1. Department of Chemistry
Using Macromolecule Release to Characterize Thermoresponsive Hydrogels Containing Metal Nanostructures
Nolan T. Flynn
Department of Chemistry
Wellesley College
We have investigated the release of macromolecules from poly(N-isopropylacrylamide)-based hydrogels containing metal nanostructures synthesized in situ. Finding from our studies include:
molecular weight of macromolecule alters the release behavior as shown below, left
similar release for native and gold nanostructure containing hydrogels below the hydrogel’s phase transition temperature
cessation of release at higher temperature for native hydrogels whereas hydrogels containing gold nanostructures and a disulfide bridged cross-linking agent exhibit continued release up to 40 °C as illustrated below, left
charge strongly influences macromolecular release from poly(N-isopropylacrylamide)-based hydrogels—specifically, results show increased loading but slower release with anionic macromolecules from cationic hydrogel matrices and the opposite trend is observed for anionic macromolecules and anionic hydrogel matrices
release behavior follows a Fickian diffusional models for low molecular weight species as shown below, right
Macromolecular release from 0.00M/3.50C hydrogels containing gold nanostructures.
Diffusional exponents for release from all native hydrogels at 25 °C.