[Frontiers in Bioscience E2, 657-667, January 1, 2010]

A comparative study on two phenylboronic acid based glucose-sensitive hydrogels

Fenghua Xu1, 2, Guiyang Liu1, 2, Qiang Zhang1, Ronald A. Siegel3

1School of Pharmaceutical Sciences, Peking University, Beijing 100083, China, 2Department of Pharmaceutics, PLA General Hospital, Beijing 100853, China, 3Department of Pharmaceutics, University of Minnesota, Minneapolis, MN 55455, US

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and Methods
3.1. Reagents and instruments
3.2. Synthesis of acrylaminophenylboronic acid (A•PBA)
3.3. Synthesis of poly(ethylene glycol) diacrylate (PEG•A2)
3.4. Preparation of hydrogel A•PBA-DMAPMA-EGDMA and hydrogel A•PBA-PEG
3.5. The pH- and glucose/fructose-sensitivity of the hydrogel
3.6. Morphology study of the hydrogels
3.7. Response rate of the hydrogel to the change of glucose concentration
4. Results
4.1. The pH- and glucose/fructose-sensitivity of hydrogel A•PBA-DMAPMA-EGDMA
4.2. The pH- and glucose/fructose-sensitivity of hydrogel A•PBA-PEG
4.3. The stability of the hydrogel to buffers
4.4. Morphology study of the hydrogels
4.5. Responses to the variation of glucose concentration
5. Discussion
6. Conclusions
7. Acknowledgement
8. References

1. ABSTRACT

Two phenylboronic acid based glucose-sensitive hydrogels, A•PBA-DMAPMA-EGDMA and A•PBA-PEG, were initially prepared by free-radical polymerization. Swelling properties of the gels were studied by determining the diameter changes in different buffer solutions, with or without glucose or fructose. The hydrogels were designed as "valves" to control the flow of glucose solutions. The results showed that gel A•PBA-DMAPMA-EGDMA was sensitive to pH and glucose, but not to fructose. It shrunk in weak basic solution and the addition of glucose made it shrink more. In this gel PBA moiety and glucose is supposed to form a 1:2 bis-bidentate complex. Hydrogel A•PBA-PEG was sensitive to pH, glucose and fructose, all of which made it swell in weak basic solution. A 1:1 complex is believed to form between PBA and glucose/fructose in this gel. All the stimuli-responses are reversible and the glucose-responses occurred in the range of the physiological/pathological glucose level. Both A•PBA-DMAPMA-EGDMA and A•PBA-PEG exhibited sufficient volume change to the alteration of glucose concentration and could be employed as a "valve" to control liquid flow in weak basic solution.