Glucose biosensor with a hydrophilic polyurethane (HPU) blended with polyvinyl alcohol/vinyl butyral copolymer (PVAB) outer membrane

A high-performance glucose sensor capable of continuous monitoring has been developed. The sensor is based on an enzyme immobilization technique using electropolymerization of a non-conducting poly(p-aminophenol) (pAP) film on a plasma-deposited platinum electrode, followed by the introduction of a hydrophilic polyurethane (HPU) membrane mixed with polyvinyl alcohol/vinyl butyral copolymer (PVAB) as an outer membrane. Use of non-conducting polymer films for immobilization of glucose oxidase (GOx) results in the creation of a uniform film surface well suited for high enzyme loading. The biocompatible HPU membrane blended with optimized amount of amphiphilic PVAB membrane on the enzyme layer displays excellent characteristics that result in extended linear range, prevent sensor fouling and effectively eliminate interferences from sample solutions. The physical properties of mixed outer membranes, such as O2 and glucose permeability, were also tested. The optimized glucose sensor capable of continuous monitoring was found to have good sensitivity, a wide response range and fast response time (<5 s). The lifetime of the sensor in a buffer solution was over 20 days, while the lifetime in human serum was about 3 days.