Determination of the bioavailability of zinc oxide nanoparticles using ICP-AES and associated toxicity

Advancement in nanotechnology has brought abundant number of products and materials in multiple fields including biomedicine owing to their unique physico-chemical properties. This further necessitates toxicity assessment of nanoparticles (NPs) before they are employed for product fabrication, medicinal, environmental or industrial purposes. Zinc oxide nanoparticles (ZnONPs) belong to the category of metal oxide NPs and hold quite a lot of possibilities to be applied in aforementioned scenarios. Present study addresses the probable outcomes of bio-nano interaction of ZnONPs with healthy adult Wistar rats. Sphere head shaped ZnONPs were synthesized via wet chemical method. Physico-chemical characterization was performed using number of sophisticated techniques including HR-TEM, Zeta potential analysis, TGA and XRD. Size of the particles was found to be 43 nm and ensured homogenous distribution with high purity. For in vivo studies, as synthesized NPs were administered into rats via intravenous (i.v.) and intraperitoneal (i.p.) routes. Animals were sacrificed on 3rd, 14th and 21st day of exposure. Metabolically relevant tissues like brain, liver, kidneys and spleen were isolated and analyzed for different parameters like gross pathology, haematology, neurotoxicity, target organ toxicity, immunotoxicity etc. Results suggests that ZnONPs did not elicit significant toxic responses in rat except a few anomalies with histology, ion content and antioxidant system within liver; thereby confirming potent hepatotoxicity. Hence the study recommends adopting surface functionalization strategies for reducing toxic response of ZnONPs during various application rationales.