Polyethylene Glycol Membrane Research Articles

Swelling dynamics and chain structure of ultrathin PEG membranes in seawater

Polyethylene glycol (PEG) is widely utilized in marine antifouling materials; thus, the fundamental understanding of PEG characteristics in seawater is indispensable. Herein, a “membrane-seawater” separation chamber model is designed, and the molecular dynamics (MD) method is used to simulate the swelling process of PEG membranes in seawater; two characteristic lengths are developed from the concept of Gibbs surface to illustrate the relationship between seawater ions and PEG membranes; the amount of bound water in the hydration shell of PEG is calculated by experimental method. It is concluded that the water content of the PEG membrane in seawater is not much different from that of swelling in water; only the swelling rate changes; the seawater ions accelerate the swelling of the PEG membrane, but most gathered in the outer layer of PEG membrane; Ions change the distribution structure of the hydration layer, and the bound water of PEG decreases under the action of seawater ions. Moreover, the structure of the PEG chain in seawater has a change of “helix-ring”. The study of PEG in seawater will provide an effective supplement and theoretical basis for the modification design of PEG coating.

Enhancement of antifouling properties, metal ions and protein separation of poly(ether-ether-sulfone) ultrafiltration membranes by incorporation of poly ethylene glycol and n-ZnO

Composite polymeric membranes with enhanced anti-fouling properties, antimicrobial activities and flux were produced via the phase inversion technique using poly (ether-ether-sulfone) (PEES)/polyethylene glycol (PEG) and n-ZnO. SEM and ATR-FTIR spectroscopy were used to study the morphological and chemical properties of the resulting ultrafiltration membranes. PEG and n-ZnO concentration has an effect on membrane morphologies, ultrafiltration performance, thermal characteristics, metal ion separation studies, surface hydrophilicity and anti-fouling capabilities. The permeate flux increased when the PEG concentration was raised. This results revealed that adding PEG and n-ZnO to membranes increased their surface hydrophilicity and anti-fouling properties. The inclusion of 1.5 wt % n-ZnO and 5 wt % PEG to the pristine PEES membrane resulted in a higher flux of 233.76 L m-2 h−1, 70.09 % of water content, 47.46° of contact angle, the porosity of 30.20 %, and hydraulic resistance of 0.22 kPa/Lm−2h−1. Anti-fouling properties of the fabricated membrane were assessed using a model foulant BSA, which revealed a high flux recovery ratio value. As a result, the PEG and n-ZnO incorporated membrane is more hydrophilic than the virgin membrane. In addition, the prepared PEES/PEG/n-ZnO membrane showed a significant increase in metal ions and protein rejection. Furthermore, an antibacterial test of the membrane revealed that the PEG and n-ZnO composite membrane outperformed the bare PEES membrane in terms of antibacterial capabilities. Overall, the findings reveal that combining n-ZnO and PEG resulted in a membrane with improved anti-fouling capabilities and hydrophilicity, making it suitable for water purification.

Enhanced pervaporation performance of PEG membranes with synergistic effect of cross-linked PEG and porous MOF-508a

MOF-508a with moderate 1D channels and large pore cavity size, was successfully synthesized and firstly incorporated into polyethylene glycol (PEG) to prepare mixed matrix membranes (MMMs) for desulfurization via pervaporation. Four kinds of cross-linkers were employed to cure PEG polymers, and PEG membrane cured with oxalic acid acquired much better comprehensive pervaporation performance. The uniformly dispersed MOF-508a in PEG matrix interrupted the crystalline region and decreased PEG crystallization degree. MOF-508a might act as facilitated transport carriers for thiophene molecules based on coordination interaction between Zn2+ and S, and large pore cavities provided multi-scale transport pathways for thiophene molecules. Besides, the strong interaction between MOF-508a and PEG enhanced the interfacial compatibility, which might provide more selective transport pathways for small molecules. Owing to the synergistic effect of cross-linked PEG and porous MOF-508a, the MOF-508a/PEG-5 MMMs exhibited outstanding enrichment factor of 30.4 with permeation flux of 0.485 kg/m2h, which were 98 % and 110 % higher than those of pristine PEG membrane. The enrichment factor of MOF-508a/PEG out-performed most the ever-reported membranes, which might provide some new insight in designing high-performance MMMs by rationally achieving synergy of porous fillers and polymer matrix.

