Abstract: Objective To achieve the goal of the qualitative and relatively quantitative analysis of the target protein in a time-saving, labor-saving and reagents-saving way by the microfluidic paper-based immunoassay. Methods In this paper, we chose MGMT as the target protein and compared the qualitative and semi-quantitative results of the MGMT expression in the MCF7 cells which was treated with MGMT inhibitor, Lomeguatrib, in both the traditional Western Blotting and the paper chip immunoassay. Results Microfluidic paper-based immunoassay can make the qualitative and relative quantitative detection on protein expression. Compared to the sensitivity of 1-5ng of the traditional Western Blot, the microfluidic paper-based immunoassay could detect as low as 10-25 pg of the protein. The sensitivity could be improved by 3 orders of magnitude. The entire operational duration took only 1 hour with less costed reagents being consumed. It could make the high-throughput protein detection as sensitive as the reverse phase protein assays (RPPA) does. Conclusions The paper chip immunoassay could be performed qualitatively and semi-quantitatively to detect protein expression, and is more effective than that of traditional Western blot.

Key words: Key words：microfluidic paper-based immunoassay, Western Blot, MGMT, qualitative detection, relative quantitative detection