Novel Membrane Detector Based on Smart Nanogels for Ultrasensitive Detection of Trace Threat Substances

A novel membrane detector is developed by a facile strategy combining commercialized membrane and smart nanogels for ultrasensitive and highly selective real-time detection of trace threat substances. On the basis of nanogel filtration and polydopamine adhesion, the membrane detector is fabricated by simply immobilizing smart nanogels onto the multiple pores of a commercialized membrane as the nanosensors and nanovalves. This is demonstrated by incorporating Pb²⁺-responsive poly( N-isopropylacrylamide- co-acryloylamidobenzo-18-crown-6) nanogels in the straight pores of a commercialized polycarbonate membrane for ultrasensitive and highly selective real-time detection of trace Pb²⁺. When selectively recognizing the Pb²⁺ in solution, the smart nanogels in the membrane pores swell, which lead to trans-membrane flux change. Quantitative detection of Pb²⁺ concentration can be achieved by simply measuring the flow rate of the trans-membrane flow. Due to the multiple nanochannels of nanogel-immobilized pores in the membrane for Pb²⁺ sensing and flux regulating, ultrasensitive and highly selective real-time detection of trace Pb²⁺ with concentration as low as 10^-10 mol L^-1 can be achieved. The nanogel-immobilized membrane detector offers a flexible platform to create versatile new membrane detectors by incorporating diverse smart nanogels for ultrasensitive and highly selective real-time detection of different trace threat substances.