Homologous miRNA Analyses Using a Combinatorial Nanosensor Array with Two-Dimensional Nanoparticles

A novel combinatorial nanosensor array for miRNA analyses was assembled using the intrinsic noncovalent interactions of unmodified two-dimensional nanoparticles. Discrimination of nine miRNA analogues with as little as a single nucleotide difference was demonstrated under 2 h. All nine targets were identified simultaneously with 95% confidence. The developed nanotechnology offered identification and quantification of unknown targets with unknown concentration. Discrimination of target mixtures from low-to-high ratios was demonstrated. The DNA and RNA analogues of targets were identified using the combinatorial sensory approach. Identification of a target in a complex biological matrix prepared with human urine was demonstrated. The nanosensor array was put together using 15 nanoassemblies (2D-NAs) constructed using three two-dimensional nanoparticles (2D-nps: WS 2, MoS 2, and nanographene oxide (nGO)) and five rationally designed fluorescently labeled 15-nt-long ssDNAs (probes). In this approach, each target has only a small yet varying degree of complementarity with each of the five probes adsorbed on the 2D-np surface. The probes in each 2D-NA are desorbed from the surface by each target with a different degree that was recorded with fluorescence recovery measurements. The fluorescence data set was processed by partial least squares discriminant analysis (PLSDA), and each target was discriminated successfully. This new approach has a number of advantages over the classical bind-and-release model, typically used for 2D-np based biosensors, and opens greater detection opportunities with 2D-nps.