Purification of hemoglobin by adsorption on nitrogen-doped flower-like carbon superstructures.

Nitrogen-doped flower-like carbon superstructures (NPC-F) are prepared via carbonizing self-assembled polyimide nanosheets. SEM, TEM, XPS, and N2 sorption methods are adopted to characterize the flower-like structure. NPC-F exhibits adsorption selectivity for hemoglobin (Hb) because the specific pyridinic N groups of NPC-F could coordinate with the sixth vacancy of ferrous ion in hemoglobin. The adsorption behavior fits well with Langmuir model with a maximum adsorption capacity of 360.0 mg g-1 and the adsorbed Hb could be lightly stripped from the NPC-F nanospheres surface by 0.5 wt% CTAB solution. Circular dichroism spectra indicate no obvious conformation changing of Hb during purification process by NPC-F nanospheres. Five cycles of a continuous adsorption/desorption experiment demonstrate the reusability of NPC-F as adsorbent for Hb. The prepared NPC-F superstructures are then employed for the isolation of Hb from human whole blood sample, obtaining high-purity Hb as demonstrated by sodium dodecyl sulfate polyacrylamide gel electrophoresis assays. Graphical abstractNitrogen-doped flower-like carbon superstructure (NPC-F) is used to isolate target protein. NPC-F exhibits highly selective capture capacity towards hemoglobin because the specific pyridinic N groups of NPC-F could coordinate with the sixth vacant coordinating position of Fe2+ in hemoglobin.

Zn-based metal organic framework-covalent organic framework composites for trace lead extraction and fluorescence detection of TNP.

A novel dual functional composite (MOFL-TpBD) was prepared through solvothermal methods, with excellent Pb2+ ions separation and stable 2,4,6-Trinitrophenol (TNP) fluorescence detection performance. MOFL-TpBD was characterized by FTIR, XRD, XPS, SEM and TGA et al. The prepared material was used to extract Pb2+ ions, with an adsorption capacity of 21.74 mg g-1 calculated by Langmuir isotherm model. The limit of detection was 0.32 µg L-1, along with a linear range from 0.7 to 12 µg L-1 and a precision of 5.4% (1 µg L-1, n = 9), respectively, where MOFL-TpBD was adopted as adsorbent for Pb2+ ions preconcentration. The practical samples and reference water sample were measured by the provided method, with the satisfactory recoveries (91-110%) and reliable analytical results. MOFL-TpBD was capable of fluorescent sensing of TNP, with a linear range from 0.01 to 1 mM and a limit of detection of 3.52 µM, respectively, and a precision of 3.29% was obtained (0.2 mM, n = 11). Meanwhile, the recoveries ranged from 91% to 108% in analysis of TNP for the practical samples. The designed material provided a potential candidate material for the detection of heavy metal ions and explosives in environmental water samples.

Boron-Modified Defect-Rich Molybdenum Disulfide Nanosheets: Reducing Nonspecific Adsorption and Promoting a High Capacity for Isolation of Immunoglobulin G.

A new type of boric acid derivative-modified molybdenum disulfide nanosheet was prepared by amination and sulfur chemical grafting, where lipoic acid, lysine, and 5-carboxybenzoboroxole were used as reactants. The two-dimensional composite, abbreviated as MoS2-Lys-CBX, is an ultrathin nanosheet with a minimum unit of single or few layers. Compared with the original molybdenum disulfide, the nonspecific adhesion of interfering proteins on the surface was reduced, and the adsorption capacity of glycoproteins was enhanced, which was 1682.2 mg g-1 represented by IgG. The adsorbed IgG can be easily eluted with 0.3 wt % CTAB with an elution efficiency of 94.1%. Circular dichroism spectra indicate no obvious conformation change of IgG during the purification process by the MoS2-Lys-CBX nanosheets. The as-prepared MoS2-Lys-CBX nanosheets were then employed for the isolation of IgG from human serum sample, obtaining high-purity light and heavy chains of IgG, as demonstrated by SDS-PAGE assays.

DMSA-Functionalized Mesoporous Alumina with a High Capacity for Selective Isolation of Immunoglobulin G.

A novel dimercaptosuccinic acid-functionalized mesoporous alumina (DMSA-MA) is synthesized by the dicarboxylic acid groups of dimercaptosuccinic acid molecules coordinating to the Al3+ ions located in the mesostructure. The as-prepared DMSA-MA composites possess a large surface area of 91.17 m2/g as well as a uniform pore size and a high pore volume of 17.22 nm and 0.23 cm3/g, respectively. DMSA coating of mesostructures significantly enhanced their selectivity for glycoprotein adsorption through a powerful hydrophilic binding force, and the maximum adsorption capacity of immunoglobulin G (IgG) can reach 2298.6 mg g-1. The captured IgG could be lightly stripped from the DMSA-MA composites with an elution rate of 98.3% by using 0.5 wt % CTAB solution as the elution reagent. DMSA-MA is further employed as a sorbent for the enrichment of IgG heavy chain and light chain from human serum sample. SDS-PAGE assay results showed the obtained IgG with high purity compared to that of the standard solution of IgG.