The dissolution of silver nanoparticles (AgNPs) to release Ag(I)(aq) is an important mechanism in potentiating AgNP cytotoxicity and imparting their antibacterial properties. However, AgNPs can undergo other simultaneous biophysicochemical transformations, such as protein adsorption, which can mediate AgNP dissolution behaviors. We report the comprehensive analysis of AgNP dissolution and protein adsorption behaviors with monolayer surface coverage of AgNPs by bovine serum albumin (BSA). AgNP dissolution rate constants, k dissolution , were quantified over several particle sizes (10, 20, and 40 nm) and BSA concentrations (0−2 nM) using linear sweep stripping voltammetry. Across all particle sizes, the dissolution rate constant increased with increasing BSA concentrations. However, protein-enhanced dissolution behaviors were most pronounced for 10 nm AgNPs, which exhibited 3.6-fold and 7.7-fold relative enhancement when compared to 20 and 40 nm AgNPs, respectively. Changes to AgNP surface properties upon interaction with BSA were monitored using dynamic light scattering and zeta potential measurements, while BSA−AgNP complex formation was evaluated using UV−vis spectroscopy and circular dichroism spectroscopy. A subtle increase in the BSA−AgNP association constant was observed with an increase in the AgNP size. Together, these results suggest that the AgNP size dependence of BSA-enhanced dissolution of AgNPs is possibly mediated through both displacement of Ag(I)(aq)-loaded BSA by excess protein in the bulk solution and minimized accessibility of the AgNP surface because of BSA adsorption.

Single entity electrochemistry experiments are typically motivated by the need to reveal how heterogeneity affects performance within inherently diverse nanoparticle populations. Here we show that a commonly used supporting electrode, tin‐doped indium oxide (ITO), can also play a significant role in creating heterogeneity in nanoparticle electrochemical responses. To investigate the impact of the substrate, we optically monitored the electrodissolution kinetics of gold nanoparticles on ITO thin films with similar resistivity from two different suppliers. The ITO from the two suppliers showed marked differences in the gold electrodissolution kinetics, with ITO from one of the suppliers even producing poor sample‐to‐sample reproducibility across substrates within the same lot number. The role of nanoparticle size and surface effects were accounted for in our analysis to validate that the observed heterogeneity is dominated by the ITO electrodes. The results show that the role of the supporting electrode cannot be ignored when performing single entity structure‐function studies.

The aggregation of silver nanoparticles (AgNPs) as they encounter biological and environmental systems can dictate their fate and transport. Here, we present a rapid, affordable, and robust analytical method for...

Linear sweep stripping voltammetry (LSSV) is demonstrated as a sensitive, rapid, and cost-efficient analytical technique for the quantification of silver nanoparticle (AgNP) dissolution rates in simulated sweat. LSSV does not require the extensive sample preparation (e.g., ultrafiltration or centrifugation) needed by more commonly employed techniques, such as atomic spectroscopy. The limit of detection (LOD) of Ag­(I)­(aq) was 14 ± 6 μg L–1, and measured dissolution rate constants, k dissolution, varied from 0.0168–0.1524 h–1, depending on solution conditions. These values are comparable and agree well with those determined by others in the literature using atomic spectroscopy. Importantly, LSSV had the necessary sensitivity to distinguish the effects of SSW solution conditions on AgNP dissolution rates. Specifically, enhanced dissolution rates were observed with decreased pH and with increased NaCl concentration. The colloidal stability of AgNPs in SSW solutions was also characterized using dynamic light scattering (DLS), ζ potential, and quantitative UV–vis spectroscopy measurements. An increase in AgNP aggregation rate was observed with increased NaCl concentration in SSW, suggesting that the enhancement in AgNP dissolution is driven by the large Cl/Ag ratio, even as the AgNPs undergo significant aggregation.