Highly biocompatible multi-walled carbon nanotube–chitosan nanoparticle hybrids as protein carriers

Carbon nanotube (CNT)–organic polymer hybrids have important potential applications in the immobilization of therapeutic biomolecules. Recently developed CNT–organic polymer composites require the use of organic solvents for their preparation and have limited polymer functionalization. To address these limitations, multi-walled CNT (MWCNT)–chitosan nanoparticle (CS NP) hybrids have been synthesized in situ by an ionotropic gelation process, which is extremely mild and involves the mixture of two aqueous solutions at room temperature. The MWCNT–CS NP hybrids were characterized by atomic force microscopy and thermogravimetric analysis. Under optimal conditions the CS NP can be tethered to the MWCNT surface in high density and with relatively uniform coverage. The MWCNT–CS NP hybrids show good dispersibility and stability in aqueous solutions. In order to evaluate the potential utilization of the hybrids as protein carries the cytotoxicity to HeLa cells and protein immobilization (of bovine serum albumin (BSA), used here as a model) capacity of the hybrids were investigated in detail. The results demonstrate that the MWCNT–CS NP hybrids are biocompatible at concentrations up to 100 μg mL−1 for 24 h incubation. The MWCNT–CS NP hybrids improve the BSA immobilization efficiency 0.8 times and simultaneously decrease the cellular toxicity by about 50% compared with carboxylated MWCNT.