C57BL/6 Mouse Primary Liver Fibroblasts

Biosafety Evaluation of a Graphene Oxide-Captopril Sustained-Release System

Captopril (CAPT), a widely prescribed antihypertensive, faces limitations of rapid clearance and poor aqueous solubility. Graphene oxide (GO) was explored as a nanocarrier to enable sustained CAPT delivery, but its biosafety-particularly at high concentrations and large lateral sizes-requires rigorous validation. Liu's team assessed the cytotoxicity of a GO-CAPT delivery system across three biological dimensions: cell proliferation, structural integrity, and cell death modality, using human colorectal adenocarcinoma (Caco-2) cells and primary mouse hepatic fibroblasts.

Proliferation assays using the WST-1 kit showed that even at a high GO concentration of 50 mg/L, the cell survival rate in Caco-2 cells remained 92.38%, compared to 99.58% in the deionized water (DIW) control, representing only a 7.2% reduction (Fig. 1A). The GO-CAPT formulation showed a minimal 2.59% reduction versus control (96.99% viability) and displayed no statistically significant impact. Identical trends were observed in primary mouse liver fibroblasts (Fig. 1B), confirming negligible effects on cell proliferation.

To evaluate structural integrity, lactate dehydrogenase (LDH) release was measured. In Caco-2 cells, cytotoxicity in the DIW control was 0.89%, while GO at 50 mg/L induced only 1.48% cytotoxicity-a 0.59% difference (Fig. 2A). The GO-CAPT group exhibited 1.08% cytotoxicity, differing by just 0.19% from the control. Again, primary fibroblasts mirrored this low-impact profile (Fig. 2B). These results demonstrate that GO with a large lateral size (1-2 µm) and concentrations up to 50 mg/L does not significantly impair cell proliferation or membrane integrity. Furthermore, the GO-CAPT delivery system exhibits excellent cytocompatibility, supporting its potential as a safe and effective platform for sustained captopril release in biomedical applications.