Synergistic anticancer activity of fluorescent copper nanoclusters and cisplatin delivered through a hydrogel nanocarrier.

Highly fluorescent red copper nanoclusters (Cu NCs) were synthesized in aqueous medium in the presence of dihydrolipoic acid and poly(vinylpyrrolidone) (PVP). The Cu NCs, in solid form, were stable, retained their optical properties for a month, and could be redispersed for use when required. The NCs in aqueous medium exhibited pH-tunable reversible optical properties. The PVP stabilized NCs, when converted into hydrogel by cross-linking with poly(vinyl alcohol), delivered anticancer drug to cervical cancer (HeLa) cells, thereby inducing apoptotic cell death. The red emission properties of the Cu NCs in the hydrogel were used for optical imaging as well as for flow cytometric probe of cellular uptake. Cell viability assay, Caspase3 assay, and cell cycle analyses demonstrated that the Cu NCs present in the hydrogel composite exhibited synergy of action, along with the drug, cisplatin, against HeLa cells.