Preparation of ZIF-8/PAN composite nanofiber membrane and its application in acetone gas monitoring

Recombinant streptococcal protein G-modified metal-organic framework ZIF-8 for the highly selective purification of immunoglobulin G from human serum

A novel solid phase extractant His-rSPG@ZIF-8 was prepared by covalently coupling recombinant streptococcal protein G (His-rSPG) with ZIF-8. The His-rSPG@ZIF-8 composite was characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Due to the specific binding between the immunoglobulin binding region of His-rSPG and the Fc region of immunoglobulin G (IgG), the His-rSPG@ZIF-8 composite demonstrated exceptional selectivity in adsorbing IgG. In Britton-Robinson buffer (BR buffer) with a salt concentration of 500 mmol L-1 (0.04 mol L-1, pH 8.0), the His-rSPG@ZIF-8 composite exhibited a remarkable adsorption efficiency of 99.8 % for 0.05 mg of the composite on 200 μL of IgG solution (100 μg mL-1). The adsorption behavior of the His-rSPG@ZIF-8 composite aligns with the Langmuir adsorption model, and the theoretical maximum adsorption capacity is 1428.6 mg g-1. The adsorbed IgG molecules were successfully eluted using a SDS solution (0.5 %, m/m), resulting in a recovery rate of 91.2 %. Indeed, the His-rSPG@ZIF-8 composite was successfully utilized for the isolation and purification of IgG from human serum samples. The obtained IgG exhibited high purity, as confirmed by SDS-PAGE analysis. Additionally, LC-MS/MS analysis was employed to identify the human serum proteins following the adsorption and elution process using the His-rSPG@ZIF-8 composite material. The results revealed that the recovered solution contained an impressive content of immunoglobulin, accounting for 62.4 % of the total protein content. Furthermore, this process also led to the significant enrichment of low abundance proteins such as Serpin B4 and Cofilin-1. Consequently, the His-rSPG@ZIF-8 composite holds great promise for applications such as IgG purification and immunoassays. At the same time, it expands the application of metal-organic frameworks in the field of proteomics.

In-situ construction of WS2/ZIF-8 composites with an electron-rich interface for enhancing nitrogen photofixation

Photocatalytic nitrogen reduction reaction (PNRR) is an environmentally friendly synthesis method. It has been regarded as a promising approach for future NH3 preparation, which can reduce the natural fuel consumption and pollution of the Haber Bosch process. Nevertheless, this method exists poor activity for mass production, so it is urgent but challenging to explore highly efficient catalysts. Here, the novel WS2/ZIF-8 composites are reported, DFT and XPS indicate the transfer direction of electrons is from ZIF-8 to WS2, forming an electron-rich interface between WS2 and ZIF-8, thus it endows the more powerful photocatalytic nitrogen reduction ability for 2-WS2/ZIF-8 than monomer material. Meanwhile, 2-WS2/ZIF-8 exhibits admirable photocatalytic nitrogen reduction performance under real and simulated sunlight or in tap water, further attesting its excellent stability and practicability.