A membrane that limits biofouling is critical to extend the lifetime and efficacy of implanted glucose biosensors. When cycled above and below its volume phase transition temperature (VPTT, ~33 °C), poly(N-isopropylacrylamide) (PNIPAAm) hydrogels undergo deswelling and reswelling, respectively. This process effectively removes adhered proteins and cultured cells in vitro. We propose that a PNIPAAm-based hydrogel membrane could control biofouling in vivo via a “self-cleaning” mechanism induced by transdermal thermal cycling. This approach is feasible if the membrane can be designed with rapid deswelling/swelling kinetics for efficient cell release, adequate mechanical properties and also sufficient glucose diffusion. In this work, several parameters were explored to achieve these properties including, incorporation of polysiloxane nanoparticles, a double network hydrogel matrix design and incorporation of an electrostatic comonomer. The impact of these design variables on key membrane properties were assessed, including: deswelling/reswelling behavior (gravimetric and differential scanning calorimetry - DSC), morphology (SEM) and modulus & strength (compression tests). Thermally-driven in vitro cell release and in vivo studies with a rat model demonstrated encouraging results in terms of membrane self-cleaning behavior.

Self-cleaning membranes for implanted glucose biosensors

249th National Meeting (2015)

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