Lanolin in implantation of luminous polymer dots for environmental application as metal probes

Polymer dots (PDs) have become one of the potential fluorescent nanomaterials in environmental sensing because they are low-toxicity, tunable optical nanomaterials, and are cost-effective. Herein, a green and facile hydrothermal strategy was formed to nucleate luminous PDs with lanolin, while the effect of dissolution precursors (sodium hydroxide, formic acid, and dimethyl formamide) on PDs nucleation was investigated. NaOH use produced the smallest PDs (3.7 ± 1.4 nm) with high dispersion (-29.3 mV) and maximum physical stability. Dissolution with formic acid generated optically inactive nanostructures (emission at 5.6), whereas NaOH yielded the highest emission intensity (317.7). The prepared PDs were applied as metal probes for lead and mercury detection. Increasing Hg²⁺ concentration from 10 mM to 100 mM reduced emission from 284.9 to 42.9. Similarly, Pb²⁺ concentration increase from 20 mM to 160 mM decreased emission from 296.2 to 28.1. The data revealed higher sensitivity toward Hg²⁺ (R² = 0.99) at low concentrations (10-40 mM) and toward Pb²⁺ (R² = 0.98) at higher concentrations (80-160 mM). These results prove that lanolin-based PDs could be effectively used as fluorescent probes in detecting toxic heavy metals in a sustainable and eco-friendly way, which implies their usage in sustainable environmental monitoring systems.