title: L-histidine functionalized multi-walled carbon nanotubes for on-line affinity separation and purification of immunoglobulin G in serum.
abstract: In this work, the multi-walled carbon nanotubes were covalently functionalized with L-histidine (His-MWNTs) as online pseudospecific affinity adsorbent for immunoglobulin G (IgG) separation and purification with a simple surface modification method, using 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimde (NHS). The affinity of the His-MWNTs toward IgG was investigated in a microcolumn incorporated into a sequential injection system, which also involves an UV spectrometer with a flow cell for online real-time detection. The incorporation of histidine as affinity groups noticeably increased the selectivity and binding capacity of MWNTs for IgG and the His-MWNTs exhibited high retention and recovery rate of nearly 100% under optimized conditions. This separation and enrichment process made it possible to determine a lower concentration range of IgG in serum from 1.0-33 μg/mL with a detection limit of 0.3 μg/mL with a sampling volume of 4.0 mL. The static and dynamic adsorption capacities obtained were 267 mg of IgG/g His-MWNTs and 35 mg/g in aqueous solution, respectively, which are among the highest reported results in literatures employing affinity separation methods. Desorption of IgG from His-MWNTs could be accomplished by lowering the pH to 1.5 with glycine-HCl buffer. The practical application of His-MWNTs for separation of IgG in serum was evaluated with sodium dodecyl sulfate-polyacrylamide gel electrophoresis which confirmed that the purity of recovered IgG from human serum was over 85% and better than a commercial product.
authors.affiliation: School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275, China. duzh@mail.sysu.edu.cn
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Du
authors.forename: Suling
authors.initials: S
authors.lastname: Zhang
authors.forename: Chanyuan
authors.initials: C
authors.lastname: Zhou
authors.forename: Miao
authors.initials: M
authors.lastname: Liu
authors.forename: Gongke
authors.initials: G
authors.lastname: Li
mesh_terms: D000818:Animals; D002417:Cattle; D005591:Chemical Fractionation / Q000379:methods*; D006639:Histidine / Q000737:chemistry*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification*; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009862:Online Systems; D015203:Reproducibility of Results
chemical_list: D007074:Immunoglobulin G; D008024:Ligands; D037742:Nanotubes, Carbon; D006639:Histidine