Mechanistic analysis of protein delivery from porous poly(vinyl alcohol) systems

We report on the preparation of both porous and non-porous poly(vinyl alcohol) (PVA) hydrogels that can be used as carriers to release proteins. Non-porous gels were prepared by freezing and thawing of aqueous PVA solutions, while porous gels were formed by adding porosigens such as NaCl or ammonium carbamate into aqueous PVA solutions. Bovine serum albumin, a model protein, was loaded into non-porous prior to freezing and thawing, and release under various conditions was performed. The number of freezing/thawing cycles affected the initial rate of release, the amount of protein released, and the transport mechanism of BSA.