Coating of nanoparticles on cryogel surface and subsequent double-modification for enhanced ion-exchange capacity of protein

Fabrication of a Heptapeptide-Modified Poly(glycidyl Methac-Rylate) Nanosphere for Oriented Antibody Immobilization and Immunoassay

Oriented antibody immobilization has been widely employed in immunoassays and immunodiagnoses due to its efficacy in identifying target antigens. Herein, a heptapeptide ligand, HWRGWVC (HC7), was coupled to poly(glycidyl methacrylate) (PGMA) nanospheres (PGMA-HC7). The antibody immobilization behavior and antigen recognition performance were investigated and compared with those on PGMA nanospheres by nonspecific adsorption and covalent coupling via carbodiimide chemistry. The antibodies tested included bovine, rabbit, and human immunoglobulin G (IgG), while the antigens included horseradish peroxidase (HRP) and β-2-Microglobulin (β2-MG). The nanospheres were characterized using zeta potential and particle size analyzers, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and reversed-phase chromatography, proving each synthesis step was succeeded. Isothermal titration calorimetry assay demonstrated the strong affinity interaction between IgG and PGMA-HC7. Notably, PGMA-HC7 achieved rapid and extremely high IgG adsorption capacity (~3 mg/mg) within 5 min via a specific recognition via HC7 without nonspecific interactions. Moreover, the activities of immobilized anti-HRP and anti-β2-MG antibodies obtained via affinity binding were 1.5-fold and 2-fold higher than those of their covalent coupling counterparts. Further, the oriented-immobilized anti-β2-MG antibody on PGMA-HC7 exhibited excellent performance in antigen recognition with a linear detection range of 0-5.3 μg/mL, proving its great potential in immunoassay applications.

Facial on-line enrichment of glycoproteins by capillary electrophoresis with boronate-functionalized poly(glycidyl methacrylate) microparticles coated column

A facial and rapid method for glycoproteins enrichment by capillary electrophoresis was developed. The 3-aminophenylboronic acid-functionalized poly(glycidyl methacrylate) microparticles (PGMA@APBA) were attached to the capillary inlet (length of ∼1.5 cm) by electrostatic self-assemble action to prepare a partially coated capillary column. The process is simple and reversible, allowing for easy renewal of the PGMA@APBA coating when its enrichment efficiency decreases. By utilizing the coated column, glycoproteins can be enriched within 2 min. The column exhibits a specific enrichment for glycoproteins and can be consecutively used for approximately 60 runs. The relative standard deviations (RSDs) of peak area of run-to-run (n = 5) and batch-to-batch (n = 3) were 1.5 % and 1.0%, respectively. The method was successfully applied to enrich glycoproteins from 1 × 1012-fold diluted real egg white sample, indicating its practical applicability.

Preparation of Hydrophobic Cryogel Containing Hydroxyoxime Extractant and Its Extraction Properties of Cu(Ⅱ)

Hydrophobic cryogels with monolithic supermacropores based on poly-trimethylolpropane trimethacrylate (pTrim) containing 1-(2-Hydroxyl-5-nonyphenyl)ethanone oxime (LIX84-I) were successfully prepared by a cryo-polymerization technique using organic solvents with freezing points between room temperature and around 0 °C as solvents. The prepared cryogels were characterized in terms of macroscopic shape and porous structure. The cryogels had a monolithic supermacroporous structure and high contents of LIX84-I depending on the added amount of the extractant to the monomer solution. The amount of LIX84-I impregnated in the cryogel had a linear relationship with the added amount of LIX84-I in the monomer solution for cryo-polymerization. Cu(II) in the aqueous solution was immediately adsorbed into the cryogel containing LIX84-I.

Lectin Purification through Affinity Chromatography Exploiting Macroporous Monolithic Adsorbents

Growing medical, engineering, biochemical, and biological interest has led to a steady pace of research and development into polymeric monolithic structures with densely interconnected pores for purifying bio compounds. Cryogels, which are generated by freezing a reactive polymerization mixture, are highlighted due to their versatility and low relative cost as macroporous, polymeric, monolithic adsorbents. The conversion of cryogels into affinity adsorbents is one possible alternative to their optimal application. Some of the most often utilized supports for immobilizing particular ligands are monolithic columns manufactured with epoxy radicals on their surfaces. The purification of biomolecules with a high degree of specificity, such as lectins and glycoproteins with an affinity for glycosylated groups, has garnered interest in the use of fixed non-traditional beds functionalized with ligands of particular interest. The interaction is both robust enough to permit the adsorption of glycoproteins and reversible enough to permit the dissociation of molecules in response to changes in the solution’s pH. When compared to other protein A-based approaches, this one has been shown to be more advantageous than its counterparts in terms of specificity, ease of use, and cost-effectiveness. Information on polymeric, macroporous, monolithic adsorbents used in the affinity chromatographic purification of lectins has been published and explored.

