Fabrication of rigid and macroporous agarose microspheres by pre-cross-linking and surfactant micelles swelling method

Effect of low degree succinylation on properties of enzyme-induced casein hydrogel

This study examines the impact of succinic anhydride (SA) modification (0-9 %) on the gel properties of casein. Upon succinylation, the surface hydrophobicity (H0) of casein initially increased before decreasing, achieving its peak at a degree of succinylation of 5.22 ± 0.16 %. The α-helix content rose to 14.13 ± 2.60 %, and the -OH peak shifted towards lower wavenumbers, suggesting enhanced hydrogen bonding within intra/intermolecular structures. The storage modulus in the rheological test escalated from 2160.11 Pa to 5047.60 Pa, and SEM analysis revealed that the optimally succinylated casein gel formed a denser and more stable gel network structure. Moreover, succinylated casein hydrogels demonstrated superior texture properties, swelling ability, and thermal stability. Molecular dynamics simulation (MD) results suggest that SA preferentially binds to LYS27 and LYS28 of β-casein via hydrogen bonds and amide bonds, respectively. The interaction between modified proteins is primarily governed by hydrogen bonds, aligning with FT-IR findings. PCA analysis identified a positive correlation between the ordered structure and gel performance. This research offers theoretical insights and reference data for modulating casein hydrogel properties through succinylation.

Rational design of agarose/dextran composite microspheres with tunable core-shell microstructures for chromatographic application

A new type of core-shell microsphere was prepared by a pre-crosslinking method, consisting of cross-linked agarose microspheres as the core and agarose-dextran as the shell. After optimizing the preparation process, the microspheres with a uniform particle size were obtained and characterized using cryo-scanning electron microscopy to determine their surface and cross-sectional morphology. Results from flow rate-pressure and chromatographic performance tests showed that the core-shell agarose microspheres were supported by the core microspheres and composed of composite polysaccharides, forming an interpenetrating polymer network structure as a hard shell. The core-shell agarose microspheres showed a 300.5 % increase in linear flow rate compared to composite polysaccharide microspheres prepared from shell materials and a 141.5 % increase compared to 6 % agarose microspheres. Additionally, the large pore structure of the shell combined with the fine pore structure of the core improved the material separation efficiency in the range of 0.1-2000 kDa. These findings suggest that core-shell natural polysaccharide microspheres have great potential as a separation chromatographic medium.

Progress of ligand-modified agarose microspheres for protein isolation and purification

Proteins are the material basis of life and the primary carriers of life activities, containing various impurities that must be removed before use. To keep pace with the increasing complexity of protein samples, it is essential to constantly work on developing new purification technologies for downstream processes. While traditional downstream purification methods rely heavily on protein A affinity chromatography, there is still a lot of interest in finding safer and more cost-effective alternatives to protein A. Many non-affinity ligands and technologies have also been developed in biological purification recently. Here, the current status of biotechnology and the progress of protein separation technology from 2018 to 2023 are reviewed from the aspects of new preparation methods and new composite materials of commonly used separation media. The research status of new ligands with different mechanisms of action was reviewed, including the expanded application of affinity ligands, the development prospect of biotechnology such as polymer grafting, continuous column technology, and its new applications.

Application of cellulose to chromatographic media: Cellulose dissolution, and media fabrication and derivatization

As the cornerstone of chromatographic technology, the development of high-performance chromatographic media is a crucial means to enhance the purification efficiency of biological macromolecules. Cellulose is a popular biological separation medium due to its abundant hydroxyl group on the surface, easy modification and, weak non-specific adsorption. In this paper, the development of cellulosic solvent systems, typical preparation methods of cellulosic chromatographic media, and the enhancement of chromatographic properties of cellulosic chromatographic media by polymeric ligand grafting strategies and their mechanism of action are reviewed. Ultimately, based on the current research status, a promising outlook for the preparation of high-performance cellulose-based chromatographic media was presented.

