Functionalization of Multi‐Walled Carbon Nanotubes and their Application for Selective Isolation of Acidic Proteins

Abstract

A micro-column packed with PDDA-wrapped MWNTs in sequential injection system facilitates selective sorption of acidic protein species. Proteins adsorbed onto the PDDA-MWNT composites are afterwards collected by elution with a citrate buffer as stripping reagent. With a sample loading volume of 2.0 mL and an eluent volume of 200 microL, a retention efficiency of 100% and a recovery of 90% are achieved for BSA in the range 6-120 microg, resulting in an enrichment factor of 14. A sampling frequency of 15 h(-1) is achieved, along with a precision of 4.5% at 25 microg x mL(-1) BSA. The practical applicability of this system is demonstrated by processing human whole blood for successive isolation of acidic proteins.

Functionalization of MWNTs with Hyperbranched PEI for Highly Selective Isolation of BSA

“…The flow rate not only has a significant effect on the adsorption efficiency, but it also determines the lifetime of the microcolumn. [9] In the present system, a microcolumn with a packing length of 10 mm was used for protein adsorption. The effect of sample loading flow rate was investigated within the range 10-50 mL Á s À1 in the presence of 0.002 mol Á L À1 phosphate buffer (pH ¼ 6).…”

“…A dynamic equilibrium was thus established between the adsorption and desorption of BSA onto the BPEI-MWNT surface. The amount of BSA adsorbed onto the column surface, m protein , could be calculated according to Equation (1) and (2): [9] m protein ¼ vc p t e À t 0 ð ÞÀv…”

“…[8] The functionalization of CNTs with soluble polymers gives rise to hydrophilicity, allowing for their use in biological applications and the ability to purify proteins. [9] The noncovalent wrapping of positively charged hydrophilic linear polymer entails selective adsorption of acidic protein species via electrostatic interactions. However, the adsorbed proteins tend to generate lateral repulsion because they are closely contacted in the adsorbed layer; therefore, charged proteins generally tend to adsorb apart from each other.…”

Chromatography of carbon nanotubes separated albumin from other serum proteins: a method for direct analysis of their interactions

“…Surface modification of MWCNT was done via nitric acid treatment, which was a strong oxidant, to induce a negative charge on the surface of MWCNT 10) . In another study 11) , Du et al also demonstrated that PDDA [poly(diallyl dimethyl ammonium chloride)]-modified MWCNT could trap acidic proteins such as bovine serum albumin.…”

Novel polydopamine imprinting layers coated magnetic carbon nanotubes for specific separation of lysozyme from egg white

“…Carbon nanotubes (CNTs), employed as supporting matrix to deal with protein adsorption or isolation, have gained much attention, especially in the field of surface imprinting [14][15][16][17][18]. Yuan et al utilized multiwall CNTs as carrier and ionic liquid as functional monomer to prepare Lyz-imprinted polymers for separating Lyz from egg white [19].…”