Miniaturized thermal biosensors

A summary of our efforts to develop miniaturized biosensors based on the enzyme thermistor is presented. Three constructions are described. The work focuses on the measurement of glucose in whole blood.

The first biosensor was used to analyze concentrated and tenfold diluted blood samples. The glucose concentration obtained using this construction correlated well with the reference method.

Using the second biosensor, the response time could be reduced from 3 minutes down to 30 seconds using a sample volume of 1 μl. The relative standard deviation for 100 blood samples (3.8 tnM) was 3.7%.

Micromachining technology was used to construct the third thermal biosensor on a silicon chip. Enzymes were immobilized directly onto the 30 parallel flow channels. Injection of 200 samples containing 10 mM hydrogen peroxide gave a relative standard deviation of 3%.