Novel hyaluronic acid coating for potential use in glucose sensor design

Biocompatibility issues such as protein deposition and fibrous capsule formation significantly reduce the sensitivity of implanted glucose sensors. One of the approaches to improve the sensor biocompatibility is to disguise the sensors with coatings that mimic body conditions. We anticipate that a biomimetic coating based on hyaluronic acid (HA) would minimize the problems related to protein deposition and fibrous tissue formation. Diffusion experiments were conducted to assess the transport properties of HA coating on a polyvinyl alcohol (PVA) membrane using a classic diffusion cell. HA was coated on PVA membranes, as cross-linked HA membranes alone have poor mechanical strength. The effective diffusivities of glucose and oxygen in a HA/PVA membrane (95% confidence interval) are 1 +/- 0.26 x 10(-4) and 1.42 +/- 0.34 x 10(-4) cm(2)/min, respectively. The effective diffusivities of glucose and oxygen in HA/PVA membranes were approximately two-thirds when compared with the diffusivities of glucose and oxygen (7.29 x 10(-5) and 2.34 x 10(-4) cm(2)/min, respectively) in pure PVA membranes. The results indicate that the HA/PVA membranes have transport properties similar to the commonly used pure PVA membranes, and thus may find usefulness as a coating for implantable glucose sensors.