Biocompatible Membranes Research Articles

Water desalination using nanocelluloses/cellulose derivatives based membranes for sustainable future

Seawater desalination by utilizing a membrane-based technology is a crucial step to overcome the freshwater shortage in some regions of the world. However, the durability and performance of membranes rely on the type of fillers and materials utilized for the fabrication of the membrane. Since low-cost cellulose or its derivatives have been extensively used for the development of membranes in the last few years, so this review article has been focused on the exploration of the endeavours made by scientists for the development and improvement of biocompatible membranes utilizing distinctive cellulose-based materials. In particular, cellulosic materials such as the cellulose nanofibres, cellulose nanocrystals, bacterial nano cellulose and diverse cellulose derivatives exhibit different properties and structures, but all of these have been found to enhance the porosity, pore size, hydrophilic character and thus ultimately salt-removal capability and water permeability of the membrane. In this article, we have also analysed, the impact of chemical functionalization or loading of inorganic fillers onto the performance of cellulosic membranes utilized in different technologies such as reverse osmosis, forward osmosis, solar desalination, etc. The economic empowerment of cellulosic membranes not just relies on the fabrication steps, yet additionally on their potential in water desalination.

Topical electrospun patches loaded with oil for effective gamma linoleic acid transport and skin hydration towards atopic dermatitis skincare

Atopic dermatitis is a common disease that affects around 20 % of children. One of the supportive therapies is long-term skin hydration which can be obtained by applying specially designed patches. Therefore, in this work, polyimide (PI) electrospun membranes as patches for atopic skin hydration were studied. PI fibers of diameter 500 ± 70 nm were assessed for biocompatibility using murine fibroblasts, NIH 3T3, and evaluated with scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and MTS assay. The biocompatible PI membranes were mechanically tested and showed very high stretchability, above 350 %. These features, combined with a high membrane porosity of 95.6 %, make them excellent materials for skin patches. By loading the membranes with 10 µl blackcurrant seed oil rich in 11–19 % of gamma linoleic acid (GLA), we obtained skin patches that allow long-term hydration. Patches were assessed in vivo with skin hydration tests over 6 h and compared to numerical simulation of GLA release to the skin. The results obtained indicate the great potential of the electrospun PI patches for atopic skin care applications.

Development and Characterization of Biocompatible Membranes from Natural Chitosan and Gelatin for Pervaporative Separation of Water-Isopropanol Mixture.

Natural polymers have attracted a lot of interest in researchers of late as they are environmentally friendly, biocompatible, and possess excellent characters. Membranes forming natural polymers have provided a whole new dimension to the separation technology. In this work, chitosan-gelatin blend membranes were fabricated using chitosan as the base and varying the amount of gelatin. Transport, mechanical, and surface characteristics of the fabricated membranes were examined in detail by means of the characterizing techniques such as Fourier transform infrared spectroscopy, differential scanning colorimetry, wide angle X-ray diffraction, scanning electron microscope, and thermogravimetric analysis. In order to analyze the water affinity of the developed blend chitosan-gelatin membranes, the percentage degree of swelling was examined. Out of the fabricated membranes, the membrane loaded with 15 mass% of gelatin exhibited the better pervaporation performance with a pervaporation separation index value of 266 at 30 °C for the solution containing 10% in terms of the mass of water, which is the highest among the contemporary membranes. All the fabricated membranes were stable during the pervaporation experiments, and permeation flux of water for the fabricated membranes was dominant in the overall total permeation flux, signifying that the developed membranes could be chosen for efficient separation of water–isopropanol mixture on a larger scale.

Preparation of Mg/PCL electrospun membranes and preliminary study

Magnesium (Mg) metal and its alloy degradation product magnesium ion (Mg2+) can stimulate the metabolic activity of bone cells, which is beneficial to bone growth and healing. With biodegradable polycaprolactone (PCL) and magnesium particles as raw materials, electrospinning technology is used to prepare electrospun membrane materials doped with magnesium particles. Meanwhile, the scanning electron microscope, X-ray diffraction analysis technology and microcomputer-controlled electronic universal testing machine are adopted to analyze the physical and chemical properties of the material. The biocompatibility of electrospun membranes and their potential to induce osteogenic differentiation of human dental pulp stem cells (hDPSCs) were evaluated by in vitro cell experiments. The results showed that magnesium/PCL electrospun membranes doped with magnesium particles were successfully prepared with electrospinning technology, and the material has a good porous structure. Magnesium/PCL electrospun membranes have good biocompatibility and have the potential to induce osteogenic differentiation of hDPSCs. Among them, the effects of 10% magnesium/PCL electrospun membranes were the most obvious. Clinically, these materials provide new ideas for the restoration of alveolar bone defects and provide an experimental basis for the realization of alveolar bone regeneration.

