Analytical-Based Methodologies for Examining the In Vitro Absorption, Distribution, Metabolism, and Elimination (ADME) of Silver Nanoparticles

Abstract

The clinical applications of silver nanoparticles (AgNPs) remain limited due to the lack of well-established methodologies for studying their nanokinetics. Hereby, the primary goal is to adapt a suite of analytical-based methodologies for examining the in vitro absorption, distribution, metabolism, and elimination of AgNPs. Vero 76 and HEK 293 cells are exposed to ≈10-nm spherical AgNPs⁺ and AgNPs^- at relevant concentrations (0-300 µg mL^-1 ) and times (4-48 h). Absorption: Inductively coupled plasma optical emission spectroscopy (ICP-OES) demonstrates that the two AgNP formulations are not bioequivalent. For example, different bioavailabilities (C_maximum < 20.7 ± 4% and 6.82 ± 0.4%), absorption times (T_maximum > 48 and ≈24 h), and absorption rate laws (first- and zeroth-order at 300 µg mL^-1 ) are determined in Vero 76 for AgNPs⁺ and AgNPs^- , respectively. Distribution: Raman and CytoViva hyperspectral imaging show different cellular localizations for AgNPs⁺ and AgNPs^- . Metabolism: Cloud point extraction (CPE)-tangential flow filtration (TFF) reveal that ≤ 11% ± 4% of the administered, sublethal AgNPs release Ag⁺ and contribute to the observed cytotoxicity. Elimination: ICP-OES-CPE suggests that AgNPs are cleared via exocytosis.

Keywords: CPE-TFF; ICP-OES; Raman and CytoViva hyperspectral imaging; nanokinetics; silver nanoparticles.