Novel dopamine-modified cellulose acetate ultrafiltration membranes with improved separation and antifouling performances

Enhanced Protein Separation Performance of Cellulose Acetate Membranes Modified with Covalent Organic Frameworks

As a porous crystalline material, covalent organic frameworks (COFs) have attracted significant attention due to their extraordinary features, such as an ordered pore structure and excellent stability. Synthesized through the aldehyde amine condensation reaction, TpPa-1 COFs (Triformylphloroglucinol-p-Phenylenediamine-1 COFs) were blended with cellulose acetate (CA) to form a casting solution. The TpPa-1 COF/CA ultrafiltration membrane was then prepared using the non-solvent-induced phase inversion (NIPS) method. The influence of TpPa-1 COFs content on the hydrophilicity, stability and filtration performance of the modified membrane was studied. Due to the hydrophilic groups in TpPa-1 COFs and the network structure formed by covalent bonds, the modified CA membranes exhibited higher hydrophilicity and lower protein adsorption compared with the pristine CA membrane. The porous crystalline structure of TpPa-1 COFs increased the water permeation path in the CA membrane, improving the permeability of the modified membrane while maintaining an outstanding bovine serum albumin (BSA) rejection. Furthermore, the addition of TpPa-1 COFs reduced protein adsorption on the CA membrane and overcame the trade-off between permeability and selectivity in CA membrane bioseparation applications. This approach provides a sustainable method for enhancing membrane performance while enhancing the application of membranes in protein purification.

An Innovative Surface Modification Technique for Antifouling Polyamide Nanofiltration Membranes

In this study, we developed a novel surface coating technique to modify the surface chemistry of thin film composite (TFC) nanofiltration (NF) membranes, aiming to mitigate organic fouling while maintaining the membrane's permselectivity. We formed a spot-like polyester (PE) coating on top of a polyamide (PA) TFC membrane using mist-based interfacial polymerization. This process involved exposing the membrane surface to tiny droplets carrying different concentrations of sulfonated kraft lignin (SKL, 3, 5, and 7 wt %) and trimesoyl chloride (TMC, 0.2 wt %). The main advantages of this surface coating technique are minimal solvent consumption (less than 0.05 mL/cm2) and precise control over interfacial polymerization. Zeta potential measurements of the coated membranes exhibited enhancements in negative charge compared to the control membrane. This enhancement is attributed to the unreacted carboxyl functional groups of the SKL and TMC monomers, as well as the presence of sulfonate groups (SO3) in the structure of SKL. AFM results showed a notable decrease in membrane surface roughness after polyester coating due to the slower diffusion of SKL to the interface and a milder reaction with TMC. In terms of fouling resistance, the membrane coated with a polyester composed of 7 wt % SKL showed a 90% flux recovery ratio (FRR) during Bovine Serum Albumin (BSA) filtration, showing a 15% improvement compared to the control membrane (PA). PE-coated membranes provided stable separation performance over 40 h of filtration. The sodium chloride rejection and water flux displayed minimal variations, indicating the robustness of the coating layer. The final section of the presented study focuses on assessing the feasibility of scaling up and the cost-effectiveness of the proposed technique. The demonstrated ease of scalability and a notable reduction in chemical consumption establish this method as a viable, environmentally friendly, and sustainable solution for surface modification.

A review of cellulose-based catechol-containing functional materials for advanced applications

With the increment in global energy consumption and severe environmental pollution, it is urgently needed to explore green and sustainable materials. Inspired by nature, catechol groups in mussel adhesion proteins have been successively understood and utilized as novel biomimetic materials. In parallel, cellulose presents a wide class of functional materials rating from macro-scale to nano-scale components. The cross-over among both research fields alters the introduction of impressive materials with potential engineering properties, where catechol-containing materials supply a general stage for the functionalization of cellulose or cellulose derivatives. In this review, the role of catechol groups in the modification of cellulose and cellulose derivatives is discussed. A broad variety of advanced applications of cellulose-based catechol-containing materials, including adhesives, hydrogels, aerogels, membranes, textiles, pulp and papermaking, composites, are presented. Furthermore, some critical remaining challenges and opportunities are studied to mount the way toward the rational purpose and applications of cellulose-based catechol-containing materials.

Biocompatible Cryogel with Good Breathability, Exudate Management, Antibacterial and Immunomodulatory Properties for Infected Diabetic Wound Healing

Due to the complex microenvironment and healing process of diabetic wounds, developing wound dressing with good biocompatibility, mechanical stability, breathability, exudate management, antibacterial ability, and immunomodulatory property is highly desired but remains a huge challenge. Herein, a multifunctional cryogel is designed and prepared with bio-friendly bacterial cellulose, gelatin, and dopamine under the condition of sodium periodate oxidation. Bacterial cellulose can enhance the mechanical stability of the cryogel by improving the skeleton supporting effect and crosslinking degree. The cryogel shows outstanding breathability and exudate management capability thanks to the interpenetrated porous structures. I2 and sodium iodides produced in situ by reduction of sodium periodate provide efficient antibacterial properties for the cryogel. The cryogel facilitates macrophage polarization from M1 to M2, thus regulating the immune microenvironment of infected diabetic wounds. With these advantages, the multifunctional cryogel effectively promotes collagen deposition and neovascularization, thus accelerating the healing of infected diabetic wounds.

1Progress, applications, challenges and prospects of protein purification technology

Protein is one of the most important biological macromolecules in life, which plays a vital role in cell growth, development, movement, heredity, reproduction and other life activities. High quality isolation and purification is an essential step in the study of the structure and function of target proteins. Therefore, the development of protein purification technologies has great theoretical and practical significance in exploring the laws of life activities and guiding production practice. Up to now, there is no forthcoming method to extract any proteins from a complex system, and the field of protein purification still faces significant opportunities and challenges. Conventional protein purification generally includes three steps: pretreatment, rough fractionation, and fine fractionation. Each of the steps will significantly affect the purity, yield and the activity of target proteins. The present review focuses on the principle and process of protein purification, recent advances, and the applications of these technologies in the life and health industry as well as their far-reaching impact, so as to promote the research of protein structure and function, drug development and precision medicine, and bring new insights to researchers in related fields.

Effect of Silica Sodalite Loading on SOD/PSF Membranes during Treatment of Phenol-Containing Wastewater

In this study, silica sodalite (SSOD) was prepared via topotactic conversion and different silica sodalite loadings were infused into the polysulfone (PSF) for application in phenol-containing water treatment. The composite membranes were fabricated through the phase inversion technique. Physicochemical characteristics of the nanoparticles and membranes were checked using a Scanning Electron Microscope (SEM), Brunauer Emmett-Teller (BET), and Fourier Transform Infrared (FTIR) for surface morphology, textural properties, and surface chemistry, respectively. A nanotensile test, Atomic Force Microscopy (AFM), and contact angle measurement were used to check the mechanical properties, surface roughness, and hydrophilicity of the membranes, respectively. SEM results revealed that the pure polysulfone surface is highly porous with large evident pores. However, the pores decreased with increasing SSOD loading. The performance of the fabricated membranes was evaluated using a dead-end filtration device at varying feed pressure during phenol-containing water treatment. The concentration of phenol in water used in this study was 20 mg/L. The pure PSF displayed the maximum phenol rejection of 95 55% at 4 bar, compared to the composite membranes having 61.35% and 64.75% phenol rejection for 5 wt.% SSOD loading and 10 wt.% SSOD loading, respectively. In this study, a novel Psf-infused SSOD membrane was successfully fabricated for the treatment of synthetic phenol-containing water to alleviate the challenges associated with it.