Enhanced adsorption and biocompatibility of polysulfone hollow fibre membrane via the addition of silica/alpha-mangostin hybrid nanoparticle for uremic toxins removal

In this study, a highly biocompatible adsorptive membrane is developed for haemodialysis application. Silica/α-mangostin hybrid nanoparticle was incorporated into polysulfone (PSf) based membrane to enhance the biocompatibility and the adsorption capacity of the membrane. The PSf based membranes were fabricated via dry-wet phase inversion technique and characterised based on scanning electron microscopy and contact angle measurement. The effects of silica/α-mangostin nanoparticle incorporation into PSf membrane were evaluated in terms of permeability, p-cresol adsorption capacity, urea, and creatinine removal capabilities, bovine serum albumin rejection and p-cresol dynamic adsorption. The biocompatibility assessment was done based on platelet adhesion, antioxidant properties, and complement activation of the membrane. The incorporation of the nanoparticle into PSf based membrane helped to smoothen the surface of the membrane and enhanced its hydrophilicity of the membrane by 12.54%. The presence of silica/α-mangostin in the membrane enhanced the adsorption capacity of the membrane by 20.92% with adsorption capacity of 55.64 mg/g at 500 mg/L initial concentration. The modified PSf membrane had also successfully improved the biocompatibility of the membrane by enhancing the scavenging activity of hydrogen peroxide and nitrogen oxide by 61.8% and 36%, respectively and inhibited the formation of C5a by 27.27%. The developed biocompatible PSf based adsorptive membrane has a good potential to be used for haemodialysis application.

Synthesis and characterization of Dextran, poly (vinyl alcohol) blend biopolymer electrolytes with NH4NO3, for electrochemical applications

ABSTRACT New biocompatible biopolymer membranes have been synthesized from naturally occurring bacterial polysaccharide Dextran, which is efficacious versatile polymer known for medicinal applications. In the present study, biodegradable solid polymer electrolytes based on Dextran:Poly vinyl alcohol (PVA) with different composition of ammonium nitrate (NH4NO3) are prepared by solution casting technique with double distilled water as a solvent. The prepared polymer membranes have been characterized by various techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetric (DSC), AC impedance, linear sweep voltammetry (LSV), and transference number measurement. The amorphous nature of the polymer membrane is enhanced due to the addition of ammonium nitrate has been confirmed by X-ray diffraction analysis. The complex formation between the host polymer and the salt has been studied by Fourier transform infrared spectroscopy. The highest ionic conductivity of 1.66 × 10−3 S/cm for the composition 700 mgDextran:300 mgPVA:450 mgNH4NO3 has been observed by AC impedance spectroscopy at room temperature. The electrochemical stability of the highest conducting polymer electrolyte (700 mgDextran:300 mgPVA:450 mgNH4NO3) has been observed as 3.32 V by Linear sweep voltammetry. From Wagner’s polarization method transference number of highest conducting polymer electrolyte has been calculated as 0.99. Finally primary proton battery has been constructed using the highest conducting polymer membrane of 700 mgDextran:300 mgPVA:450 mgNH4NO3. Its open circuit voltage is measured as 1.51 V and its performance is studied.

Silicon Carbide-Gated Nanofluidic Membrane for Active Control of Electrokinetic Ionic Transport.

Manipulation of ions and molecules by external control at the nanoscale is highly relevant to biomedical applications. We report a biocompatible electrode-embedded nanofluidic channel membrane designed for electrofluidic applications such as ionic field-effect transistors for implantable drug-delivery systems. Our nanofluidic membrane includes a polysilicon electrode electrically isolated by amorphous silicon carbide (a-SiC). The nanochannel gating performance was experimentally investigated based on the current-voltage (I-V) characteristics, leakage current, and power consumption in potassium chloride (KCl) electrolyte. We observed significant modulation of ionic diffusive transport of both positively and negatively charged ions under physical confinement of nanochannels, with low power consumption. To study the physical mechanism associated with the gating performance, we performed electrochemical impedance spectroscopy. The results showed that the flat band voltage and density of states were significantly low. In light of its remarkable performance in terms of ionic modulation and low power consumption, this new biocompatible nanofluidic membrane could lead to a new class of silicon implantable nanofluidic systems for tunable drug delivery and personalized medicine.

