Chitosan grafting onto single-walled carbon nanotubes increased their stability and reduced the toxicity in vivo (catfish) model.

The present work was aimed to develop the tissue benign, modified acid-functionalized single-walled carbon nanotube (COOH-SWCNT) chitosan (CS) hybrid (COOH-SWCNT-CS). Chitosan-nanotube hybrids were characterized by Fourier-transform infrared spectroscopy (FTIR), Thermogravimetry Analysis (TGA), Raman spectroscopy, Emission Gun-Scanning Electron Microscopes (FEG-SEM), Transmission Electron Microscopy (TEM) and Energy-dispersive X-ray spectroscopy (EDS). Micronuclei test of blood cells, comet assay of liver tissue and histological analysis of liver and kidney tissues were conducted after different treatments to evaluate the toxicity. Fish receiving COOH-SWCNT developed more numbers of micronuclei than COOH-SWCNT-CS treatments. Similarly, more DNA damage was observed in fish injected with nanotubes alone than chitosan hybrid groups. Histological observations revealed severe liver cell damage at higher concentrations of COOH-SWCNT whereas, in COOH-SWCNT-CS, no such damage was observed. However, kidney tissue remained unaffected in all groups. The study suggests that the nanohybrid developed will be safe and useful for delivery of micro or macro biomolecules in fish and higher animals.