A novel microfluidic chip for on-line monitoring of lactate

Based on optical absorption of color solution, a microfluidic chip with functions of mixing on chip and optical fibres detecting was developed to on-line monitoring the lactate during the cell and tissue culture. The channel width that decides the optical transmittance has been optimized to 250 μm through the optical design software (Zemax), and the full-mixing position and optical fibre detecting position of the channel in mi-crofludic chip used for mixing lactate and its reagent has been decided by simulation with computational fluid dynamics (CFD) software. Therefore, a microfluidic chip comprised by polydimethylsiloxane (PDMS) and slide, with the function of mixing on chip and on-line monitoring by optical fibres, has been achieved through microeletro-mechanical system (MEMS) processing. The experiments show that mixing of lactate and its reagent on chip and the on-line monitoring of lactate can be realized and the LOD of this chip is up to 0.52 mmol/L(47 mg/L), the response time is 130 s when the lactate concentration varies from 1 mmol/L to 5 mmol/L. This kind of microfluidic chip can meet the need for on-line monitoring of lactate.