Smartphone-Integrated resorcinarene macrocycle capped silver nanoparticles (RMF-AgNPs) probe for enhanced La(III) detection in diverse environments

Abstract

The demand for precise and responsive detection of Lanthanum (La(III)) is critical in key areas such as environmental monitoring, biomedical research, and industrial processes, underscoring the need for advanced sensor technologies. This research reports an efficient and cost-effective preparation of resorcinarene macrocycle framework (RMF) capped silver nanoparticles (RMF-AgNPs). These nanoparticles were then applied as a novel sensor for La(III), demonstrating dual functionality: they act as a colorimetric sensor and a paper-based probe. Unique in its class, the sensor excels in detecting La(III) at ultra-low concentrations, unaffected by other ions, and undergoes a significant color transition from yellow to grey in response to La(III) presence. This change is linked to the localized surface plasmon resonance (LSPR) absorbance alteration. Extensive analytical methods like FTIR, XPS, AFM, FESEM, DLS, Zeta potential, and UV–Vis spectroscopy confirmed that the sensor operates by aggregating nanoparticles induced by La(III). Adding to its practicality, we incorporated a smartphone interface with the paper-based sensor, enhancing its utility for on-the-spot, real-time detection. The sensor's efficacy was validated across various samples, including soil, rock, urine, drinking water, and industrial effluent, showing its versatility. With detection limits of 15 nM (colorimetric) and 280 nM (paper-based), and linear dynamic ranges from 0.05 to 100 µM and 0.5–100 µM respectively, this sensor marks a significant advancement, effectively bridging lab-based detection with field application needs.