Self-Propelled Janus Mesoporous Micromotor for Enhanced MicroRNA Capture and Amplified Detection in Complex Biological Samples.

The slow mass transport of the target molecule essentially limits the biosensing performance. Here, we report a Janus mesoporous microsphere/Pt-based (meso-MS/Pt) nanostructure with greatly enhanced target transport and accelerated recognition process for microRNA (miRNA) amplified detection in complex biological samples. The mesoporous MS was synthesized via double emulsion interfacial polymerization, and Pt nanoparticles (PtNPs) were deposited on the half-MS surface to construct Janus meso-MS/Pt micromotor. The heterogeneous meso-MS/Pt with a large surface available was attached to an entropy-driven DNA recognition system, termed meso-MS/Pt/DNA, and the tremendous pores network was beneficial to enhanced receptor-target interaction. It enabled moving around complex biological samples to greatly enhance target miRNA mass transport and accelerate recognition procedure due to the self-diffusiophoretic propulsion. Coupling with the entropy-driven signal amplification, extremely sensitive miRNA detection in Dulbecco's modified Eagle medium (DMEM), and cell lysate without preparatory and washing steps was realized. Given the free preparatory and washing steps, fast mass transport, and amplified capability, the meso-MS/Pt/DNA micromotor provides a promising method for miRNAs analysis in real biological samples.