Probing the behavior and kinetic studies of amphiphilic acrylate copolymers with bovine serum albumin

This article presents that acrylate copolymers are the potential candidate against the adsorption of bovine serum albumin (BSA). A series of copolymers poly(methyl methacrylate) (pMMA), poly(3-sulfopropyl methacrylate-co-methyl methacrylate) p(SPMA-co-MMA), and poly(dimethylaminoethyl methacrylate-co-methyl methacrylate) p(DMAEMA-co-MMA) were synthesized via free radical polymerization. These amphiphilic copolymers are thermally stable with a glass transition temperature (Tg) 50-120 °C and observed the impact of surface charge on amphiphilic copolymers to control interactions with the bovine serum albumin (BSA). These copolymers pMD1 and pMS1 have surface charges, - 56.6 and - 72.6 mV at pH 7.4 in PBS buffer solution that controls the adsorption capacity of bovine serum albumin (BSA) on polymers surface. Atomic force microscopy (AFM) analysis showed minimum roughness of 0.324 nm and 0.474 nm for pMS1 and pMD1. Kinetic studies for BSA adsorption on these amphiphilic copolymers showed the best fitting of the pseudo-first-order model that showed physisorption and attained at 25 °C and pH 7.4 within 24 h.

Application of Ion Exchange and Adsorption Techniques for Separation of Whey Proteins from Bovine Milk

Background:

The world production of whey was estimated to be more than 200 million tons per year. Although whey is an important source of proteins with high nutritional value and biotechnological importance, it is still considered as a by-product of the dairy industry with low economic value due to low industrial exploitation. There are several challenges in the separation of whey proteins: low concentration, the complexity of the material and similar properties (pI, molecular mass) of some proteins.

Methods:

A narrative review of all the relevant papers on the present methodologies based on ion-exchange and adsorption principles for isolation of whey proteins, known to the authors, was conducted.

Results:

Traditional ion-exchange techniques are widely used for the separation and purification of the bovine whey proteins. These methodologies, based on the anion or cation chromatographic procedures, as well as combination of aforementioned techniques are still preferential methods for the isolation of the whey proteins on the laboratory scale. However, more recent research on ion exchange membranes for this purpose has been introduced, with promising potential to be applied on the pilot industrial scale. Newly developed methodologies based either on the ion-exchange separation (for example: simulated moving bed chromatography, expanded bed adsorption, magnetic ion exchangers, etc.) or adsorption (for example: adsorption on hydroxyapatite or activated carbon, or molecular imprinting) are promising approaches for scaling up of the whey proteins’ purification processes.

Conclusion:

Many procedures based on ion exchange are successfully implemented for separation and purification of whey proteins, providing protein preparations of moderate-to-high yield and satisfactory purity. However, the authors anticipate further development of adsorption-based methodologies for separation of whey proteins by targeting the differences in proteins’ structures rather than targeting the differences in molecular masses and pI. The complex composite multilayered matrices, including also inorganic components, are promising materials for simultaneous exploiting of the differences in the masses, pI and structures of whey proteins for the separation.

Development of surface imprinted heterogeneous nitrogen-doped magnetic carbon nanotubes as promising materials for protein separation and purification

To promote the development of molecular imprinting technique in the separation and analysis of protein, novel bovine serum albumin (BSA) surface imprinted nitrogen-doped magnetic carbon nanotubes (N-MCNTs@MIPs) are developed by this paper. The imprinted materials are prepared by depositing polydopamine (PDA) on the surface of nitrogen-doped magnetic carbon nanotubes (N-MCNTs). N-MCNTs prepared by high temperature pyrolysis and chemical vapor deposition exhibit high specific surface area, positive hydrophilicity, abundant nitrogen functional groups and excellent magnetic properties. These characteristics are conducive to the increase of effective binding sites, the smooth development of the protein imprinting process in the aqueous phase, the improvement of the binding capacity and the simplification of the separation process. The amount of BSA adsorbing on the N-MCNTs@MIPs can reach 150.86 mg/g within 90 min. The imprinting factor (IF) is 1.43. The results of competitive adsorption and separation of fetal bovine serum showed that N-MCNTs@MIPs can specifically recognize BSA. The excellent reusability and separation ability for real sample prove that N-MCNTs@MIPs have the potential to be applied to the separation and purification of proteins in complex biological samples.

Coupling and Regulation of Porous Carriers Using Plasma and Amination to Improve the Catalytic Performance of Glucose Oxidase and Catalase

Multiple enzyme systems are being increasingly used for their high-efficiency and co-immobilization is a key technology to lower the cost and improve the stability of enzymes. In this study, poly glycidyl methacrylate (PGMA) spheres were synthesized using suspension polymerization, and were used as a support to co-immobilize glucose oxidase (GOx) and catalase (CAT). Surface modification was carried out via a combination of plasma and amination to promote the properties of the catalyzer. The co-immobilized enzymes showed a more extensive range of optimum pH and temperature from 5.5 to 7.5 and 25 to 40°C, respectively, compared to free enzymes. Furthermore, the maximum activity and protein adsorption quantity of the co-immobilized enzymes reached 25.98 U/g and 6.07 mg/g, respectively. The enzymatic activity of the co-immobilized enzymes was maintained at ~70% after storage for 5 days and at 82% after three consecutive cycles, indicating that the immobilized material could be applied industrially.

Ni2+-BSA Directional Coordination-Assisted Magnetic Molecularly Imprinted Microspheres with Enhanced Specific Rebinding to Target Proteins

Protein imprinting technology is of interest in drug delivery, biosensing, solid-phase extraction, and so forth. However, the efficient recognition and separation of proteins have remained challenging to date. Toward this, under the assistance of Ni²⁺-bovine serum albumin (BSA) directional coordination strategy, magnetic BSA-imprinted materials had been synthesized via dopamine self-polymerization on hollow Fe₃O₄@mSiO₂ microspheres (mSiO₂ referred as mesoporous silica). The well-defined imprinted microspheres possessed more satisfactory adsorption capacity (266.99 mg/g), enhanced imprinting factor (5.45), and fast adsorption saturation kinetics (40 min) for BSA, superior to many previous reports. Benefiting from the coordinate interaction between Ni²⁺ and BSA, these fabricated microspheres exhibited excellent specificity not only in individual and competitive protein rebinding samples but also in bovine serum. Combined with the directional coordination method, the magnetic-imprinted composite materials to selectively capture target proteins could provide promising potential in applications.