High Sensitive Visual Protein Detection by Microfluidic Lateral Flow Assay with On-Stripe Multiple Concentration

Lateral flow assays (LAFs) especially integrated with a microfluidic chip, provides a simple, rapid, user-friendly, potable robust, and cost-effective technology for broad assays. However, this technology suffers from low sensitivity. In this paper, one kind of automatic roller of tap, which can be precisely controlled to replace sample tap was integrated into the microfluidic LAFs platform. And then, on-stripe repeated injection and concentration were realized with this simple mechanic unit. The minimum detection concentration for human chorionic gonadotropin (HCG) was 1.26 ng/mL, comparable with literature using complex enzyme/chemical reaction-based signal amplification. The linear relationship between the signal intensity and enrichment times reflected the good reproducibility of the novel device. At the same time, the good linear relationship between the predicted accumulation quantity of HCG and the gray value of bands is very meaningful for quantitative detection. Consequently, this novel universal approach shows great potential in the rapid trace analysis and broaden the application of LAFs with its attractive characteristics.