Amino acid-based hydrophobic affinity cryogel for protein purification from ora-pro-nobis (Pereskia aculeata Miller) leaves

The surfaces of the polyacrylamide cryogels were coated with L-tryptophan (cryogel-Trp) or L-phenylalanine (cryogel-Phe) to enhance crude leaf extract-derived ora-pro-nobis (OPN) protein binding via pseudo-specific hydrophobic interactions. Cryogels functionalized with amino acids were prepared and characterized through morphological, hydrodynamic, and thermal analyses. The adsorption capacities of cryogel-Phe and cryogel-Trp were evaluated in terms of type (sodium sulfate or sodium phosphate) and concentration (0.02 or 0.10 mol∙L^-1) of saline solution, pH (4.0, 5.5, or 7.0), and NaCl concentration (0.0 or 0.5 mol∙L^-1). The cryogel-Phe presented a higher adsorptive capacity, achieving its maximum value (q = 92.53 mg∙g^-1) when the crude OPN crude leaf extract was diluted in sodium sulfate 0.02 mol∙L^-1 + NaCl 0.50 mol∙L^-1, at pH = 7.0. The dilution rate significantly (p < 0.05) affected the recovered protein amount after the adsorption and elution processes, reaching 94.45% when the feedstock solution was prepared with a crude extract 5 times. The zeta potential for the eluted OPN proteins was 5.76 mV (pH = 3.23) for both dilution rates. The secondary structure composition mainly included β-sheets (46.50%) and α-helices (13.93%). The cryogel-Phe exhibited interconnected pores ranging 20-300 μm in size, with a Young modulus of 1.51 MPa, and thermal degradation started at 230 °C. These results indicate that the cryogel-Phe exhibited satisfactory properties as promising chromatography support for use in high-throughput purification of crude leaf extract-derived OPN proteins.

Biochemical engineering in China

Chinese biochemical engineering is committed to supporting the chemical and food industries, to advance science and technology frontiers, and to meet major demands of Chinese society and national economic development. This paper reviews the development of biochemical engineering, strategic deployment of these technologies by the government, industrial demand, research progress, and breakthroughs in key technologies in China. Furthermore, the outlook for future developments in biochemical engineering in China is also discussed.

3D cryogel composites as adsorbent for isolation of protein and small molecules

A green and promising sample pretreatment method was successfully established, which efficiently isolated proteins and small molecules in human serum. This method was achieved based on the multifunctional polymer, cryogel, as a solid phase extraction (SPE) monolith easily equipped in a syringe. The cryogel (pDC/GO-DE) was composed of diallyldimethyl ammonium chloride (DC) and 2-hydroxyethyl methacrylate (HE), which was further modified with graphene oxide (GO) and N-diethylethanamine hydrobromide (DE). Various proteins, including bovine serum albumin (BSA), lysozyme (Lys), γ-globulins, immunoglobulin G (IgG), transferrin, small molecules (ribavirin, adenosine, ofloxacin, estriol, rutin, amoxicillin, ibuprofen, 1-methyl-3-phenyl-propylamine, and benzylamine) and their mixtures were successively studied as model analytes to evaluate the new material and demonstrate the isolation mechanism, which was mainly dependent on mixed-mode ion-exchange and the hybrid hydrophobicity-hydrophilicity property of pDC/GO-DE cryogel. Moreover, the three-dimensional macroporous structure contributed to the underlying size-selective isolation. When 10 times diluted human serum was used as the sample, more than 95% of proteins were adsorbed within 10 min under physiological conditions, and the interference matrix in serum was also efficiently reduced. After recycling three times, the extraction ratio of proteins in human serum was still higher than 90%. When four small molecules (camptothecin, ribavirin, 1-methyl-3-phenylpropylamine and ofloxacin) were added to blank human serum, their recoveries were within 65.6-81.8%, and were comparable to those obtained by protein precipitation method (63.7-83.2%).

Grafting zwitterionic polymer onto cryogel surface enhances protein retention in steric exclusion chromatography on cryogel monolith

Cryogel monoliths with interconnected macropores (10-100μm) and hydrophilic surfaces can be employed as chromatography media for protein retention in steric exclusion chromatography (SXC). SXC is based on the principle that the exclusion of polyethylene glycol (PEG) on both a hydrophilic chromatography surface and a protein favors their association, leading to the protein retention on the chromatography surface. Elution of the retained protein can be achieved by reducing PEG concentration. In this work, the surface of polyacrylamide-based cryogel monolith was modified by grafting zwitterionic poly(carboxybetaine methacrylate) (pCBMA), leading the increase in the surface hydrophilicity. Observation by scanning electron microscopy revealed the presence of the grafted pCBMA chain clusters on the cryogel surface, but pCBMA grafting did not result in the changes of the physical properties of the monolith column, and the columns maintained good recyclability in SXC. The effect of the surface grafting on the SXC behavior of γ-globulin was investigated in a wide flow rate range (0.6-12cm/min). It was found that the dynamic retention capacity increased 1.4-1.8 times by the zwitterionic polymer grafting in the flow rate range of 1.5-12cm/min. The mechanism of enhanced protein retention on the zwitterionic polymer-grafted surface was proposed. The research proved that zwitterionic polymer modification was promising for the development of new materials for SXC applications.