Visible fluorescent sensing of Cu ions in urine by reusable chitosan/l-histidine-stabilized silicon nanoparticles integrated thin layer chromatography sheet.

This study reports a facile approach for the fabrication of chitosan (CS, biopolymer)- and l-histidine (L-His, biomolecule)-stabilized self-assembled silicon nanoparticles (SiNPs) for sensing Cu ions. Approached method yielded 3.8 ± 0.04 nm size CS/L-His-SiNPs particles, with high stability against harsh pH and temperature conditions. Besides, CS/L-His-SiNPs highly selective to Copper amongst different metal ions tested (Fe, Mg, Al, Cr, Cr, Cu, Mn, Cd, Pb, Zn, Hg, Ca, Li, Po, As, As). As compared to the blank-SiNPs (LOD = 96.49 ± 0.223 μM) and CS-SiNPs (LOD = 33.35 ± 1.004 μM); L-His ligand, enhanced the sensitivity of the CS/L-His-SiNPs toward Cu with remarkable LOD value of 55.02 ± 0.42 nM. Applicability of CS/L-His-SiNPs was evaluated by coating CS/L-His-SiNPs on thin layer chromatography (TLC) sheets, CS/L-His-SiNPs-TLC sheets exhibited significant sensing capacity toward Cu ions, with a detection range of 4.0-900 μM, making them suitable for on-site analysis of Cu ions from both environmental and clinical samples. Finally, Cu sensing practicality of CS/L-His-SiNPs-TLC sheets were challenged against real human urine samples. Expressively, CS/L-His-SiNPs-TLC sheets could be regenerated using ethylenediaminetetraacetic acid (EDTA), without losing their photostability, and can be reused further.