Water-Soluble One-Pot Green Synthesis of Collagen Stabilized Copper Nanoclusters for Selective Fluorescent Turn-Off...

The affordable and readily available 3d metal copper with collagen as a stabilizing agent demonstrates the effective production of fluorescent copper nanoclusters. A facile one-pot green approach has been developed to obtain collagen-stabilized fluorescent copper nanoclusters (Collagen-CuNCs). The fluorescent Collagen-CuNCs were characterized by different methods, such as HR-TEM, FT-IR, XPS, UV-Vis, and fluorescence spectroscopy. The metal ions selectivity of Collagen-CuNCs was examined in an aqueous medium by adding Ca²⁺, Hg²⁺, Cd²⁺, Pb²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Fe³⁺, Cr³⁺, Al³⁺, and Fe²⁺ ions. Ferric ions selectively quenched the fluorescence emission of Collagen-CuNCs (λ_em = 480 nm), among other tested metal ions. The fluorescence quenching mechanism was investigated using Stern-Volmer analysis and time-resolved fluorescence. With a nanomolar detection limit of 0.14 nM, the developed nanoprobe Collagen-CuNCs was employed to quantify Fe³⁺ ions in spiked blood serum.