Molybdenum Disulfide‐Based Tubular Microengines: Toward Biomedical Applications

2D molybdenum disulfide (MoS₂) is herein explored as an advanced surface material in the fabrication of powerful tubular microengines. The new catalytic self‐propelled open‐tube bilayer microengines have been fabricated using a template electrodeposition and couple the unique properties of sp² hybridized MoS₂ with highly reactive inner granular Pt catalytic structures. The MoS₂/metal microengines display extremely efficient bubble propulsion, reflecting the granular structure of the inner catalytic platinum or gold layers (compared to the smooth metal surfaces of common micromotors). The efficient movement of functionalized MoS₂ micromotors can address challenges imposed by slow mass transport processes involved in various applications of MoS_2. The delocalized electron network of the MoS₂ outer layer facilitates π–π stacking interactions and endows the tubular microengines with a diverse array of capabilities. These are demonstrated here for efficient loading and release of the drug doxorubicin, and rapid and sensitive “OFF–ON” fluorescent detection of important nucleic acids (miRNA‐21) and proteins (thrombin) using microengines modified with dye‐labeled single‐stranded DNA and aptamer, respectively. Such coupling of the attractive capabilities of 2D‐MoS₂ nanosheets with rapidly moving microengines provides an opportunity to develop multifunctional micromachines for diverse biomedical applications ranging from efficient drug delivery to the detection of important bioanalytes.