Enhancement of Binding Affinity of Anti-Hapten Polyclonal IgG Recognizing Mitragynine using Affinity Purification

Antibodies are glycoproteins found in peritoneal fluid, serum, and blood. The antibody-based assay has been used for broad applications such as immunodiagnostic and other biomedical applications. Depending on the intended application, a highly purified polyclonal antibody could be used as an alternative. Purification of antibodies from anti-sera has been proven as one of the methods to enhance the binding affinity of antibodies towards its antigen. We report herein the enhancement of the binding affinity of anti-hapten polyclonal IgG recognizing mitragynine using affinity purification. Serum from the terminal bleed of New Zealand White (NZW) rabbits immunized with mitragynine conjugated with cationized– bovine serum albumin at methyl ester (C22-MG-cBSA), or aromatic ether modification (C9-MG-cBSA) were subjected to HiTrap Protein G affinity purification using fast protein liquid chromatography (FPLC). The elution peak from chromatography fractions was analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. Here, we report the binding of polyclonal antibodies produced from inoculation of either C22-MG-cBSA or C9-MG-cBSA immunogens of which mitragynine-ovalbumin (MG-OVA) was used as coating antigen in the ELISA assay. Non purified anti-sera from C22-MG-cBSA-inoculated rabbits showed higher titer than C9-MG-cBSA at 1/128 000 and 1/32 000 dilutions, respectively. The affinity of purified poly-IgGs from rabbits immunized with C22-MG-cBSA showed a mean Kd value of 7.965 × 10-6 μM, which was lower than those immunized with C9-MG-cBSA at mean Kd of 1.390 × 10-4 μM. In addition, the purified poly- IgGs showed higher binding towards MG-OVA than non-purified anti-sera at comparable protein concentrations. These results indicated that the higher binding affinity of purified polyclonal IgG is due to the reduced competition among polyclonal antibodies with non- IgG proteins that co-existed in the non-purified anti-sera after the affinity purification.

Perfluorocyclohexenyl (PFCH) aromatic ether polymers from perfluorocyclohexene and polycyclic aromatic bisphenols

Semi-fluorinated Perfluorocycloalkenyl (PFCA) aromatic polymers prepared from polycyclic aromatic hydrocarbon (PAH) bisphenols and contain reactive fluoroalkene linkages.

Benzoxazine Containing Fluorinated Aromatic Ether Nitrile Linkage: Preparation, Curing Kinetics and Dielectric Properties

Benzoxazine containing fluorinated aromatic ether nitrile linkage (FAEN-Bz) had been synthesized from 2,6-dichlorobenzonitrile, 4,4’-(hexafluoroisopropylidene)diphenol (bisphenol AF), 3-Aminophenol, formaldehyde, phenol by condensation polymerization and Mannich ring-forming reaction. Structures of the monomer were verified by Proton NMR spectrum (1H-NMR) and Fourier transform infrared spectroscopy (FTIR). Curing behaviors and curing kinetics of designed monomers were investigated and discussed. The activation energy was calculated and possible polymerization mechanisms were also proposed. Then, properties of cured polymers including crosslinking degrees, thermal decomposition, surface wettability and energy, and dielectric properties were studied and discussed. Additionally, programmed integral decomposition temperature (IPDT) was also used to evaluate the thermal stability of final polymers. Results indicated that the incorporation of benzoxazine and nitrile resulted in increased thermal stability and char yields. Moreover, the surface wettability and dielectric properties of poly(FAEN-Bz) can be easily controlled by tuning the curing temperatures and time.

Interaction between Persistent Organic Pollutants and ZnO NPs in Synthetic and Natural Waters

The use of zinc oxide nanoparticles (ZnO NPs) and polybrominated diphenyl ethers (PBDPEs) in different products and applications leads to the likelihood of their co-occurrence in the aquatic system, making it important to study the effect of PBDPEs on the fate and transport of ZnO NPs. In this study, we determine the influence of PBDPEs (BDPE-47 and BDPE-209) on the colloidal stability and physicochemical properties of ZnO NPs in different aqueous matrices. The results indicated the shift in ζ potential of ZnO NP from positive to negative in the presence of both PBDPEs in all tested waters; however, the effect on the NPs surface potential was specific to each water considered. The lower concentration of the PBDPEs (e.g., 0.5 mg/L) significantly reduced the ζ potential and hydrodynamic diameter (HDD) of ZnO NP, even in the presence of high content of dissolved organic matter (DOM) in both freshwater and industrial wastewater. Moreover, both BDPE-47 and BDPE-209 impede the agglomeration of ZnO NP in simple and natural media, even in the presence of monovalent and polyvalent cations. However, the effect of BDPE-47 on the ζ potential, HDD, and agglomeration of ZnO NP was more pronounced than that of BDPE-209 in all tested waters. The results of Fourier transform infrared (FT-IR) and X-ray Photon Spectroscopy (XPS) further confirm the adsorption of PBDPEs onto ZnO NP surface via aromatic ether groups and Br elements. The findings of this study will facilitate a better understanding of the interaction behavior between the ZnO NPs and PBDPEs, which can reduce the exposure risk of aquatic organisms to both pollutants.

Ru/hydroxyapatite as a dual-functional catalyst for efficient transfer hydrogenolytic cleavage of aromatic ether bonds without additional bases

Transfer hydrogenolytic cleavage of aromatic ether bonds could be efficiently carried out by employing Ru/hydroxyapatite as a dual-functional catalyst without additional bases.