Transduction of pH and glucose-sensitive hydrogel swelling through fluorescence resonance energy transfer

Hydrogel structures have been studied, and the promise of smart materials for myriad uses is driving research and development of pH- and temperature-sensitive polymers for many applications. However, the typical method of measuring and quantifying hydrogel swelling is still inaccurate. To improve this situation, alternative transduction schemes for the measurement of swelling in pH- and glucose-sensitive hydrogels are being pursued. In this paper, transduction of hydrogel swelling through fluorescence resonance energy transfer (FRET) is described for two pH-sensitive systems: chitosan/gelatin and poly(acrylamide-co-acrylic acid) (poly(AM-co-AA)). Comparison between weight change and spectral shifts from hydrogels immobilized on optical fibers confirms the feasibility of the approach. Furthermore, nanocomposite materials for optimizing the sensitivity are being investigated.