Chemorheology of phenylboronate-salicylhydroxamate crosslinked hydrogel networks with a sulfonated polymer backbone.

Hydrogel networks crosslinked with polymer-bound phenylboronic acid (PBA) and salicylhydroxamic acid (SHA) demonstrate pH-reversible gel behavior due to the pH-dependent equilibrium of the crosslinking moieties that form the gel network. Furthermore, the pH at which gels behave dynamically can be controlled by use of a polyelectrolyte backbone. Here we report on the frequency-dependent chemorheological characterization of PBA-SHA crosslinked hydrogel networks with a sulfonated polymer backbone.

Temperature and pH sensitive hydrogels: an approach towards smart semen-triggered vaginal microbicidal vehicles.

Microbicides are drug delivery systems (DDSs) for the prevention of sexual transmission of HIV and other STDs. A topically applied vaginal microbicidal gel should provide uniform coating of vaginal tissue, retention of this gel layer prior to intercourse, and controlled release kinetics of antivirals to inactivate the viral load potentially introduced during sexual activity. Here, we describe the microbicide-oriented characterization of a DDS made with a dual pH sensitive and thermosensitive smart polymer gel composed of a random terpolymer of N-isopropyl acrylamide, butyl methacrylate, and acrylic acid.

Disulfide cross-linked hyaluronan hydrogels.

A new disulfide cross-linking strategy was developed to prepare hyaluronic acid (HA) hydrogel from thiol-modified HA. First, dithiobis(propanoic dihydrazide) (DTP) and dithiobis(butyric dihydrazide) (DTB) were synthesized and then coupled to HA with carbodiimide chemistry. Next, disulfide bonds of the initially formed gel were reduced using dithiothreitol (DTT) to give, after exhaustive dialysis, the corresponding thiol-modified macromolecular derivatives HA-DTPH and HA-DTBH.