Sensors for monitoring the level of glucose in the human body for the treatment of Diabetes Mellitus are very dependent on the selectivity of permeation through a membrane enveloping the electro-chemical sensor.  For sensors dependent on an immobilized glucose oxidase enzyme, the membrane surrounding the sensor requires a specific ratio of oxygen and glucose permeation to be effective.  Very often the membrane is formulated as a physical blend of a hydrophilic polymer enabling glucose transportation and a hydrophobic polymer enabling oxygen transport.  Achieving the correct morphology for selective permeation can pose a challenge when employing a physical blend of dissimilar polymers.  In this study, a single, amphiphilic thermoplastic polyurethane (TPU) was formulated having a soft segment composed of a hydrophobic, polydimethylsiloxane (PDMS) and a hydrophilic, polyethylene glycol (PEG). Different synthetic variations were tried with the objective being to determine how these variations affected the permeation properties of the TPU. The variations included the mass ratio of PDMS to PEG in the soft segment and the hard segment weight percentage (%HS). The impact of TPU composition on transport properties was determined. TPUs having a greater PDMS to PEG mass ratio showed enhanced oxygen transport properties but diminished water uptake and glucose transport properties. Increasing %HS also reduced water uptake and glucose transport properties but did not appear to impact oxygen transport over the investigated range. Taking advantage of the observed trends, it is possible to tailor materials to target specific oxygen and glucose transport properties. Feasibility is demonstrated by monitoring the performance of a glucose sensor coated by these materials.

Permeation properties of polyurethanes for sensory medical devices

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.