Enhanced desulfurization performance of polyethylene glycol membrane by incorporating metal organic framework MOF-505

• MOF-505/PEG mixed matrix membranes were prepared. • The filled MOF-505 provided extra free volume for the membranes. • The active metal sites of MOF-505 have selective adsorption for thiophene. • Both permeability and selectivity of the MOF-505/PEG MMMs were increased. The metal–organic framework MOF-505 particles were synthesized and incorporated into the polyethylene glycol (PEG) matrix to prepare mixed matrix membranes. A series of methods were used to characterize the structure and morphology of MOF-505 particles and membranes. The prepared MOF-505 had a well-developed pore structure, a large number of metal sites for selective adsorption of thiophene and good compatibility with polymer matrix. Accordingly, the desulfurization performance of the membrane was improved effectively. The effects of the content of MOF-505, operating temperature and feed sulfur content on membrane performance were investigated by pervaporation experiments. The membrane with 3 wt% MOF-505 showed the optimal desulfurization performance with a permeation flux of 2.66 kg/(m 2 ·h) and an enrichment sulfur factor of 8.15, which were increased by 158% and 25% versus pristine membrane, respectively.

Effect of Graphene Oxide on the Performance of Cellulose Acetate/ Polyethylene Glycol Membrane with Blending Method for Desalination of Brackish Water

Polymeric membrane must be strong during the reverse osmosis process. Carbon-based materials like carbon nanotubes (CNTs), graphene, and its derivative graphene oxide (GO) have strong mechanical strength, high resistance to strong acids/ alkaline and organic solvents, and easy in accessibility. In this study, GO were blendingd into Cellulose Acetate/ Polyethylene Glycol (CA/PEG) membranes prepared by phase inversion method. Performance of the membrane was evaluated from the water flux, salt rejection, and permeability. Morphology, hydrofilicity, tensile strength were isvestigated by using Scanning Electron Microscopy (SEM), Fourier-Transformed Infra-Red (FTIR) and contact angle analysis, and Dynamic Mechanical Analysis (DMA), respectively. The experiment results show that hydrophilicity and porosity increase with the addition of GO with the addition of 0.005% GO exhibits the highest value of them resulting membrane with better flux and salt rejection values as compared to the GO-free membrane. With the addition of 0.005 wt% GO resulted in salt rejection (%R) 83.3% and flux permeate (F) 2194 L/m2.h. and tensile strength of 0.0148 Mpa. Membrane with CA/PEG/GO has more advantages, where GO affects the porosity of the membrane by increasing the pore size such as fingers and reducing the thickness of the wall which will result in increased membrane performance ability.

Resorbable membrane of polyethylene glycol in Wistar rats for guided bone regeneration - Experimental study

Purpose: The aim of the present study was (1) to test whether or not the application of an in situ formed synthetic hydrogel, made of polyethylene glycol (PEG) used as a resorbable membrane for guided bone regeneration, will result in more amount of bone regeneration compared with an uncovered defect and (2) to evaluate if it can prevent the soft-tissue ingrowth into alveolar defects. Materials and Methods: Two critical size defects were created in seven Wistar rats. In the right side, an in situ formed hydrogel PEG membrane (Straumann MembraGel) was applied into the defect and the left one was kept empty as a control. After 60 days, animals were sacrificed and the calvarial bone was removed. The area of newly formed bone was determined by histomorphometrical analysis. For statistical analysis, the Mann-Whitney-U test was applied to model the amount of new bone formation. Results: The quantitative histomorphometric analysis obtained a percentage of newly formed bone for the test defects of 61,8% +/-22,2% and 53,8% +/-22,9% in the control group. The observed differences were not statistically significant. Conclusions The experimental PEG membrane was biocompatible and prevented soft-tissue ingrowth. There were no statistically significant differences between the groups.

Comparison of a polyethylene glycol membrane and a collagen membrane for the treatment of bone dehiscence defects at bone level implants-A prospective, randomized, controlled, multicenter clinical trial.

