Selective Interfacial Assembled Asymmetric Porous Nanomotors as Maneuverable Labels for Boosting Capture and Ultrasensitive Detection.

Rational integration of autonomous motion and multifunctional labels into immunosensors represents a highly effective strategy for markedly enhancing the antigen capture efficiency and improving the detection sensitivity. Here, smart asymmetric porous nanomotors (FPSP) are designed and fabricated through a selective interfacial assembly strategy, demonstrating magnetic, photothermal, porous, and catalytic activity. Upon near-infrared irradiation, the mesoporous dopamine shell on the FPSP establishes a localized thermal gradient that propels the nanomotor through thermophoretic forces. FPSP nanomotor labels overcome the low sensitivity of immunosensors in early stage detection caused by low analyte concentrations and complex sample matrices. The carbohydrate antigen 153 (CA153) for breast cancer is chosen as an example. This motion enhances the collision probability between FPSP-antibody and CA153, thereby increasing the capture efficiency compared to the static label 95.8%. FPSP exhibits superb colorimetric signal brightness, fast motion, high peroxidase-mimicking activity, and magnetic separation. Integration of FPSP into a dual-antibody sandwich immunosensor enabled ultrasensitive CA153 quantification, achieving the detection limit of 0.0021 U mL, which is approximately 316.5-fold higher than that of static label-based immunosensors. This novel immunosensor significantly advances biosensing capabilities, offering promising applications in cancer diagnostics, environmental monitoring, and other areas requiring high-sensitivity detection.