BACKGROUND: Several issues have been raised emphasizing the harmful toxic effects of metal nanoparticles towards biological systems. Search of biological nanoparticles with excellent biocompatibility and bioavailability could address this problem.

METHODS: Fibrin nanoparticles (FNP) were prepared using a novel technique and characterized for their physico-chemical properties. In vitro studies were performed to examine cytotoxicity and cellular uptake of FNP. Innate immune response to FNP was studied by (i) estimating in vitro generation of complement split products, C3a and C4d and (ii) in vivo expression of pro-inflammatory cytokines, TNF-α, IL-1 and IL-6. In vivo biodistribution study was carried out by intravenous administration of FITC-labelled FNP in mice.

RESULTS: FNP were spherical with size ranging from 25 to 28nm. In vitro studies proved the biocompatibility of the nanoparticles, with their distribution across the cytoplasm and nucleus of treated cells. Complement activation studies showed insignificant increase in the level of C3a when compared with positive control. RT-PCR results revealed significant upregulation of TNF-α and downregulation of IL-6 cytokines after 6h of FNP administration. In vivo biodistribution studies showed moderate blood circulation time, with predominant distribution of nanoparticles in the liver followed by the lungs, kidney and spleen. Haematology, serum biochemistry, and histopathology analyses demonstrated that FNP were non-toxic.

CONCLUSION: Owing to their small size, low cost, ease of preparation and excellent biocompatibility, FNP might be a promising novel material for drug delivery applications.

GENERAL SIGNIFICANCE: Our results demonstrate the safe and promising use of FNP for biomedical applications.