Preparation of self-propelled Cu-Pt micromotors and their application in miRNA monitoring

Abstract

Self-propelled catalytic micromotors offer considerable promise in terms of many applications. Catalyticmicromotors are strongly influenced by the presence and concentration of specific ions and chemicals in the environment,making them useful as sensors and actuators. In this work, copper (Cu)-platinum (Pt) micromotors were fabricatedby using the magnetron sputtering method for the first time in the literature and their applications based on thedetection of miRNA-21 were evaluated. We analyzed the dependence of the mobility of Cu-Pt micromotors usingdifferent concentrations of hydrogen peroxide (H2 O2). The presence of surfactants in the environment is also importantfor the movement of the micromotors. Thus, we studied the effect of three different surfactants: anionic as sodiumdodecyl sulfate (SDS), cationic as cetyltrimethylammonium bromide (CTAB), and nonionic as Triton X-100. Cu-Ptmicromotor motion was observed even at very low concentrations of surfactant (0.01%) and hydrogen peroxide (0.25%).miRNAs have been regarded as biomarker candidates in early diagnosis. Our sensing strategy relied on dye-labeledsingle-stranded DNA immobilization onto Cu-Pt micromotors that recognize the target miRNA-21. The changes in thefluorescence intensity as well as the changes in the speed of micromotors were examined before and after hybridization.