Effects of preparation on catalytic, magnetic and hybrid micromotors on their functional features and application in gastric cancer biomarker detection

Artificial micromotors evolve to improve multitasking performance in different research areas, and different power sources are combined to give rise to hybrid micromotors. Such combinations can alter physical features and influence movement aspects that until now have not been taken into account. Here, we comparatively studied how physical features of magnetic (erGO/Ni), catalytic (erGO/Pt), or dual propulsion (erGO/Pt-Ni and its inverted form erGO/Ni-Pt) micromotors can influence direction and speed. The results showed that erGO/Pt and erGO/Ni microtubes presented different growth modes dependent on experimental conditions. For the hybrid form, similar features were observed but thicker and shorter than their individual versions. The catalytic motion comparison demonstrated that the main movement pattern was circular, and erGO/Pt micromotors were faster than the hybrid form, reaching speeds up to 360 mu m s(-1). The addition of a third material decreased significantly the speed especially when nickel was in the last layer, demonstrating that the order in which metallic elements are deposited is relevant and influences the speed. The erGO/Pt microtubes were selected to detect Reprimo, a gastric cancer biomarker. The detection assay (static or catalytic conditions) relies on the turnoff/turn-on fluorescence recovery due to the hybridization process between the Reprimo probe tagged with a fluorescein amidine dye and target biomarker Reprimo ssDNA, followed by its detachment from microtube. The catalytic detection results have shown to possess great selectivity as well as good reproducibility and can become a promising strategy for qualitative or quantitative detection of Reprimo or other circulant cancer biomarkers based on DNA.