On-chip single-cell-based gene expression analysis using gold nano-particles

The authors have developed a novel method to measure the quantitative amount of mRNA expression in individual cells keeping their spatial distributions in the cell without any amplification process like PCR. In this method, a set of different sizes of gold nanoparticles attached with different probe-DNA respectively were used as a set of probes to detect different mRNAs existing in a cell. At first, the optimum condition of the immobilization of probe-DNA onto the gold nanoparticle surface was examined. Next, the selectivity of the probe-DNA immobilized onto the nanoparticle was tested using complementary oligonucleotide molecules. We confirmed the several different kinds of gold nanoparticle probes were hybridized with target oligonucleotides having complementary sequences with almost 100% selectively. For the counting and distinguishing each of the gold nanoparticles, we used two different methods and compared: one is atomic force microscopy and the other is scanning electron microscopy. Quantitative detection of mRNAs in individual cells keeping their spatial distributions was then examined using the gold nanoparticle-based detection system. In this meeting, we will present the results and will discuss about the potential and problems of this method for the single-cell-based quantitative expression analysis.