Miniaturized real-time monitoring system for l-lactate and glucose using microfabricated multi-enzyme sensors

Abstract

A miniaturized on-line monitoring system for the detection of l-lactate and glucose is presented. The system is based on a microfabricated multi-enzyme silicon sensor chip with flow channels integrated on the chip. The sensors were fabricated in containment technology. They were characterized in test solutions. The cross-talking behaviour was investigated and was found to be practically negligible. The linear measurement ranges of both glucose and lactate sensors were large enough for most practical applications. As a result of the miniaturization the analyte consumption could be reduced to a few nmol min −1. The system was equipped with a microdialysis probe whose recovery was 45% for lactate and 37% for glucose in test solutions using a flow rate of 3 μl min −1. Lower flow rates of 0.5 μl min −1 resulted in recoveries of over 90%. The long-term stability of the system was acceptable. Initial measurements have also been performed in vitro using human blood serum.