Insight into the Effect of Stabilizers on Anticancer and Antibacterial Activity of AgBiS2 Nanomaterial

The near‐infrared (NIR) light‐absorbing AgBiS2 nanoparticles can be excited by single‐wavelength light, which is the primary characteristic of a photo responsive platform. Chemical synthesis of nanomaterials inevitably requires long‐chain organic surfactants or polymers to stabilize them in the nano regime. These stabilizing molecules barricade the interaction of nanomaterials with biological cells. We have produced stabilizer‐free (sf‐AgBiS2) and polymer‐coated (PEG‐AgBiS2) nanoparticles; and assessed their NIR mediated anticancer and antibacterial activity to evaluate the effect of stabilizers. sf‐AgBiS2 showed better antibacterial activity against Gram‐positive Staphylococcus aureus (S. aureus) and displayed excellent cytotoxicity against HeLa cells and live 3‐D tumour spheroids compared to PEG‐AgBiS2 both in presence and absence of NIR radiation. The photothermal therapy (PTT) results illustrated the tumour ablation ability of sf‐AgBiS2, which converted light into heat effectively up to 53.3 °C under NIR irradiation. This work demonstrates the importance of synthesizing stabilizer‐free nanoparticles to produce safe and highly active PTT agents. The physicochemical interaction of nanoparticles with biological systems differs in the presence and absence of stabilizers (surfactant or polymer molecules) used during their synthesis. In this study, the AgBiS2 nanoparticles produced without stabilizing molecules demonstrated better anticancer activity than the polymer‐coated nanoparticles. This work provides insight into the importance of the clean surface of nanoparticles in nanomedicine.