Tuning Electrospun Substrate Stiffness for the Fabrication of a Biomimetic Amniotic Membrane Substitute for Corneal Healing.

Corneal blindness is the fourth most common cause of vision impairment worldwide with a high incidence in global south countries. A recently developed surgical technique for treating corneal blindness is simple limbal epithelial transplantation (SLET), which uses small pieces of healthy limbal tissue (limbal explants) delivered to the damaged eye using the human amniotic membrane (AM) as a carrier. SLET relies on the use of tissue banks for the AM that reduces the availability of the technique. Replacing the AM with a synthetic membrane is key to making SLET more accessible to those who need it. Previous research has demonstrated the suitability of electrospun poly(lactide-co-glycolide) (PLGA) scaffolds as AM substitutes, and here, we report how these membranes can be tailored to mimic fundamental AM mechanical properties. To modify the stiffness of PLGA electrospun membranes, we explored different electrospinning solvent systems (1,1,1,3,3,3,-hexafluoroisopropanol (HFIP), dichloromethane (DCM), chloroform, and N,N-dimethylformamide (DMF)) and the use of plasticizers (PEG400 and glycerol). PEG400 was found to reduce stiffness from 60 MPa to around 4 MPa, approaching the values shown by the native AM. The biocompatibility of membranes with and without PEG400 was found to be comparable, and cell outgrowth from rabbit/porcine explants was successfully observed on the materials after 3 weeks. This research underpins the manufacture of next-generation fibrous biomimetic membranes that will ultimately be used as amniotic membrane substitutes for biomedical applications including SLET.

Implantation of multiscale silk fibers on poly (lactic acid) fibrous membrane for biomedical applications

Despite that poly (lactic acid) (PLA) has satisfactory biodegradation in vivo, its application in biomedicine is restricted due to its unsatisfactory cytocompatibility. Silk fiber (SF) has outstanding biocompatibility and silk fibroin protein obtained from silk by degumming has good hydrophilicity. Therefore, combining the PLA and silk can improve hydrophilicity of PLA to apply as biomedical materials. In this study, different concentrations of sodium hypochlorite (NaClO) were used to separate the silk to obtain multiscale silk fibers (MSFs), which were implanted into the PLA electrospun fibrous membranes (EFMs). The morphology and structure of silk fibers separated by different concentrations of NaClO were studied by Zetasizer Nano ZS, UV spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Moreover, the biocompatibility of the surface-modified PLA composite membranes by MSFs was investigated by cell cultivation and proliferation. The results showed that the surface-modified PLA EFMs through MSF bundles obtained from NaClO split silk exhibited a certain improvement on PLA hydrophilicity and enhancement on cellular compatibility, which could have a broad prospect in the practical application of biomedical materials.

Fabrication of Thermochromic Membrane and Its Characteristics for Fever Detection.

Body temperature is an important indicator of the health status of the human body. Thus, numerous studies have been conducted in various fields to measure body temperature. In this study, a biocompatible thermochromic membrane that changes its color when the temperature becomes higher than the transition temperature for thermochromism was fabricated using an extrusion-based three-dimensional printing process. The printing material was prepared by mixing a thermochromic pigment and a thermoplastic polymer in various ratios. The effects of mixing ratio on the various properties of the fabricated membranes were experimentally investigated. It is presented that the fabricated lattice membrane had excellent thermochromic reaction, which was experimentally evaluated using a measurement of color brightness. The pigment content affected the diameter and surface morphology of the printed filament. The elastic modulus decreased, and thermochromic response became faster as the pigment concentration increased. Subsequently, a patch for fever detection was developed and then attached to the skin to demonstrate its color change according to body temperature. Results show that the fabricated thermochromic patch could be successfully applied to fever detection.

