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
techniquereal-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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