In situ synthesized graphene oxide-silver nanocomposite shows cell-type-dependent modulation of cytotoxicity in human
Diego Wiechers1,2,3, Ana Júlia Ferreira Fagundes1, Diniz Luiz Portugal de Sousa1
1Biological Metrology Division, National Institute of Metrology Quality and Technology, Rio de Janeiro, Brazil.
Purpose:
Graphene oxide-silver nanoparticle (GO-AgNP) nanocomposites have attracted interest due to the ability of graphene oxide to act as a support for silver nanoparticles and thereby influence their physicochemical and in vitro biological behavior; however, comparative studies integrating physicochemical characterization with cytotoxicity assessment in human cell models remain limited. This study aimed to synthesize a GO-AgNP hybrid and evaluate its effects, along with pristine GO and free AgNPs, in human retinal (ARPE-19), glioblastoma (U-87 MG), and hepatic (HepG2) cell models.
Methods:
GO was prepared using a Hummers method, while AgNPs and GO-AgNPs were synthesized via a tannic-acid/citrate reduction route. The materials were characterized by UV-Vis, Raman, FTIR, AFM, SEM/TEM, ICP OES, and spICP-MS. Cytotoxicity was assessed after 72 h using MTT and LDH assays across all three cell models, and IC₅₀ values were determined for HepG2 cells.
Results:
Physicochemical analyses confirmed successful AgNP nucleation on GO sheets, evidenced by the emergence of the 418 nm plasmonic band, reduction of the AD/AG Raman ratio, attenuation and shifting of oxygen-related FTIR bands, and uniformly dispersed AgNPs with a mean diameter of ~ 47 nm. Biologically, GO remained largely biocompatible, whereas free AgNPs induced strong, dose-dependent metabolic impairment and membrane damage. GO-AgNPs exhibited an intermediate and cell-type-dependent toxicity pattern, with strong attenuation of AgNP effects in ARPE-19 cells, partial attenuation in U-87 MG cells, and a moderate reduction in HepG2 cells. In HepG2, IC₅₀ values followed the expected potency order: AgNP (5.3 µg/mL), GO-AgNP (33.4 µg/mL), while GO did not reach 50% inhibition within the tested concentration range.
Conclusion:
The synthesized GO-AgNP nanocomposites display well-defined structural features and substantially reduced cytotoxicity compared with free AgNPs, although the extent of attenuation varies by cell lineage. These findings indicate that GO anchoring modulates silver bioactivity in a cell-type-dependent manner under the present in vitro conditions.
