Functionalization Of Multiwalled Carbon Nanotubes With Poly (Aspartic Acid) Regulated With Amino Acids For Lysozyme Adsorption

A large surface area and tunable length, as well as unique physicalproperties, make carbon nanotubes (CNTs) welcome candidates in medicine.But smooth surfaces without any hanging bonds make pristine CNTschemically inert and incompatible with nearly all organic and inorganicsolvents, and this has formed a major drawback for CNTs' applications innanomedicine. So we need to functionalize CNTs.In this study, we developed a new type of amphiphilic polymer namedPASP C16through grafting poly (aspartic acid) with hexadecylamine. Wewrapped PASP C16on the surface of CNTs through the hydrophobic force tobreak the π π force which made CNTs assemble, so we can increase thesolubility and dispersion of CNTs in aqueous solution. In order to improvedispersion, we used different concentration of L serine, L leucine, L arginine,L lysine solvent to adjust the effect of the functionalization. We chose theoptimal concentration of amino acid solution for the best functional effectthrough the UV vis spectrum. The CNTs functionlized with PASP C16through physical adsorption in the optimal amino acid solution wasinvestigated by analyzing X ray diffraction (XRD) patterns, Roman spectra,Fourier transform infrared spectroscopy (FTIR), X ray photoelectronspectroscopy (XPS), Thermal gravimetric analysis (TGA) and high resolutiontransmission electron microscopy (HRTEM).The adsorption of lysozyme (LYZ) onto functionalized CNTs has beenstudied and characterized with vis spectrophotometer and fluorescence spectrum. The results showed that the enzyme activity and conformation ofadsorbed LYZ has been well preserved. It has been demonstrated that, thefunctionalized CNTs with amphiphilic PASP C16on their exterior surfacehave a good dispersibility in water and are biocompatible, may have apotential application of drug delivery.