A polymeric dual-channel amperometric biosensor chip capable of symmetrically splitting sample bands for parallel micro flow injection determination of glucose and lactate

Abstract

This paper presents a chip-based dual-channel micro flow injection biosensor system for parallel determination of two components that potentially interference with each other. With glucose and lactate being the model analytes, a hybrid polydimethylsiloxane (PDMS)–polycarbonate (PC) microfluidic chip with a Y-shaped main-to-branch channel network was designed. Glucose oxidase (GOD) and lactate oxidase (LOD) biosensors of amperometric type were separately prepared inside each of the two branch channels. A sample band injected into the main channel was split into two daughter bands at the bifurcated point of the Y-shaped channel. The daughter bands were delivered into branches where the two analytes in the daughter bands were independently detected by the GOD and LOD sensors, preventing the potential chemical crosstalk between the two sensors. Factors influencing the symmetry of splitting a sample band, in turn, the sensitivity and reproducibility of the system, were discussed. Symmetric splitting was realized by using back pressure regulators (BPR). Under optimized conditions, detection limits of 78 μmol L−1 for glucose and 127 μmol L−1 for lactate were observed with a sample volume of 20 nL and a sample throughput rate of 40 h−1. RSDs of 0.8–0.9% for peak heights were observed for 11 runs of a standard solution containing glucose and lactate both at 2 mmol L−1. The designed dual-channel biosensor chip was applied to the simultaneous determination of glucose and lactate in human serum samples.