Structure and biological compatibility of polycaprolactone/zinc-hydroxyapatite electrospun nanofibers for tissue regeneration

Although guided tissue regeneration (GTR) is a useful tool for regenerating lost tissue as bone and periodontal tissue, a biocompatible membrane capable of regenerating large defects has yet to be discovered. This study aimed to characterize the physicochemical properties and biological compatibility of polycaprolactone (PCL) membranes associated with or without nanostructured hydroxyapatite (HA) (PCL/HA) and Zn-doped HA (PCL/ZnHA), produced by electrospinning. PCL, PCL/HA, and PCL/ZnHA were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). Nanoparticles of HA or ZnHA were homogeneously distributed and dispersed inside the PCL fibers, which decreased the fiber thickness. At 1 wt% of HA or ZnHA, these nanoparticles acted as nucleating agents. Moreover, HA and ZnHA increased the onset of the degradation temperature and thermal stability of the electrospun membrane. All tested membranes showed no cytotoxicity and allowed murine pre-osteoblast adhesion and spreading; however, higher concentrations of PCL/ZnHA showed less cells and an irregular cell morphology compared to PCL and PCL/HA. This article presents a cytocompatible, electrospun, nanocomposite membrane with a novel morphology and physicochemical properties that make it eligible as a scaffold for GTR.

An electro-spun tri-component polymer biomaterial with optoelectronic properties for neuronal differentiation

Optoelectronic biomaterials have recently emerged as a potential treatment option for neurodegenerative diseases, such as optic macular degeneration. Though initial works in the field have involved bulk heterojunctions mimicking solar panels with photovoltaics (PVs) and conductive polymers (CPs), recent developments have considered abandoning CPs in such systems. Here, we developed a simple antioxidant, biocompatible, and fibrous membrane heterojunction composed of photoactive polymer poly(3-hexylthiophene) (P3HT), polycaprolactone (PCL) and polypyrrole (PPY), to facilitate neurogenesis of PC-12 cells when photo-stimulated in vitro. The photoactive prototype, referred to as PCL-P3HT/PPY, was fabricated via polymerization of pyrrole on electro-spun PCL-P3HT nanofibers to form a membrane. Four experimental groups, namely PCL alone, PCL/PPY, PCL-P3HT and PCL-P3HT/PPY, were tested. In the absence of the CP, PCL-P3HT demonstrated lower cell survival due to increased intracellular reactive oxygen/nitrogen species production. PCL-P3HT/PPY rescued these cells by virtue of scavenging radicals, where the CP, PPY, acted as an antioxidant. Apart from having lower impedance, the material also enhanced neurogenesis of PC-12 cells when photo-stimulated, compared to the traditional PCL-P3HT. Lastly, the in vitro system with PC-12 was used to demonstrate the practicality of the material for potential use as a cellular patch in optic and nerve regeneration. This work demonstrated the importance of maintaining PV-CP heterojunctions while simultaneously providing an optoelectrical platform for neural and optical tissue engineering. Statement of significanceRegeneration and repair of injured nervous systems have always been a major clinical challenge. Stem cell therapy is a promising approach for nerve regeneration, and opto-electrical stimulation, which converts light into an electrical signal, has been shown to efficiently regulate stem cell behaviors with enhanced neurogenesis. We developed a micro-fibrous membrane, composed of photoactive polymer, P3HT, scaffold material PCL and conductive polymer PPY. Our heterojunction system improved cell survival via PPY quenching PCL-P3HT-generated cell-damaging reactive oxygen species. PPY also conducted electrons produced from light-stimulated P3HT to promote neurogenesis. This photoactive microfiber biomaterial has great potential as a highly biocompatible and efficient platform to wirelessly promote neurogenesis and survival. Our approach thus showed possibilities with respect to optical tissue engineering.

Atherosclerosis-calcification score and predictors of intra-dialytic hypotension.

