Acid and Their pH- and Sugar-Dependent Stability

Layer-by-layer films composed of polysaccharides and poly(amidoamine) dendrimer bearing phenylboronic acid (PBA-PAMAM) were prepared to study the deposition behavior of the films and their stability in buffer solutions and in sugar solutions. Alginic acid (AGA) and carboxymethylcellulose (CMC) were employed as counter-polymers in constructing LbL films. AGA/PBA-PAMAM films were successfully prepared at pH 6.0-9.0, whereas the preparation of CMC/PBA-PAMAM film was unsuccessful at pH 8.0 and 9.0. The results show that the LbL films formed mainly through electrostatic affinity between PBA-PAMAM and polysaccharides, while, for AGA/PBA-PAMAM films, the participation of boronate ester bonds in the films was suggested. AGA/PBA-PAMAM films were stable in the solutions of pH 6.0-9.0. In contrast, CMC/PBA-PAMAM films decomposed at pH 7.5-9.0. The AGA/PBA-PAMAM films decomposed in response to 5-30 mM fructose at pH 7.5, while the films were stable in glucose solutions. Thus, AGA is useful as a counter-polymer for constructing PBA-PAMAM films that are stable at physiological pH and decompose in response to fructose.

Recent progress in electrochemical biosensors based on phenylboronic acid and derivatives

This review provides an overview of recent progress made in the development of electrochemical biosensors based on phenylboronic acid (PBA) and its derivatives. PBAs are known to selectively bind 1,2- and 1,3-diols to form negatively charged boronate esters in neutral aqueous media and have been used to construct electrochemical glucose sensors because of this selective binding. PBA-modified metal and carbon electrodes have been widely studied as voltammetric and potentiometric glucose sensors. In some cases, ferroceneboronic acid or ferrocene-modified phenylboronic acids are used as sugar-selective redox compounds. Another option for sensors using PBA-modified electrodes is potentiometric detection, in which the changes in surface potential of the electrodes are detected as an output signal. An ion-sensitive field effect transistor (FET) has been used as a signal transducer in potentiometric sensors. Glycoproteins, such as glycated hemoglobin (HbA1c), avidin, and serum albumin can also be detected by PBA-modified electrodes because they contain hydrocarbon chains on the surface. HbA1c sensors are promising alternatives to enzyme-based glucose sensors for monitoring blood glucose levels over the preceding 2-3months. In addition, PBA-modified electrodes can be used to detect a variety of compounds including hydroxy acids and fluoride (F(-)) ions. PBA-based F(-) ion sensors may be useful if reagentless sensors can be developed.