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Description
The widespread presence of polystyrene nanoplastics (PS-NPs) in aquatic environments presents critical environmental and health challenges, driving the demand for highly sensitive detection platforms. This work presents a silver nanoparticle-functionalized silicon wire (AgNP-SiW) sensor for the label-free detection of PS-NPs in water samples. The sensor is fabricated via a top-down approach utilizing a silicon-on-insulator (SOI) substrate, standard photolithography, and plasma etching processes. The physical structure of the fabricated SiW and the successful electrodeposition of AgNPs were verified using Field Emission Scanning Electron Microscopy (FESEM), UV-Vis spectroscopy, and Energy-Dispersive X-ray (EDX) spectroscopy. The sensing mechanism relies on surface charge modulation and localized electrical property changes occurring when PS-NPs interact with the AgNP-functionalized SiW interface. Electrical characterization demonstrates that the device exhibits systematic, progressive shifts in its current-voltage transport curves across baseline, control, and varying concentrations of 100 nm PS-NPs. Each concentration yields an incremental change in the current response, allowing the sensor to effectively detect and differentiate varied concentration levels of nanoplastics in aqueous samples. These findings underline the sensor's potential as a high-performance tool for environmental monitoring and water quality assessment.