Extraction, Modification and Biomedical Application of Agarose Hydrogels: A Review

Numerous compounds present in the ocean are contributing to the development of the biomedical field. Agarose, a polysaccharide derived from marine red algae, plays a vital role in biomedical applications because of its reversible temperature-sensitive gelling behavior, excellent mechanical properties, and high biological activity. Natural agarose hydrogel has a single structural composition that prevents it from adapting to complex biological environments. Therefore, agarose can be developed into different forms through physical, biological, and chemical modifications, enabling it to perform optimally in different environments. Agarose biomaterials are being increasingly used for isolation, purification, drug delivery, and tissue engineering, but most are still far from clinical approval. This review classifies and discusses the preparation, modification, and biomedical applications of agarose, focusing on its applications in isolation and purification, wound dressings, drug delivery, tissue engineering, and 3D printing. In addition, it attempts to address the opportunities and challenges associated with the future development of agarose-based biomaterials in the biomedical field. It should help to rationalize the selection of the most suitable functionalized agarose hydrogels for specific applications in the biomedical industry.

Fabrication of copolymer brushes grafted superporous agarose gels: Towards the ultimate ideal particles for efficient affinity chromatography

A composite immobilized-metal affinity agarose particle was designed for the selective separation and purification of histidine-tagged proteins from complicated biological samples. The composite particle was constructed using superporous agarose particles as supporting matrix, flexible copolymer brushes as scaffolds to render higher ligand densities, and Ni²⁺-chelated iminodiacetic acids as recognition elements. Superporous agarose composite particles endow high permeability and interfering substance tolerance. The copolymer brush was prepared by surface-initiated atom transfer radical polymerization of N-isopropylacrylamide and glycidyl methacrylate, followed by iminodiacetic acids and Ni²⁺ ions. The physical and chemical properities of the composite particle were thoroughly investigated. The composite particles were shown to be able to selectively separate histidine-tagged recombinant proteins in the presence of high quantities of interfering chemicals in a model protein-binding experiment. By altering the temperature, the protein binding of the composite particles can be modulated. The superporous agarose particles supported polymer brush enables fast and efficient separation and purification of target proteins with high permeability, low backpressure, and high interfering matrix tolerance, which pave the path for bioseparation through designing and fabrication of novel agarose particles-based functional materials.

Macroporous chitin microspheres prepared by surfactant micelle swelling strategy for rapid capture of lead (II) from wastewater

Heavy metal pollution of water source continues to be one of the most serious environmental problems which have attracted major global concern. Here, a macroporous chitin microsphere is prepared by surfactant micelle swelling strategy followed by modification with tetraethylenepentamine for Pb²⁺ removal from wastewater. The resultant adsorbent not only exhibits fast adsorption kinetic (>80% of its equilibrium uptake within 20 min) but also has high adsorption capacity of 218.4 ± 6.59 mg/g and excellent reusability (>75% of its initial adsorption capacity after five adsorption/desorption cycles). More importantly, under the continuous operating mode, the adsorbent can treat about 39,000 kg water/kg adsorbent, and the Pb²⁺ concentration decreases from 2000 μg/L to smaller than 10 μg/L, meeting the drinking water standard recommended by the World Health Organization (10 μg/L). All results indicate that the tetraethylenepentamine-modified macroporous chitin microspheres have great potential in the treatment of heavy metal contamination.

Manipulation of pore structure during manufacture of agarose microspheres for bioseparation

Agarose microspheres with a controllable pore structure were manufactured by varying agarose types and crosslinking degrees. Various agarose could tailor the gel formation of microspheres matrix and thus affect the final pore structures. Small pores in microspheres could be fabricated by agarose with a higher molecular weight, which was demonstrated by the packed column with lower distribution coefficient (Kav ) values measured by gel filtration chromatography. Further, higher Kav values also demonstrated that more and larger pores were formed with increasing the crosslinking degree of agarose microspheres. Either using agarose with a high molecular weight or increasing the crosslinking degree would finally lead to the enhancement of the flow rate during flow performance of packed column as necessary for improving separation efficiency. This provides a foundation for high-resolution chromatography with a controllable separation range as beneficial for downstream process.