Table 4.

In vitro toxicity studies of commonly used biodegradable polymers in medical applications

Polymer	Assay	Results	Reference
PEG (positively and negatively charged)	• MTT cell proliferation assay in NR8383 and Caco-2 cells • Mitochondrial membrane potential induction of reactive oxygen species production • ATP depletion and TNF-α release	• Positively charged nanoparticles of 45 nm were more cytotoxic than 90 nm nanoparticles • Negatively charged nanoparticles of both 45 nm and 90 nm did not induce significant cytotoxic responses	174
Polyvinyl alcohol, PEG, and polyvinyl chloride	• MTT test in MRC5 human lung fibroblasts	• Polyvinyl chloride and PEG were not cytotoxic • Polyvinyl alcohol did not inhibit cell proliferation and did not lead to morphology changes	175
PLGA, poly(ε-carbobenzoxy-L-lysine)	• MTT assay in rat endothelial cells and human umbilical vein endothelial cells	• No toxicity was seen in cells exposed to PLGA-poly(e-carbobenzoxy-L-lysine) or PLGA at concentrations or time points assessed	176
Chitosan	• Zebrafish embryo model: embryos were exposed to chitosan nanoparticles for 96 hours, and dose-dependent inhibition of embryo hatching was determined	• A significant decrease in hatching rate was observed at 20 mg/L and 40 mg/L concentrations of 340 nm chitosan nanoparticles • A significant decrease in hatching rate was observed at 30 mg/L and 40 mg/L of 200 nm chitosan nanoparticles • At higher concentrations, chitosan nanoparticles were toxic to the zebrafish embryos	177
	• MTT assay in Caco-2 cell toxicity	• Fucoidan-chitosan, in non-nanoparticle form, decreased cell viability of Caco-2 cells • Fucoidan-chitosan nanoparticles (250, 500, and 1,000 μg/mL) were not cytotoxic	178

Abbreviations: PEG, poly(ethylene glycol); MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; ATP, adenosine triphosphate; TNF-α, tumor necrosis factor-alpha; PLGA, poly(lactic-co-glycolic acid); MRC5, human fetal lung fibroblast cells; Caco-2, human colon carcinoma cells.