The aim of the present randomized, controlled clinical multicenter trial was to compare a polyethylene glycol (PEG) and a native collagen membrane (BG) for simultaneous guided bone regeneration at bony dehiscence-type defects around bone level titanium implants. The study enrolled 117 patients requiring implant treatment in the posterior maxilla or mandible with expected buccal bony dehiscence-type defects at the placed titanium implants. According to a parallel groups design, defects were filled with a synthetic bone filler and randomly assigned to either PEG or BG membrane. As primary parameter, the relative vertical bone fill was assessed at baseline and at re-entry after 6months of healing. As secondary parameters, the marginal bone level (MBL) was assessed radiographically and soft tissue conditions were recorded up to 18months postloading. Both groups showed comparable vertical bone fill revealing a relative change in defect height of 59.7% (PEG) and 64.4% (BG). The absolute mean reduction in defect size was 2.5mm in the PEG group and 3.2mm in the BG group. Although both groups revealed a statistically significant mean defect reduction (p<.001), a comparison between the two groups did not show statistical significances. The non-inferiority test with inferiority limit of -5% could not be rejected, based on the 90% confidence interval of the differences of the two means with lower limit -15.4%. After 18months, an MBL increase of 0.45±0.43mm in the PEG group and 0.41±0.81mm in the BG group was detected (p<.001). Soft tissue complications were observed in both groups without showing statistical significance. Both membranes supported bone regeneration at dehiscence-type defects and obtained vertical bone fill with a relative change in defect height of 59.7% (PEG) and 64.4% (BG); however, the non-inferiority of PEG could not be shown.

Optimization of Process Parameters using Response Surface Methodology for PCL based Biodegradable Composite Membrane for Water Purification

The biodegradability of polycaprolactone (PCL) and the anti-fouling property of TiO2 are utilized for the preparation of membranes for water treatment. Polyethylene glycol (PEG) is added to the polymeric solution to increase the pore formation in the membranes. The composition of PEG and TiO2 nanoparticles was optimized using the central composite design and response surface methodology. Quadratic models were developed for the responses porosity and contact angle, and the optimum compositions obtained for PEG and TiO2 were 6.24 and 1 wt%, respectively. The competency of the membrane for water treatment is studied using different characterization techniques such as TG analysis, FTIR to determine the chemical interactions, UTM to examine the mechanical strength, AFM for membrane roughness determination and morphological analysis using FESEM. A twofold increase in the overall porosity and a twentyfold reduction (approx.) in pore size were observed for the composite membrane from FESEM images. The anti-fouling ability of TiO2 resulted in a flux recovery of about 90% for the composite membrane compared to the PCL–PEG membrane after bovine serum albumin filtration. Also, the presence of TiO2 increased the reversible fouling component, which can be easily removed by cleaning/backwashing. Thus, the PCL–TiO2 combination would be a better alternative for the membranes used in water treatment applications.

In vitro endothelial differentiation evaluation on polycaprolactone-methoxy polyethylene glycol electrospun membrane and fabrication of multilayered small-diameter hybrid vascular graft.

During development of functional tissue engineered vascular graft, ensuring endothelialization at inner layer and mechanically strong outer layer is considered as challenging. The study objective was to fabricate a multilayered artificial blood vessel by dual syringe electrospinning technique. The presented graft was composed of polycaprolactone-methoxy polyethylene glycol which acts as an inner layer whereas Poly [4,4’-methylenebis(phenyl isocyanate)-alt-1,4-butanediol/di(propylene glycol)/polycaprolactone] (PUPCL) (12% w/v) was incorporated as the outer layer. To find out the optimum inner layer, different polycaprolactone-methoxy polyethylene glycol electrospun membranes varying methoxy polyethylene glycol content (0, 5, 10, 20, and 30% w/v) were prepared and evaluated. The characterizations revealed that blending of methoxy polyethylene glycol with polycaprolactone improved hydrophilicity and antithrombogenic properties compared to polycaprolactone or polyurethane polycaprolactone membrane. During in vitro assessment, the optimized polycaprolactone-20% methoxy polyethylene glycol membrane reinforced a greater differentiation of rat bone marrow stem cell into endothelial cells at both mRNA and protein levels by significantly inducing endothelial markers (CD31, Flk-1, and von Willebrand factor) expression. The polyurethane polycaprolactone membrane showed higher mechanical strength than polycaprolactone-methoxy polyethylene glycol while multilayered polycaprolactone-20% methoxy polyethylene glycol/polyurethane polycaprolactone vascular graft exhibited better result compared to single form. Therefore, the strong and bioactive polycaprolactone-20% methoxy polyethylene glycol/polyurethane polycaprolactone small diameter graft (&lt;2 mm) prepared by simple fabrication process could be a promising preliminary platform for vascular tissue engineering application studies.

