Synthesis and characterization of sol-gel phase-reversible hydrogels sensitive to glucose
Abstract
Hydrogels have been used in various applications ranging from controlled drug delivery to biotechnology. Many hydrogels have the ability to respond (i.e., either swell or shrink) to the changes in environmental stimuli, such as pH and temperature. Such a response has been limited to changes in the size of hydrogels in the same gel phase. Currently, there are no hydrogels which undergo sol-gel phase transformation in the presence of a specific molecule such as glucose. A novel sol-gel phase-reversible hydrogel which undergoes phase transformation by changes in glucose concentration in the surrounding solution was synthesized. To make hydrogels phase-reversible, a physical bonding, rather than chemical bonding, was used to form crosslinks. The specific interaction between glucose and Concanavalin A (Con A) was utilized to induce the glucose-sensitive sol-gel phase transition. Glucose containing copolymers were synthesized using allyl glucose and vinylpyrrolidinone. Mixing of the solutions of copolymer and Con A resulted in the formation of gel. The efficiency of gel formation increased as the copolymer concentration decreased and/or the Con A concentration increased. Upon addition of free glucose, the gel became a sol as a result of replacement of the polymer-attached glucose by free glucose. The removal of the free glucose from the sol by dialysis caused the gel formation again. The sensitivity of the hydrogel to glucose can be adjusted by controlling the concentrations of copolymer and Con A. This glucose-sensitive phase-reversible hydrogels can be used to design self-regulating insulin delivery devices based on hydrogels.
Degree
Ph.D.
Advisors
Park, Purdue University.
Subject Area
Pharmaceuticals|Pharmacology|Polymers
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