Multi-channel Microfluidic Chip And Its Rapid Positioning And Detection

The CD (compack disk)-like microfluidic system is a kind of simple andpractical microfabricated platform. It would be a valuable tool in biochemistryanalysis applied in point-of-care diagnostic and pharmaceutical synthesis, etc. In thispaper, we made an analysis of the architecture of microfluidic chip and thefluid flow in micro-channel and designed an experimental detection platformof microfluidic chip.The step valve of microfluidic chip is used to stop the liquid flow, bythe contact angle hysteresis. In micro-channel which buttons by PDMS and glass,Whether the capillary flow occurrs that depends on the aspect ratio of thechannel. In order to analyze the dynamic effect in the process of stopping thecapillary by the step valve in microchannel, the relationship between the dynamiceffect of the capillary and the length before the step valve was researched。For theseries of microchannel with the depth of40μm and width from200μm to400μm,the calculated length before the step valve is from4.5316μm to10.081μm，whenthe step valve can stop the capillary effectively. The experiment for water cut-offin micro-channl was made according to the simulation data,and the auctul lengthbefore the step valve is from10μm to2000μm. The result shows that the stepvalve can stop the capillary effectively. I designed and made the mode ofmicrofludic chip based on the need of experiment for chip. The driving force ofmicrofluidic chip system is centrifugal force and capillary force. The capillary forcefor capillary gets form the proper aspect ratio of micro-channel. The centrifugal force required for the chip system is though the DSP control of brushless DCmotor.The speed of brushless DC motor is form2000rpm to4000rpm withthe speed accuracy of±1rpm. Centrifugal force is to achieve mixing of reagents andseparation of chip. Microfluidic chip reaches the specified location by the motorcontrol. The accuracy of motor positioning is±0.27°. Finally, we use theoptical system to detect the chip.In this paper, we made an analysis on the feasibility of the detection system ofthe multi-channel microfluidic chip.The rapid positioning and detectionexperimental platform was designed according to the demand of the chip.The experimental platform can reach high detection accuracy.