A water-based mixing process for fabricating ZIF-8/PEG mixed matrix membranes with efficient desulfurization performance

In this article, ZIF-8 nanoparticles were synthesized in water and directly added to a polyethyleneglycol (PEG) aqueous solution (water-based mixing process) to prepare ZIF-8/PEG mixed matrix membranes (MMMs) for pervaporation desulfurization. The structure and properties of ZIF-8 particles were characterized by Fourier Transform-Infrared Spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and BET analysis. The surface composition and structural morphology of all ZIF-8/PEG MMMs were systematically investigated by FT-IR and SEM. The effect of ZIF-8 content on the pervaporation performance of ZIF-8/PEG membranes was investigated. Versus pure PEG membranes, both the total flux and the sulfur enrichment factor of the ZIF-8/PEG MMMs were remarkably increased. This phenomenon is attributed to the good compatibility between PEG and ZIF-8 particles and the high thiophene selective sorption of ZIF-8 particles (confirmed by molecular simulation). Optimal pervaporation performance was achieved at a 4 wt% loading of ZIF-8 particles with the flux of 1.96 kg/(m2 h) and the sulfur enrichment factor of 8.93. These increased by 397.46% and 18.75% versus pristine PEG membrane, respectively. In addition, the effect of operation temperature and feed sulfur content on membrane performance were also systematically investigated.

Photo-tearable tape close-wrapped upconversion nanocapsules for near-infrared modulated efficient siRNA delivery and therapy

RNA interference (RNAi) has become an appealing therapeutic approach for cancer and other diseases. One key challenge is the effective protection of these small fragile biomolecules against complicated physiological environments as well as efficient on-demand release. Here we design a photo-tearable polymer tape close-wrapped nanocapsule for efficient NIR modulated siRNA delivery. The photo-tearable nanocapsules comprise core-shell upconversion nanoparticles (UCNPs) coated with mesoporous silica layer for loading of photosensitizer hypocrellin A (HA) and small interfering RNA (siRNA) against polo-like kinase 1 (PLK1), and covalently bound thin membranes of polyethylene glycol (PEG) via a synthesized photocleavable linker (PhL). Upon irradiation at 980 nm, the UCNPs produce UV emissions to break PhL and tear out PEG membrane for siRNA release, and blue emissions to activate HA for generating reactive oxygen species (ROS). The close PEG membrane wrapping not only guarantees the efficient intracellular photocleavage, but also extends the circulation time and protects the loaded cargos from leakage and degradation. The ROS assists endosomal escape of the loaded cargos, therefore effectively improves the gene silencing efficiency and the suppressions of cell proliferation in vitro and tumor growth in vivo. The proposed photo-tearable tape-wrapped nanocapsules have promising potential application in precision medicine.

PEG/PVDF membranes for separating organosulphur compounds from n‐heptane: Effect of PEG molecular weight

Polyethylene glycol (PEG) of three different molecular weights was used to prepare PEG/PVDF composite membranes for separating organosulphur compounds from n‐heptane by pervaporation. All the composite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and positron annihilation spectroscopy (PAS). The effects of operating temperature, feed sulphur content, and organosulphur species on performance of PEG/PVDF composite membranes with different molecular weights were investigated. When the feed organosulphur was thiophene, the fluxes decreased with an increase in PEG molecular weight, however, the enrichment factors were in a different order: PEG membrane with molecular weight of 35 000 exhibited the highest enrichment factor of 12.59 for thiophene at 85 °C. When the feed organosulphur was 2‐methylthiophene or 2,5‐dimethylthiophene, it was found that the PEG membrane with molecular weight of 100 000 showed the highest enrichment factor. The results showed that PEG molecular weight has a considerable effect on separation performance for pervaporation desulphurization.

Maxillary Sinus Floor Augmentation Using Biphasic Calcium Phosphate and a Hydrogel Polyethylene Glycol Covering Membrane: An Histological and Histomorphometric Evaluation.

