Hepatic bioavailability and cellular response to microfluidic synthesized FITC@p(GMA-EGDMA) nanoparticles

Fluorescent polymeric nanoparticles have emerged as versatile tools in biomedical imaging due to their tunable optical properties and potential for biological integration. In this study, fluorescein isothiocyanate-labeled poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) nanoparticles synthesized via microfluidic methods were evaluated for their biocompatibility, cytotoxicity, cellular uptake, and functional effects in HepG2 human hepatocellular carcinoma cells, a widely used model for assessing nanoparticle biocompatibility and hepatic metabolism. A concentration range of 0–100 µg/mL was applied over 24, 48, and 72 hours. In vitro cytotoxicity, assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, revealed significant dose- and time-dependent effects on HepG2 cell viability. Notably, at 24 hours all tested concentrations, including 100 µg/mL, maintained cell survival above the 70% non-cytotoxic threshold defined by ISO 10993-5:2009, whereas prolonged exposure at 100 µg/mL resulted in values below this limit. Fluorescence microscopy confirmed dose-dependent cellular association of the nanoparticles without compromising cell morphology. Acridine Orange/Propidium Iodide staining corroborated the cytotoxicity profile by demonstrating dose-dependent increases in membrane damage, consistent with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay results. Furthermore, a scratch wound assay demonstrated impaired migration capacity at ≥50 µg/mL after 24 hours, indicating a functional cellular response even in the absence of overt cytotoxicity. Stability assessments showed preserved colloidal and structural integrity over 72 hours, although fluorescence intensity declined over time. Collectively, the results support the use of fluorescein-labeled poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) nanoparticles as biocompatible and traceable platforms for short- to mid-term in vitro imaging and drug delivery applications, with suggested operational concentrations below 50 µg/mL to ensure minimal functional interference.