Cytotoxicity and Cellular Responses of Gold Nanorods to Smooth Muscle Cells Dependent on Surface Chemistry Coupled Action

Gold nanorods (AuNRs), with their unique physicochemical properties, are recognized as promising materials for biomedical applications. Chemical modification of their surfaces is attracting increasing attention with regard to cytotoxicity and cellular uptake. Herein, the toxicological effects of three types of polymer-coated AuNRs, which are cetyltrimethylammonium bromide-coated AuNRs, polystyrene sulphonate-coated AuNRs, and poly(diallyldimethyl ammonium chloride-coated AuNRs (PDDAC-AuNRs), on vascular smooth muscle cells (VSMCs) are investigated. The results show significantly different effects on VSMCs with different surface coatings. PDDAC-AuNRs, which were nontoxic in cancer cells in previous reports, display extreme toxicity to VSMCs. Initial contact between AuNRs and cell membranes is the important step in AuNRs cellular uptake. Force spectroscopy based on atomic force microscopy is exploited to study interactions between AuNRs and VSMCs membrane in the absence or presence of a corona on the AuNRs surface. The results show that the binding force and binding probability between AuNRs and membranes are closely related to cytotoxicity and cellular responses. These findings highlight the importance of assessing nanoparticle cytotoxicity in somatic cells for medical applications.