Development of a needle-type biosensor for intravascular glucose monitoring

A needle type glucose biosensor has been developed for monitoring glucose levels during the hemorrhagic shock in trauma patients. The sensor employs polyurethane, cellulose acetate or PVC layers as an outer glucose diffusion and protective membrane, and glucose oxidase enzyme entrapped in poly(1,3-phenylenediamine) film. Sensor performance was evaluated in vitro and the sensor shows a sensitivity of up to 35 nAmM and a linear range of up to 38 mM. Evaluation of the sensor response in serum showed similar sensitivity and linear range as obtained using calibration curves in buffer solution. The sensor has a short response time of 23 s. The sensors were operated continuously for 14 days in phosphate buffer solution, and no significant change in the sensitivity and the linear range was observed during the first 5 days. Sensors show a minimum change in their performance when stored inactive in buffer at 4 °C for at least eight weeks.