Fabrication and characterization of cellulose acetate/hydroxyapatite composite membranes for the solute separations in Hemodialysis

Crown ether-functionalized cellulose acetate membranes with potential applications in osseointegration

Due to its inherent properties and wide availability, cellulose acetate is an extremely competitive candidate for the production of polymeric membranes. However, for best results in particular applications, membrane modification is required in order to minimize unwanted interactions and introduce novel characteristics to the pristine polymer. In this study, the surface of commercial cellulose acetate membranes was functionalized with 4'-aminobenzo-15-crown-5 ether, using a covalent bonding approach. The main goal was the improvement of the membranes biomineralization ability, thus making them prospective materials for bone regeneration applications. The proposed reaction mechanism was confirmed by XPS and NMR analysis while the presence of the functionalization agents in the membranes structure was showed by ATR FT-IR and Raman spectra. The effects of the functionalization process on the morphology, thermal and mechanical properties of the membranes were studied by SEM, TGA and tensile tests. The obtained results revealed that the cellulose acetate membranes were successfully functionalized with crown ether and provided a good understanding of the interactions that took place between the polymer and the functionalization agents. Moreover, promising results were obtained during the Taguchi biomineralization studies. SEM images, EDX mapping and XRD spectra indicating that the CA-AB15C5 membranes have a superior Ca²⁺ ions retention ability, this causing an accentuated calcium phosphate deposition on the modified polymeric fibers, compared to the neat CA membrane.

Cellulose acetate-polyvinyl alcohol blend hemodialysis membranes integrated with dialysis performance and high biocompatibility

Hemodialysis considered as therapy of end-stage renal disease (ESRD) for the separation of protein and uremic toxins based on their molecular weights using semi-permeable membranes. Cellulose Acetate (CA) hemodialysis membrane has been widely used in the biomedical field particularly for hemodialysis applications. The main issue of CA membrane is less selectivity and hemocompatibility. In this study, to enhance the filtration capability and biocompatibility of CA hemodialysis membrane modified by using Polyvinyl Alcohol (PVA) and Polyethylene Glycol (PEG) as additives. CA-PVA flat sheet membranes were cast by phase inversion method, and separation was done by dead-end filtration cell. The synthesized membranes were described in terms of chemical structure using Fourier Transform Infrared Spectroscopy (FTIR) and morphology by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), pure water flux, solute permeation, and protein retention. Biocompatibility of the membranes was tested by the platelet adherence, hemolysis ratio, thrombus formation, and plasma recalcification time. SEM images exposed that the CA-PVA membrane has a uniform porous structure. 42.484 L/m² h is the maximum pure water flux obtained. The CA-PVA rejected up to 95% of bovine serum albumin (BSA). A similar membrane separated 93% of urea and 89% of creatinine. Platelet adhesion and hemolysis ratio of casted membranes were less than the pure CA membrane. Increased clotting time and less thrombus formation on the membrane's surface showed that the fabricated membrane is biocompatible. CA-PVA hemodialysis membranes are more efficient than conventional reported hemodialysis membranes. It revealed that CA-PVA is high performing biocompatible hemodialysis membrane.

Biocompatibility performance evaluation of high flux hydrophilic CO3Ap/HAP/PSF composite membranes for hemodialysis application

Carbonate apatite/hydroxyapatite (CO3Ap/HAP) additive was obtained by calcination of wasted chicken bones at 900°C. Intermolecular attraction exists between CO3Ap/HAP additive and blended polysulfone (PSF) polymer. Electron dispersive X-ray (EDX) and FTIR analysis were carried out to check the elemental composition and bonding chemistry of prepared additive. The instantaneous demixing process generated consistent finger-like networks in CO3Ap/HAP/PSF-based composite membranes while sponge-like structure was shown by PSF as revealed by SEM images. The increase in weight % of additive loading is also confirmed by EDX analysis. Furthermore, the interaction mechanism of CO3Ap/HAP additive with polysulfone medium was analyzed by FTIR exploration. The water absorption experiment defined a 93% expansion in hydrophilic performance. Change in porosity occurs with additive loading and pure water permeation flux improved up to 11 times. Approximately, antifouling results revealed that 87% of water flux was recovered after treating with a protein solution, whereas a 30% improvement in antifouling capability in case of bovine serum albumin solution occurred. In vitro cytotoxicity, and clotting times study was carried out to evaluate virulent behavior and anticoagulation activity of formulated membranes.

Asymmetric Cellulosic Membranes: Current and Future Aspects

In this paper, we report our attempt to elaborate on cellulose-based materials and their potential application in membrane science, especially in separation applications. Furthermore, the cellulosic membrane has received attention for potential use as biomaterials such as novel wound-dressings and hemodialysis materials. In this mini-review, we mainly focus on the separation and antimicrobial properties of cellulosic membranes and the advanced synthesis/processing methods for superior functional quality for various potential applications. Finally, we conclude with the market and the impact of developments of future expectations.

Recent Advances in Applications of Cellulose Derivatives-Based Composite Membranes with Hydroxyapatite

The development of novel polymeric composites based on cellulose derivatives and hydroxyapatite represents a fascinating and challenging research topic in membranes science and technology. Cellulose-based materials are a viable alternative to synthetic polymers due to their favorable physico-chemical and biological characteristics. They are also an appropriate organic matrix for the incorporation of hydroxyapatite particles, inter and intramolecular hydrogen bonds, as well as electrostatic interactions being formed between the functional groups on the polymeric chains surface and the inorganic filler. The current review presents an overview on the main application fields of cellulose derivatives/hydroxyapatite composite membranes. Considering the versatility of hydroxyapatite particles, the hybrid materials offer favorable prospects for applications in water purification, tissue engineering, drug delivery, and hemodialysis. The preparation technique and the chemical composition have a big influence on the final membrane properties. The well-established membrane fabrication methods such as phase inversion, electrospinning, or gradual electrostatic assembly are discussed, together with the various strategies employed to obtain a homogenous dispersion of the inorganic particles in the polymeric matrix. Finally, the main conclusions and the future directions regarding the preparation and applications of cellulose derivatives/hydroxyapatite composite membranes are presented.