Abstract
Integrating cell lysis and DNA purification process into a micrototal analytical system (μTAS) is one critical step for the analysis of nucleic acids. On‐chip cell lysis based on a chemical method is realized by sufficient blend of blood sample and the lyzing reagent. In this paper two mixing models, T‐type mixing model and sandwich‐type mixing model, are proposed and simulation of those models is conducted. Result of simulation shows that the sandwich‐type mixing model with coiled channel performs best and this model is further used to construct the microfluidic biochip for on‐line cell lysis and DNA extraction. The result of simulation is further verified by experiments. It asserts that more than 80% mixing of blood sample and lyzing reagent which guarantees that completed cell lysis can be achieved near the inlet location when the cell/buffer velocity ratio is less than 1:5. After cell lysis, DNA extraction by means of a solid‐phase method is implemented by using porous silicon matrix which is integrated in the biochip. During continuous flow process in the microchip, rapid cell lysis and PCR‐amplifiable genomic DNA purification can be achieved within 20 min. The potential of this microfluidic biochip is illustrated by pretreating a whole blood sample, which shows the possibility of integration of sample preparation, PCR, and separation on a single device to work as portable point‐of‐care medical diagnostic system.