Introduction & Objective: Glucose limiting membranes (GLM) are essential components of continuous glucose monitors (CGM), often generated as blends of hydrophobic and hydrophilic polymers. Blending may complicate processing steps for manufacturers with issues including a need for multiple solvents and strict control of casting conditions to avoid inhomogeneities and macrophase separation. DSM Biomedical has developed new amphiphilic thermoplastic polyurethanes (TPUs) called the Sparsa platform to serve as single component GLMs that achieve required properties without blending.
Methods: Sparsa TPUs were synthesized via a two-step, prepolymer and chain extension method. The formulation was varied to evaluate impact of polymer hardness and hydrophilicity. Permeability of glucose and oxygen through the membranes were analyzed utilizing a Franz cell experiment and oxygen transmission rate instrument respectively. Microphase architecture was evaluated using AFM and SAXS. Fouling behavior was investigated using a quartz crystal microbalance technique and bovine serum albumin. Biocompatibility was evaluated using the L929 MEM elution test and histology following implantation in a porcine model.
Results: Sparsa TPUs were tunable to desired glucose permeability levels and cast from a single solvent. Microstructure and performance were minimally sensitive to fluctuation in ambient humidity during casting. Protein fouling was substantially reduced compared to conventional TPUs. Sparsa TPUs did not cause cytotoxicity and tissue response was similar or less pronounced than for a commercial CGM sensor.
Conclusion: Sparsa TPUs demonstrate tunability in glucose permeability and simplify production of CGMs. Technical properties and biocompatibility indicate Sparsa TPUs can replace current GLMs with improved or equivalent performance.
A. Martinez: None.