Intra-dialytic hypotension episodes (ID-Hypos) cause significant reduction of dialysis efficiency and increased cardiovascular morbimortality. Atherosclerosis and vascular calcification are two closely inter-related processes that occur prematurely and progress aggressively in maintenance hemodialysis (MHD) patients. To study the predictors of ID-Hypos, particularly a novel combined atherosclerosis-calcification score (CACS) (0 to 6) obtained by adding the atherosclerosis score (AS) to a modified abdominal aortic calcification score (AACS), each ranging 0 to 3. In 60 adult MHD patients, AS was derived from ankle-brachial index and carotid ultrasound. AACS was modified from Kauppila score applied on lateral abdominal plain radiographs. The number of sessions complicated by ≥ 1 ID-Hypos over 14 weeks was recorded and correlated with CACS, ultrafiltration rate (UFR), and other hemodynamic and laboratory parameters. Patients developed a median of 10.5 ID-Hypos (IQR 5.75-14). The number of ID-Hypos had a statistically significant positive correlation with CACS (r = 0.291, p = 0.024), but not with its individual components. AACS had a statistically significant positive correlation with s. phosphorus and calcium-phosphorus product. On multivariate analysis, the most significant independent predictors of ID-Hypos were high UFR, high CACS, and low hemoglobin. Serum C-reactive protein had a positive correlation with ID-Hypos that was lost in the adjusted models. High UFR, CACS, and anemia are significant predictors of ID-Hypos. CACS may help in quantifying vascular pathology and characterizing MHD patients at highest risk for ID-Hypos, those who would be prioritized for potential preventive measures like biocompatible membranes or hemodiafiltration. A background of chronic inflammation may underlie and link patient-related ID-Hypos risk factors.

Robust Electrospun Nanofibers from Chemosynthetic Poly(4-hydroxybutyrate) as Artificial Dural Substitute.

Bioresorbable poly(4-hydroxybutyrate) (P4HB) may fulfill the specific requirements that are necessary for a dural substitute, including its high elasticity, long-term strength retention properties, and the biocompatibility without significant accumulation of acidic degradation products. However, commercial P4HB can only be produced by the bacterial fermentation, which limits its applications in the cerebrospinal system due to higher endotoxin restriction. Meanwhile, P4HB can be prepared via the ring-opening polymerization of γ-butyrolactone. In this contribution, high molecular weight P4HB from chemosynthesis is electrospun into fibrous membrane, showing good mechanical properties that match the natural dura mater. Such P4HB membrane induces fast cellular migration, adhesion, and proliferation of fibroblasts in vitro. Subcutaneous implantation in rats demonstrates excellent biocompatibility of the P4HB membrane with proper biodegradation behaviors. After implantation in the rabbit dural defect model as an onlay graft, the P4HB membranes prevent cerebrospinal fluid leakage and regenerate dura tissue without detecting any local or systematic infections or foreign body responses. Thus, the electrospun P4HB membranes may be particularly useful as artificial dural substitutes to induce wound closure and tissue regeneration, which will be of great benefit to neurosurgery in the future.

Antibacterial Evaluation of Lithium-Loaded Nanofibrous Poly(L-Lactic Acid) Membranes Fabricated via an Electrospinning Strategy.

Lithium (Li) reportedly has anti-bacterial properties. Thus, it is an ideal option to modify barrier membranes used for guided bone regeneration to inhibit the bacterial adhesion. The aims of this study were to fabricate and characterize nanofibrous poly(L-lactic acid) (PLLA) membranes containing Li, and investigate their antibacterial effects on Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in vitro. Li (5%Li, 10%Li, and 15%Li)-loaded nanofibrous PLLA membranes were fabricated using an electrospinning technique, and characterized via scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, a contact angle measuring device, and a universal testing machine. Sustained release of Li ions was measured over a 14-day period and biocompatibility of the Li-PLLA membranes was investigated. Evaluation of bacterial adhesion and antibacterial activity were conducted by bacterial colony counting, LIVE/DEAD staining and inhibition zone method using P.gingivalis and A.actinomycetemcomitans. Of the three Li-loaded membranes assessed, the 10%Li-PLLA membrane had the best mechanical properties and biocompatibility. Adhesion of both P.gingivalis and A.actinomycetemcomitans on Li-PLLA membranes was significantly lower than adhesion on pure PLLA membranes, particularly with regard to the 10%Li and 15%Li membranes. Significant antibacterial activity of Li-PLLA were also observed against according to the inhibition zone test. Given their better mechanical properties, biocompatibility, and antibacterial activity, PLLAs with 10%Li are a better choice for future clinical utilization. The pronounced antibacterial effects of Li-loaded PLLA membranes sets the stage for further application in guided bone regeneration.

