Preparation of surface-modified PLGA nanoparticles containing carbon quantum dots: insights from C6 cell line assays

In this study, carbon quantum dot (CQD)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were prepared, and their surfaces were modified with tween 20, tween 80, poloxamer 188, or poloxamer 407. The physicochemical properties, cytotoxicity, and cellular uptake of the NPs were subsequently evaluated using the C6 glioblastoma cell line. The NPs were prepared via the nanoprecipitation method, and surface modifications were achieved through physical adsorption. The physicochemical characteristics of the NPs including mean diameter, zeta potential, and in vitro release of CQDs, were assessed. Hemolysis and in vitro studies, including MTT assay, apoptosis/necrosis assay, and cellular uptake, were conducted. Poloxamer-coated NPs demonstrated a more sustained release of CQDs compared to tween-coated NPs. Hemolysis and cytotoxicity were concentration-dependent, with poloxamer-coated NPs exhibiting lower hemolysis at 2 mg/mL and reduced cytotoxicity at higher concentrations. All formulations were effectively internalized by C6 cells, and poloxamer 407-coated NPs showed the lowest rate of necrosis. Poloxamer-coated NPs exhibited favorable characteristics, including sustained release, lower toxicity, and enhanced cellular uptake. These findings support their potential as effective surface modifiers in the development of multifunctional nanocarriers for brain-targeted drug delivery.