The objective of the present study is to develop and investigate the swelling behavior of pH-sensitive Superporous Hydrogel (SPH) and SPH composite (SPHC). A novel superporous hydrogel containing poly (methacrylic acid-co-acrylamide) was synthesized from methacrylic acid and acrylamide through the aqueous solution polymerization, using N,N-methylenebisacrylamide as a crosslinker and ammonium pe...

pH-responsive hydrogels are capable of converting chemical energy to mechanical work. To optimize their use as actuators, their response when operating against an external load must be fully characterized. Here, the actuation strain of a model pH-sensitive hydrogel as a function of different constant loads is studied. The experimental actuation strain, produced by switching the pH from 2 to 12,...

This paper describes a whole cell sensor using E. coli entrapped within photocrosslinked hydrogel beads. Hydrogel beads containing organophosphorus hydrolase (OPH)-expressed E. coli were prepared by adding a hydrogel precursor solution containing the E. coli to an oil phase using a precision syringe pump, forming droplets, and photopolymerizing them. The beads showed good monodispersity with an...

Chitosan is a natural polymer which has limited solubility. Chitosan gets solubilized at acidic pH but is insoluble at basic pH. In the present study, carboxymethyl chitosan (CMC) was prepared which shows high swelling in basic pH and thus can delay the drug release and can act as matrix for extended release formulation. CMC was characterized by FTIR and NMR. pH-sensitive hydrogels of theophyll...

We describe and characterize elementary designs for electrochemical micro- and macro-scale chemomechanical hydrogel actuators. The actuation of a pH-sensitive cross-linked polyacrylic acid (PAA) hydrogel is driven in the model devices through the oxygen reduction reaction (ORR) occurring at the electrodes of an embedded Au mesh micro-electrochemical array. Proton consumption by the ORR at the c...

In the present work, a novel interpenetrating polymer network (IPN) hydrogel composed of crosslinked chitosan and poly(acryl acid) was prepared by crosslinking using glutaraldehyde. The model drug, cis-platin, was loaded into the resulted IPN hydrogel. Water absorption of the hydrogel could be switched on and off swiftly by control of pH of the surrounding environment. Therefore, the synthesize...

Environmentally sensitive hydrogels have enormous potential in various applications. Some environmental variables, such as low pH and elevated temperatures, are found in the body. For this reason, either pH-sensitive and/or temperature-sensitive hydrogels can be used for site-specific controlled drug delivery. Hydrogels that are responsive to specific molecules, such as glucose or antigens, can...