Characterization and Determination of the Biocompatibility of Porous Polytetrafluoroethylene Membranes Fabricated via Electrospinning

The structure and properties of polytetrafluoroethylene (PTFE) polymeric membranes obtained by electrospinning from a suspension of PTFE in a solution of polyvinyl alcohol (PVA) with subsequent thermal treatment were presented. The effect of the PTFE suspension ratio in spinning solutions on the morphology, crystal structure, chemical composition, strength, and cytotoxicity of the formed PTFE membranes was evaluated. We found that a decrease in the PTFE suspension content in spinning solutions leads to a decrease in the number of defects in the membrane fibers, which increasing the strength and elongation. Membranes made from spinning solutions with a lower content of PTFE suspension have a higher degree of crystallinity and a more perfect crystal structure. It has been suggested that the products of PVA destruction during the heat treatment of PTFE/PVA membranes are capable of plasticizing effects on PTFE particles, improving the strength of PTFE membranes. The membranes after thermal treatment were not cytotoxic regardless of the PTFE suspension content in the spinning solutions. High biocompatibility of membranes was established during implantation into soft tissues.

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.

POS-554 HEMODIALYSIS: CASE SERIES OF SIGNIFICANT THROMBOCYTOPENIA ASSOCIATED WITH DIALYZER CARTRIDGE SYSTEM

Thrombocytopenia, has been mentioned in recent case studies as common reaction during hemodialysis, could be associated with the dialyzer cartridge system. Here, the NxStage pre-attached dialyzer-cartridge used was CAR-172 cartridge express products, gamma-ray sterilized that includes an integrated dialyzer with biocompatible glycerin-free polyethersulfone membrane (PUREMA® H). NxStage system also has standard cartridge CAR-124 which allows replacement or connection for alternate dialyzers as per patients’ clinical requirement.

Evaluation of Guided Bone Regeneration in Critical Defects Using Bovine and Porcine Collagen Membranes: Histomorphometric and Immunohistochemical Analyses

Guided bone regeneration (GBR) is a technique used to facilitate bone regeneration, which uses a biocompatible membrane acting as a physical barrier to prevent the adjacent connective tissue from invading the bone defect. The aim of this study was to evaluate and compare the effectiveness of bovine and porcine collagenous membranes as barriers to connective tissue invasion during the repair of critical bone defects in rat calvaria, using histological, histometric, and immunohistochemical analyses. For this study, 72 rats were divided into three groups: clot group (CG), bovine collagen group (BCG), and porcine collagen group (PCG). Analyses were performed on days 7, 15, 30, and 60. The histological results showed that the PCG exhibited bone neoformation starting from day 7, and after 30 days of repair, the surgical defect was completely filled in some animals. For the BCG, there was little bone neoformation activity in the initial periods, and from day 30 onwards, there was an increase in bone neoformation, with a greater increase on day 60. The data obtained in the histometric analysis reveal that, on day 30, the neoformed bone area did not vary greatly between the PCG and the BCG, though both varied from the CG. By day 60, the PCG presented a greater area of neoformation than the BCG. These results were corroborated by the immunohistochemistry results. In view of the results obtained, it can be concluded that all membranes studied in this research promoted GBR.

Transport Studies of Biocompatible Polymeric Membrane and its Application in Lead Ion (Pb++) Absorption

Contamination of these heavy metal ions in water has also increased public concerns because of their toxicity even at lower concentrations, besides non-biodegradability and tendency of bioaccumulation. Biodegradable natural composite membrane systems based on Polycaprolactone, (PCL), salt and montmorillonite (MMT) clay have been synthesized by phase inversion technique for the application of biomedical, technical and heavy metal ion absorption. The composite membrane provides better thermal stability and other medical properties than the pure PCL polymer film. This work will be valuable for understanding of development and characterisation of membranes and their application in heavy metal absorption. The absorption of heavy metal from water is a result of chemical reaction or interaction between the heavy metals and (Si-OH i.e. silanol) and (Al-OH i.e. aluminol) groups. In addition, it is helpful in developing economic and high performance material. Polymer nanocomposite electrolyte membranes were studied by X-ray diffraction (XRD), Fourier transformed Infrared (FTIR) technique, Raman spectroscopy and Impedance analysis. The heavy metal absorption behaviour is studied by the FT-IR spectroscopy.