Maxillary sinus floor augmentation with a lateral approach is usually performed using a bone substitute covered with standard collagen or a synthetic barrier membrane to prevent soft tissue ingrowth within the bone graft. The purpose of this case series was to evaluate a polyethylene glycol (PEG) membrane with a hydrogel consistency, used to protect the lateral sinus anstrotomy, by analyzing the histological quality and histomorphometric quantity of newly formed bone (NB) in a maxillary sinus graft using biphasic calcium phosphate (BCP). Fifteen sinuses were grafted from 12 patients. Six months after the maxillary sinus floor augmentation, bone biopsies were harvested from 7 patients during the implant placement second-step surgery. The histomorphometric evaluation of the 7 grafted sinuses showed mean values of 27.4 ± 4.6% for NB, 26.9 ± 5.4% for remaining BCP particles, and 45.7 ± 6.0% for connective tissue/bone marrow. No implant failure was observed in the 14- to 45-month follow-up period after maxillary sinus floor augmentation procedure and in the 8- to 39-month follow-up period after implant loading. The use of a hydrogel PEG membrane to protect BCP proved to be a valuable grafting procedure to enhance the vital bone formation in the maxillary sinus floor augmentation procedure.

In Vivo Evaluation of Commercially Available Gel-Type Polyethylene Glycol Membrane for Carrier of Recombinant Human Bone Morphogenetic Protein-2

This study evaluated a commercially available, 3-dimensional gel-type polyethylene glycol (PEG) membrane as a carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2) using a rat calvarial defect model. Another gel-type carrier, fibrin-fibronectin system (FFS), was used as a positive control. Critical-size defects were made in the rat calvarium, which were allocated to 1 of 10 groups comprising 2 healing periods and biomaterial conditions: 1) sham control, 2) FFS only, 3) FFS plus BMP-2, 4) PEG only, and 5) PEG plus BMP-2. Radiographic and histologic analyses were performed at 2 and 8weeks after surgery. After 2weeks, some parts of the FFS were biodegraded and extensive cellular infiltration was observed at sites that received FFS or FFS plus BMP-2. The PEG membrane retained its augmented volume without cellular infiltration at sites that received PEG or PEG plus BMP-2. After 8weeks, the FFS was completely degraded and replaced by new bone and connective tissues. In contrast, the volume of residual PEG was similar to that at 2weeks, with slight cellular infiltration. In particular, there was progressive bone regeneration around micro-cracks and resorbed outer surface in the PEG+ BMP-2 group. Although the PEG+ BMP-2 group showed increased area and percentage of new bone, there was no statistical relevance after 2 and 8weeks in histomorphometric analyses. However, the appearance of the healing differed (with new bone formation along micro-cracks in the PEG+ BMP-2 group), and further studies with longer healing periods are needed to draw conclusions about clinical applications. Evidence of mechanical stability and new bone formation along micro-cracks when using PEG plus BMP-2 might support the PEG membrane as a candidate carrier material for rhBMP-2.

PVDF MEMBRANE FOR OIL-IN-WATER SEPARATION VIA CROSS-FLOW ULTRAFILTRATION PROCESS

The objective of this study is to investigate the potential of ultrafiltration polyvinylidene fluoride (PVDF)-titanium dioxide (TiO2) membrane for oil-in-water separator. PVDF polymeric matrix membrane is excellent in term of chemical and thermal stabilities, which make it very promising to be used as a membrane matrix for water separation. However, poor hydrophilic property of the PVDF has led to the severe fouling during operation. Thus, current work was performed to investigate the effect of incorporation of two additives i.e. polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) in PVDF-TiO2 membrane, which fabricated using dry/wet phase inversion technique. Membranes characterizations were performed using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle and UV-vis spectrophotometer. Accordingly, modified PVDF membrane possessed good hydrophilicity property when the additives were added into PVDF-TiO2 membrane matrix. In term of filtration performance, the experimental results showed that oil rejection using PVDF-TiO2/PVP membrane were ~99.7%, which met the requirement for discharge. On the other hand, PVDF-TiO2/PEG membrane was shown more enhancement in terms of permeate flux by given over 64 (L/m2h) at pressure of 2 bar gauge.

