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Biomedical Application of Membranes in Bioartificial Organs and Tissue Engineering
Published in Severian Dumitriu, Valentin Popa, Polymeric Biomaterials, 2020
Thomas Groth, Xiao-Jun Huang, Zhi-Kang Xu
The current review is separated into two major parts. The first section will give a comprehensive overview on how typical polymer membranes for biomedical and technical applications are prepared and how essential membranes features like morphology, transport, and surface properties can be tailored. It will also show how surface modifications can be used to achieve membrane properties that allow adsorption of specific molecules, but providing also attachment sites for cells. The second section of this review will focus on a few selected biomedical applications of polymer membranes. Since conventional therapeutic applications of polymer membranes in the treatment of ESRD by hemodialysis, hemofiltration, or for blood oxygenation have been reviewed in many other articles, these applications will be not further discussed here. However, the review will give a few examples on the application of membranes in the field of bioartificial organs, with emphasis on liver replacement and tissue engineering of skin.
Recent Development of Hemodialysis Membrane Materials
Published in Stephen Gray, Toshinori Tsuru, Yoram Cohen, Woei-Jye Lau, Advanced Materials for Membrane Fabrication and Modification, 2018
Muhammad Irfan, Masooma Irfan, Ani Idris, Ghani ur Rehman
PES is considered a new generation material, widely utilized in a number of blood purification devices such as plasma collectors, hemofiltration, plasmapheresis, hemodiafiltration, and hemodialyzers (Kokubo et al., 2015; Nissenson and Fine, 2016). The PES based membranes in dialyzers hold consistent, larger, densely and distributed pores, which improves the selectivity of low molecular weight proteins and promotes the removal of B2-m with nominal albumin loss. Moreover, PES dialysis membranes showed the highest standard of biocompatibility and endotoxin retaining features upon modifications (Krieter and Lemke, 2011). Although the commercial share of PSf based dialyzers is currently higher than PES dialyzers, this trend is predicted to discontinue because nephrologists recently detected the presence of BPA in the blood from the PSf based dialyzer. Unlike PSf, PES is a BPA free material (Huang et al., 2012; Vandentorren et al., 2011). However, PES membranes must also be modified with mono-, di-, and triblock of additives to improve the targeted characters as shown in Table 19.3. Figures 19.2 and 19.3 represent the chemical formulation of some modifiers and their schematic attachment to different polymers.
Membranes for Separation Processes
Published in Takeshi Matsuura, Synthetic Membranes and Membrane Separation Processes, 2020
Suppose there are two kinds of solutes, one represented by a closed circle and the other represented by an open circle, in Figure 1.8. Suppose also that the solute represented by a closed circle cannot pass through a membrane, while the solute represented by an open circle can. When a solution that contains both solutes is fed to the left side of the membrane from the bottom of the chamber (see Figure 1.8) while the solvent (usually water) is fed to the other side of the membrane from the top of the chamber, only the solute represented by an open circle can be transferred from the left side to the right side of the membrane. The solute represented by the closed circle is left behind. Thus, the solute mixture can be separated. The separation process based on the above principle is called dialysis. This process is being used in the artificial kidney, to remove urea, ureic acid, and creatinine from blood. Figure 1.9 shows schematically a dialysis system for blood treatment. A solution with an osmotic pressure nearly equal to that of blood is supplied into the dialyzer to remove toxic substances from the blood. A monitor is attached to control the dialyzing conditions. Toxic substances of relatively low molecular weights can be removed effectively by the above hemodialysis system. However, some toxic substances with high molecular weights, such as β2-microglobulin, cannot be removed. Hemofiltration, in which ultrafiltration membranes are employed, can remove toxic substances with molecular weights ranging from 500 to tens of thousands.
A review on magnetic polymeric nanocomposite materials: Emerging applications in biomedical field
Published in Inorganic and Nano-Metal Chemistry, 2023
The therapeutic approaches of diseases are usually to antagonize or neutralize a special compound. However, most direct treatments eliminate the disease-causing factors. For patients suffering from renal insufficiency, the removal of toxic compound is performed by hemodialysis or hemofiltration. Recently, magnetic separation has been applied in blood purification. Magnetic nanoparticles are functionalized to selectively separate target compounds. Current studies mainly focus on in vitro removal of compounds from plasma or whole blood, such as heavy metal ions (lead,[289] uranyl ions,[290] cadmium[291]), small molecule drugs (diazepam,[292] digoxin[293]), and endotoxins.[294] To clarify the biological/therapeutic relevance of the toxic compound removal achieved by magnetic separation-based blood purification, in vivo studies are necessary to demonstrate the applicability in clinic.[295] Herrmann et al.[296] reported in vivo magnetic blood purification from living rats. The ultra-strong magnetic nanoparticles are modified by specific ligands (iminodiacetic acid-based chelator for heavy metal ion separation and digoxin antibody FAB for digoxin separation) as magnetic carriers to rapidly removal toxins from extracorporeal blood circulation. This device has three parts: the left carotid artery is catheterized and connected through extracorporeal tubing to the left external jugular vein. Blood is then pumped through the extracorporeal circuit and functionalized magnetic nanoparticles are continuously injected into the circulating blood through a silicone injection port. The magnetic nanoparticles are collected and separated from the re-circulating blood using a magnetic separation unit before the blood enters the external jugular vein. As a result, over 40% of the toxin was removed within the first 10 minutes and over 75% within 40 minutes.[296]