Glucose-Sensitive Hydrogel Optical Fibers Functionalized with Phenylboronic Acid

Hydrogel optical fibers having a poly(acrylamide-co-poly(ethylene glycol) diacrylate) p(AMco-PEGDA) core and a Ca alginate cladding was created. 3-(acrylamido)phenylboronic acid (3-APBA) molecules were covalently incorporated into the core for sensing glucose. The changes of the physical and optical properties of the hydrogel fiber sensors in response to glucose were investigated. Quantitative readouts were obtained from measuring the changes in the intensity of transmitted light through the hydrogel optical fibers. The light attenuation and RIs of p(PEGDA), p(AM-co-PEGDA), and Ca alginate were measured. Light was not attenuated at wavelengths longer than 400 nm. Increase in the concentration of the Na alginate from 1 to 4 wt% enhanced light attenuation. As the concentration of acrylamide increased, the RI decreased from 1.50 to 1.46. PEGDA was co-polymerized with AM to obtain flexible hydrogels. The RIs of p(PEGDA) hydrogels showed la linear relationship with increasing monomer concentration. At the minimum monomer concentration, the RI of p(PEGDA) hydrogel was higher than the RI of Ca alginate hydrogel with maximum concentration The RIs of the hydrated p(AM-co-PEGDA), p(PEGDA) hydrogel and Ca alginate were significantly lower than their nonhydrated states. Based on the optical properties of the core and cladding materials, p(AM-co-PEGDA), p(PEGDA), and Ca alginate precursors were optimized to construct the hydrogel optical fibers.