Detection Of MiRNAs With Silicon Nanowire Biosensors

Background:In the past decade the diagnostic and prognostic value of microRNAs in a variety of cancers and other diseases attract lots of attention. However, the routine detecting methods require labeling or amplification, which include a lot of procedures. The novel silicon nanowire (SiNW) biosensors have advantages in molecular detection because of their high sensitivity and fast response. This project aims to develop SiNW arrays which can quickly and directly detect miRNAs.Methods:SiNW biosensors were fabricated through photolithography with polysilicon. Functionalization of the SiNW devices was carried out by using2%(3-Aminopropyl) triethoxysilane (APTES) to convert surface silanol groups to amines followed by treatment of1.25%glutaraldehyde, thus single-strand probe can be attached onto the aldehyde-modified surface. After ssDNA and miRNA hybridization, SiNW devices can be used to detect standard Let-7b sample and snRNA U6in total RNA extracted from HepG2by comparing the difference of resistance value before and after the test.Results:SiNW arrays can be applied to detect standard Let-7b sample with a detection limitation of1fM and distinguish perfect match from mismatch meanwhile. Furthermore, these SiNW arrays can detect snRNA U6in total RNA extracted from HepG2with a concentration limitation of0.2μg/mL.Conclusion:These SiNW arrays can detect at least1fM standard Let-7b sample and0.2μg/mL snRNA U6in total RNA from HepG2. We will look forward to better results through improving project design.