Novel proton conducting polymer electrolyte and its application in microbial fuel cell

The present work aimed the realization of plasticized polymer electrolyte membrane (PEM) which comprises of polyvinyl alcohol (PVA), sulfamic acid (SA) and polyethylene glycol (PEG) as a separator for the replacement of nafion membranes used in a microbial fuel cell (MFC). PEG was used as plasticizer. Electrical conductivity studies were carried out to investigate the suitability of the polymer electrolytes as a separator for MFC. The highest conductivity was calculated as 1.32×10−6Scm−1 for the plasticized polymer electrolyte membrane at 303K. Investigations were made to analyze the efficacy of PVA–SA–PEG membranes as separator for MFC. The performance of MFC with PVA–SA–PEG separator was analyzed by polarization studies, COD (Chemical Oxygen Demand) removal rate and coulombic efficiency. MFC's with nafion membrane as separator was used as the reference. The power output of MFC with PVA–SA–PEG separator was found to be comparable with the power yield of MFC with nafion separator. The PVA–SA–PEG membrane was identified as a promising separator for MFC applications due to its performance in terms of yield besides decreasing the cost of installation.

Integration of Peptides for Enhanced Uptake of PEGylayed Gold Nanoparticles.

Polyethylene glycol (PEG) has promoted the prospective applications of nanoparticles (NPs) in cancer therapy. PEG is used to evade the immune system allowing NPs accumulation within the tumor using its leaky vasculature. However, the cellular uptake of PEG-coated (PEGylated) NPs is lower in comparison to non-PEGylated NPs since PEG minimizes surface binding of ligands that mediate NP endocytosis. For improved outcome in therapeutic applications, it is necessary to enhance the uptake of PEGylated NPs. We added a peptide containing an integrin binding domain known as the RGD sequence to the NP surface in addition to PEG. We used gold NPs (GNPs) of sizes 14, 50, and 70 nm in this study. Our in vitro data for HeLa cells show enhanced uptake for NPs coated with both PEG and the peptide in comparison to PEGylated GNPs. NPs of size 50 nm had the highest uptake among the three sizes for all GNP surfaces. A similar size-dependent trend was observed for MDA-MB-231 cells for as-made GNPs with lower uptake in comparison to HeLa cells. However, only 14 nm peptide-modified PEGylated NPs had enhanced uptake. Hence, NP uptake was found dependent on cell type and NP surface properties. A properly designed NP system with both PEG and cell membrane targeting peptides can be used to protect it from the immune system and promote internalization by cells upon entry into tumor environment.

Nano composite PEBAX®/PEG membranes: Effect of MWNT filler on CO2/CH4 separation

The performances of two-phase polymer-liquid PEBAX®/polyethylene glycol (PEG) and three-phase polymer-liquid-solid PEBAX®/PEG/MWNT thin film composite membranes for CO2 and CH4 permeation were studied. The effect of temperature and MWNT/PEBAX® ratio on single gas (CO2 and CH4) permeability was investigated. The permeation of both gases was measured at different temperatures from 303 to 323 ˚K. The results exhibited that the PEBAX®/PEG/MWNT membrane had better permeability for CO2 in comparison to the PEBAX®/PEG membrane, whereas CO2/CH4 selectivities in both membranes were almost the same; i.e. MWNT filler promoted the performance of PEBAX®/PEG membrane in CO2/CH4 Separation. Also, the permeability increases with temperature in all experiments. For the three-phase PEBAX®/PEG/MWNT membrane, CO2 permeability was determined 221 Barrer in 323˚K and the selectivity was obtained as 23 in 303 ˚K.

Chemically- and mechanically-tunable porated polyethylene glycol gels for leukocyte integrin independent and dependent chemotaxis

The extracellular matrix (ECM) is a highly complex mixture of protein, proteoglycans and growth factors that biochemically and mechanically regulates leukocyte migration during inflammation. Perturbations in ECM composition and mechanical properties are associated with the pathogenesis of chronic inflammatory diseases ranging from asthma to diabetes. The limited availability of in vitro models of human ECM has impeded inflammatory research, as current methods rely heavily on polycarbonate transwells and glass coverslips, which cannot accurately replicate the combined mechanical and biochemical properties of human ECM. Polyethylene glycol (PEG) hydrogels offer a highly tunable substrate, with respect to both mechanical properties (as a function of molecular weight) and protein conjugation; unmodified PEG, however, cannot be used for leukocyte migration studies due to its impenetrable pore networks. We present a modifi ed PEG membrane in which hydrogel pore size, pore density, mechanical stiffness, and protein presentation can be easily controlled to mimic various human ECM, providing a new technology for investigating leukocyte recruitment.

Effect of Polyethylene Glycol Membrane on the Separation of Biodiesel from Palm Oil

Effect of Polyethylene Glycol Membrane on the Separation of Biodiesel from Palm Oil