pH-Driven Enzymatic Breakdown and Release of Catalase from Alginate Hydrogel.

Stimuli-induced release resulting in biochemical transformations has received a lot of attention due to its application in controlled drug release. In this work, catalase (EC 1.11.

Chemical modification of α-chymotrypsin enabling its release from alginate hydrogel by electrochemically generated local pH change.

This study investigates the controlled release of α-chymotrypsin from an alginate hydrogel matrix. When protein molecules entrapped in the hydrogel matrix have a size smaller than the hydrogel pores, their hold/release from the polymer matrix are controlled by the electrostatic interaction between the guest molecules and host polymer. α-Chymotrypsin, as a model protein, was chemically modified with negatively charged species to change its pI and to convert its attractive interaction with a negatively charged alginate hydrogel matrix to a repulsion interaction allowing its release by pH-triggered signal.

Time-Separated Pulse Release-Activation of an Enzyme from Alginate-Polyethylenimine Hydrogels Using Electrochemically Generated Local pH Changes.

β-Glucosidase (EC 3.2.1.

Electrochemical and Biocatalytic Signal-Controlled Payload Release from a Metal-Organic Framework.

A metal-organic framework (MOF), ZIF-8, which is stable at neutral and slightly basic pH values in aqueous solutions and destabilized/dissolved under acidic conditions, is loaded with a pH-insensitive fluorescent dye, rhodamine-B isothiocyanate, as a model payload species. Then, the MOF species are immobilized at an electrode surface. The local (interfacial) pH value is rapidly decreased by means of an electrochemically stimulated ascorbate oxidation at +0.

Stimulation-Inhibition of Protein Release from Alginate Hydrogels Using Electrochemically Generated Local pH Changes.

The electrochemically controlled release of proteins was studied in a Ca-cross-linked alginate hydrogel deposited on an electrode surface. The electrochemical oxidation of ascorbate or reduction of O was achieved upon applying electrical potentials +0.6 or -0.

Multiple pH waves generated electrochemically and propagated from an electrode surface.

Local pH changes were produced upon electrochemical reactions. Cyclic application of reductive and oxidative potentials resulted in the formation of pH waves in the form of distinct solution layers. Multiple layers with basic and acidic pH values were visualized with a fluorescence confocal microscope following fluorescence of pH-dependent dyes.