Adsorption and separation of proteins by collagen fiber adsorbent

Adsorption of BSA Protein in Aqueous Medium Using Vegetable Tannin Resin from Acacia mearnsii (Mimosa) and Modified Lignocellulosic Fibers from the Bark of Eucalyptus citriodora

Proteins are abundant biomolecules found in human cells, as well as pathogenic bacteria and viruses. Some of them become pollutants when released into water. Adsorption is an advantageous method for separating proteins in aqueous media since proteins are already immobilized on solid surfaces. Adsorbents with surfaces rich in tannins are efficient due to their affinity for strong interactions with the various amino acids that make up proteins. This work aimed to develop an adsorbent for protein adsorption in aqueous medium using lignocellulosic materials modified from eucalyptus bark and vegetable tannins. A more efficient resin was prepared containing 10% eucalyptus bark fibers and 90% tannin mimosa by condensation with formaldehyde, and it was characterized by UV-Vis, FTIR-ATR spectroscopy and determinations of degree of swelling, bulk and bulk density and specific mass. For UV-Vis spectroscopy the percentage of condensed and hydrolysable tannins in the extracts of fibers of the dry husks of Eucalyptus Citriodora was estimated and it was also determined your soluble solids. The study of bovine serum albumin (BSA) adsorption was carried out in batch with quantification by UV-Vis spectroscopy. The most efficient prepared resin obtained 71.6 ± 2.78% removal in a solution of 260 mg L-1 of BSA working in a better pH range of the aqueous solution of BSA in its isoelectric point, ~ 5, 32 ± 0.02, under these conditions, the synthesized resin can reach a maximum BSA adsorption capacity of ~ 26.7 ± 0.29 mg g-1 in 7 min. The new synthesized resin presents good prospects for adsorption of proteins or species that in their structure have higher percentages of amino functional groups or amino acids with aliphatic, acidic and/or basic hydrophilic characteristics.

Graphical Abstract

Collagen processing with mesoscale aggregates as templates and building blocks

Collagen presents a well-organized hierarchical multilevel structure. Microfibers, fibers, and fiber bundles are the aggregates of natural collagen; which achieve an ideal balance of mechanical strength and toughness at the mesoscopic scale for biological tissue. These mesostructured aggregates of collagen isolated from biological tissues retain these inherent organizational features to enable their use as building blocks for constructing new collagen materials with ideal mechanical performance, thermal and dimensional stability. This strategy is distinct from the more common bottom-up or molecular-level design and assembly approach to generating collagen materials. The present review introduces the hierarchical structure of biological collagen with a focus on mesostructural features. Isolation strategies for these collagen aggregates (CAs) are summarized. Recent progress in the use of these mesostructural components for the construction of new collagen materials with emerging applications is reviewed, including in catalysis, environmental applications, biomedicine, food packaging, electrical energy storage, and flexible sensors. Finally, challenges and prospects are assessed for controllable production of CAs as well as material designs.

Collagen Fiber-Based Advanced Separation Materials: Recent Developments and Future Perspectives

Separation plays a critical role in a broad range of industrial applications. Developing advanced separation materials is of great significance for the future development of separation technology. Collagen fibers (CFs), the typical structural proteins, exhibit unique structural hierarchy, amphiphilic wettability, and versatile chemical reactivity. These distinctive properties provide infinite possibilities for the rational design of advanced separation materials. During the past 2 decades, many progressive achievements in the development of CFs-derived advanced separation materials have been witnessed already. Herein, the CFs-based separation materials are focused on and the recent progresses in this topic are reviewed. CFs widely existing in animal skins display unique hierarchically fibrous structure, amphiphilicity-enabled surface wetting behaviors, multi-functionality guaranteed covalent/non-covalent reaction versatility. These outstanding merits of CFs bring great opportunities for realizing rational design of a variety of advanced separation materials that were capable of achieving high-performance separations to diverse specific targets, including oily pollutants, natural products, metal ions, anionic contaminants and proteins, etc. Besides, the important issues for the further development of CFs-based advanced separation materials are also discussed.

Bio-templated synthesis of porous silica nano adsorbents to wastewater treatment inspired by a circular economy

Water is an indispensable substance in human life activities. However, due to industrial discharge problems, water resources are polluted, so there is an urgent need for material and technology for wastewater treatment. This paper presents an innovative synthesis of porous silica microspheres (PSM) from a biomass template material (fish skin collagen) to treat protein from wastewater. The collagen from the biomass template was rich in amino, carboxyl, and hydroxyl groups that effectively controlled the hydrolysis rate of tetraethyl orthosilicate (TEOS) and promoted the synthesis of structured PSM. X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), nitrogen sorption isotherms measurements, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to characterize the chemical composition, crystalline structure, and pore architecture of the synthesized PSM. The characterization results confirmed that the PSM were spherical with the microporous and mesoporous structure in shape and approximately 400 nm in size. Moreover, the pore size could be tuned by addition of mesitylene (TMB). The large number of silicon hydroxyl groups on the PSM surface effectively bound proteins in wastewater and greatly improved the overall absorption rate. The PSM adsorption capacity for lysozyme (LZ) was 49.5 mg/g, and the adsorption behavior was well described by a pseudo-second-order kinetic model and the Langmuir model. Most importantly, the PSM effectively removed protein from actual industrial wastewater, thereby realizing a high value-added utilization of wastewater pollutants.

