MXene nanosheets are promising to be ultrathin solid lubricant or interface solving the friction and wear problems of miniaturized equipment. Here, the frictional behaviors and adhesive properties of the Ti 3 C 2 , F-Ti 3 C 2 , and TMA-Ti 3 C 2 nanosheets were explored by atomic force microscope for the first time. The nanofrictional behavior of TMA-Ti 3 C 2 was significantly different from that of Ti 3 C 2 and F-Ti 3 C 2 . The friction of TMA-Ti 3 C 2 increased slightly and then decreased as the load decreased, leading to the appearance of a negative friction factor; the frictions of Ti 3 C 2 and F-Ti 3 C 2 decreased with decreasing load, resulting in positive friction factors. Meanwhile, because the surface of TMA-Ti 3 C 2 was more hydrophilic than that of Ti 3 C 2 and F-Ti 3 C 2 , the friction and adhesion of TMA-Ti 3 C 2 were greater than those of Ti 3 C 2 and F-Ti 3 C 2 . It indicated that the surface properties played an important role in the adhesion and friction. Hence, adjusting the surface properties of MXene nanosheets will provide a new direction for designing solid lubricants and nanointerfaces in micro-and nanoelectromechanical systems.

A microcantilever array biosensor based on a sandwich structure has been developed for simultaneously measuring two biomarkers carcinoembryonic antigen (CEA) and α-fetoprotein (AFP) via an optical readout techniquereal-time monitoring of the profile of cantilever. First, the aptamers of CEA and AFP were self-assembled on their respective cantilevers. After the adsorption of the mixture of CEA and AFP, further specific interaction was performed via the addition of the antibodies specific to each target. The compressive stress on the cantilever was generated by the aptamer–antigen–antibody sandwich structure formed on the gold surface, resulting in cantilever bending. The profile of cantilever could be monitored in real time. The relationship between the deflection value at the 90% position of the cantilever and the target concentration served as a calibration curve, and the detection sensitivity was 1.3 ng/mL for CEA and 0.6 ng/mL for AFP, respectively. This work demonstrated the ability of simultaneously measuring two biomarkers via a microcantilever array biosensor, giving great potential for further application in detecting several targets simultaneously for early clinical diagnosis.

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Studying the influence of nanomaterials on the microstructure and mechanical properties of cells is essential to guide the biological application of nanomaterials. In this article, the effect of the first...

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