Microfabricated microdialysis microneedles for continuous medical monitoring

Enzyme based biosensors suffer from loss of activity and sensitivity through a variety of processes. One major reason for the loss is through large molecular weight proteins settling onto the sensor and affecting sensor signal stability and disrupting enzyme function. One way to minimize loss of sensor activity is to filter out large molecular weight compounds before sensing small biochemicals such as glucose. A novel microdialysis microneedle is introduced that is capable of excluding large MW compounds based on size. Preliminary experimental evidence of membrane permeability is shown, as well as diffusion and permeability modeling. Solutions should be able to equilibrate across the microdialysis membrane in a few seconds, as opposed to a few minutes with existing technologies. Microdialysis microneedles present an attractive first step towards decreasing size, patient discomfort and energy consumption of portable medical monitors over existing technologies.