In-situ preparation of silver salts/collagen fiber hybrid composites and their photocatalytic and antibacterial activities

To promote the utilization of collagen fiber, silver salts/collagen fiber hybrid composites with photocatalytic and antibacterial activities were successfully prepared in this study via the in-situ organic-inorganic process. The surface morphology, chemical composition and structure were discussed. Scanning electron microscopy (SEM) observation showed that the silver salts/collagen fiber hybrid composites were successfully prepared with silver salt particles (300-500 nm) distributing evenly on the surface of collagen fiber. X-ray diffraction (XRD) patterns and Fourier transform infrared spectroscopy (FTIR) analysis provided strong evidence for the successful coating of silver salts on the surface of collagen fiber and the hybrid mechanism was subsequently discussed. The photocatalytic activity was evaluated by degrading methyl orange (MO) under ultraviolet (UV) light and visible light, respectively. The results indicated that AgCl/Collagen Fiber showed the most efficient photocatalytic activity under UV and visible light irradiation. Furthermore, the introduction of Ag⁺ endowed the photocatalysts with antibacterial performance, which was investigated by measuring the width of the bacteriostatic belts. The results indicated the antibacterial activity of the composites, proving that the photocatalysts were durable and reusable.

Synthesis of human hair fiber-impregnated chitosan beads functionalized with citric acid for the adsorption of lysozyme

Herein, a novel CA-CS/HHF composite was firstly constructed by impregnating human hair fiber into a CS matrix and then functionalized with citric acid.

Scalable Fabrication of Electrospun Nanofibrous Membranes Functionalized with Citric Acid for High-Performance Protein Adsorption

Fabricating protein adsorbents with high adsorption capacity and appreciable throughput is extremely important and highly desired for the separation and purification of protein products in the biomedical and pharmaceutical industries, yet still remains a great challenge. Herein, we demonstrate the synthesis of a novel protein adsorbent by in situ functionalizing eletrospun ethylene-vinyl alcohol (EVOH) nanofibrous membranes (NFM) with critic acid (CCA). Taking advantage of the merits of large specific surface area, highly tortuous open-porous structure, abundant active carboxyl groups introduced by CCA, superior chemical stability, and robust mechanical strength, the obtained CCA-grafted EVOH NFM (EVOH-CCA NFM) present an excellent integrated protein (take lysozyme as the model protein) adsorption performance with a high capacity of 284 mg g(-1), short equilibrium time of 6 h, ease of elution, and good reusability. Meanwhile, the adsorption performance of EVOH-CCA NFM can be optimized by regulating buffer pH, ionic strength, and initial concentration of protein solutions. More importantly, a dynamic binding efficiency of 250 mg g(-1) can be achieved driven solely by the gravity of protein solution, which matches well with the demands of the high yield and energy conservation in the actual protein purification process. Furthermore, the resultant EVOH-CCA NFM also possess unique selectivity for positively charged proteins which was confirmed by the method of sodium dodecyl sulfate polyacrylamide gel electrophoresis. Significantly, the successful synthesis of such intriguing and economic EVOH-CCA NFM may provide a promising candidate for the next generation of protein adsorbents for rapid, massive, and cost-effective separation and purification of proteins.

Quaternized polysulfone and graphene oxide nanosheet derived low fouling novel positively charged hybrid ultrafiltration membranes for protein separation

Low fouling positively charged hybrid UF membranes with adjustable charge density fabricated from a blend of PSf/QPSf and GO nanosheets by solution casting and NIPS method. Cross-section SEM image and observed lysozyme transport values at varied pH.

Cystatin C: Its role in pathogenesis of OSMF

Oral Submucous Fibrosis (OSF) is a chronic disorder characterized by fibrosis of the mucosa lining the upper digestive tract involving the oral cavity, oro- and hypopharynx and the upper third of the oesophagus. The alkaloids from areca nut are the most important chemical constituents biologically, in producing this lesion. These chemicals appear to interfere with the molecular processes of deposition and/or degradation of extracellular matrix molecules such as collagen. Increased collagen synthesis or reduced collagen degradation have been considered as a possible mechanism in the development of the disease. Increased and continuous deposition of extracellular matrix may also take place as a result of disruption of the equilibrium between matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMP). Arecoline a product of areca nut was found to elevate Cystatin C mRNA (CST3) and protein expression in a dose-dependent manner. Cystatin C expression was significantly higher in OSF specimens and expressed mainly by fibroblasts, endothelial cells, and inflammatory cells. Cross-links between the molecules are essential for the tensile strength of collagen fibres. These areas are resistant to attack by collagenases but can be attacked by a number of other serine and cysteine proteinases. CST3 encoding a cysteine proteinase inhibitor might contribute to the stabilization of collagen fibrils in OSMF. Treatment directed against Cystatin C may serve as a novel treatment for submucous fibrosis and also in preventing its transformation into malignancy.