Polyethylene Glycol Polymers Research Articles

Development and Evaluation of Flupirtine Maleate Transdermal Patch Containing Different Permeation Enhancers

The present study was aimed at the formulation of transdermal patches of flupirtine maleate containing different permeation enhancers. It acts indirectly as N-methyl-D-aspartate (NMDA) receptor antagonist and activates the K+ channels; thereby acts as a skeletal muscle relaxant. Flupirtine maleate transdermal patches are intended to provide localized effect. The patches were prepared by solvent evaporation technique, using polyvinyl alcohol (PVA) as the polymer whereas dimethyl sulfoxide (DMSO) and polyethylene glycol (PEG-400) as the permeation enhancers. Methanol was used as a solvent to dissolve the drug and glycerol was used as the plasticizer. These patches were evaluated for in vitro permeation, tensile strength, percent moisture absorption, drug content uniformity, film thickness, weight variation and folding endurance. All the patches showed extended release properties. Formulation FDD8 containing 8% polymer and 2% DMSO was found to be the optimized formulation on the basis of evaluation parameters. In vitro permeation release was found to be 95.71 ± 0.01% at the end of 12 h. As the concentration of DMSO increased, the release profile of drug was enhanced. This indicated that DMSO improved the release profile of flupirtine maleate when compared to PEG-400. The release kinetics of the transdermal patches followed Higuchi matrix model. The stability studies showed that all the optimized patches were stable during their study period. From the present study, it can be concluded that addition of DMSO yields good result to enhance the permeation of the drug. Keywords: flupirtine maleate, transdermal patch, permeation enhancers, dimethyl sulfoxide DMSO, polyethylene glycol PEG-400, polyvinyl alcohol PVA.

Natural Presentation of Glycosaminoglycans in Synthetic Matrices for 3D Angiogenesis Models.

Glycosaminoglycans (GAGs) are long, linear polysaccharides that occur in the extracellular matrix of higher organisms and are either covalently attached to protein cores, as proteoglycans or in free form. Dependent on their chemical composition and structure, GAGs orchestrate a wide range of essential functions in tissue homeostasis. Accordingly, GAG-based biomaterials play a major role in tissue engineering. Current biomaterials exploit crosslinks between chemically modified GAG chains. Due to modifications along the GAG chains, they are limited in their GAG-protein interactions and accessibility to dissect the biochemical and biophysical properties that govern GAG functions. Herein, a natural presentation of GAGs is achieved by a terminal immobilization of GAGs to a polyethylene glycol (PEG) hydrogel. A physicochemical characterization showed that different end-thiolated GAGs can be incorporated within physiological concentration ranges, while the mechanical properties of the hydrogel are exclusively tunable by the PEG polymer concentration. The functional utility of this approach was illustrated in a 3D cell culture application. Immobilization of end-thiolated hyaluronan enhanced the formation of capillary-like sprouts originating from embedded endothelial cell spheroids. Taken together, the presented PEG/GAG hydrogels create a native microenvironment with fine-tunable mechanobiochemical properties and are an effective tool for studying and employing the bioactivity of GAGs.

Comparison of pharmacokinetics and biodistribution of laser-synthesized plasmonic Au and TiN nanoparticles

Plasmonic nanostructures offer wide range of diagnostic and therapeutic functionalities for biomedical applications. Gold nanoparticles (Au NPs) present one of the most explored nanomaterial in this field, while titanium nitride nanoparticles (TiN NPs) is a new promising nanomaterial with superior plasmonic properties for biomedicine. However conventional chemical techniques for the synthesis of these nanomaterials cannot always match stringent requirements for toxicity levels and surface conditioning. Laser-synthesized Au and TiN NPs offer exceptional purity (no contamination by by-products or ligands) and unusual surface chemistry. Therefore, these NPs present a viable alternative to chemically synthesized counterparts. This work presents comparative analysis of pharmacokinetics and biodistribution of laser-synthesized 20 nm Au and TiN NPs under intravenous administration in mice model. Our data show that Au NPs and bare TiN NPs are rapidly eliminated from the blood circulation and accumulate preferentially in liver and spleen, while coating of TiN NPs by hydrophilic polymer polyethylene glycol (PEG) significantly prolongates blood circulation time and improves delivery of the NPs to tumor. We finally discuss potential applications of laser synthesized Au NPs in SERS, SEIRA and electrocatalysis, while TiN nanoparticles are considered as promising agents for photothermal therapy and photoacoustic imaging.

Enzymatically releasable polyethylene glycol – host defense peptide conjugates with improved activity and biocompatibility

Host defense peptides (HDPs) have been the subject of great interest for the treatment of multidrug-resistant bacterial infections due to their multimodal activity and low induction of resistance. However, aggregation, toxicity, and short biological half-life have limited their applicability for clinical treatment. Many methods have been explored to alleviate these issues, such as polymer (e.g., polyethylene glycol (PEG)) conjugation, but these are often accompanied by reductions in the activity of the HDP. Here, we detail the design of a novel PEG-HDP conjugate incorporating an enzymatic cleavage sequence targeting matrix metalloproteinases (MMPs) that accumulate at sites of inflammation and infection. Addition of the cleavage sequence onto either the N- or the C-terminal region of the parent peptide (peptide 73, a derivative of the HDP aurein 2.2) was explored to determine the location for optimal antimicrobial activity following MMP cleavage; furthermore, the susceptibility of the peptide to MMP cleavage after conjugation to 2 kDa or 5 kDa PEG was examined. The top candidate, L73, utilized an N-terminal cleavage site that was subsequently conjugated to a 2 kDa PEG polymer. Both L73 and the conjugate exhibited no antimicrobial activity in vitro until cleaved by purified MMP, which liberated a peptide fragment with 16- or 63-fold improved activity, respectively, corresponding to a minimum inhibitory concentration (MIC) of 8 μg/mL, comparable to that of peptide 73 (4 μg/mL). Furthermore, PEG conjugation improved the blood compatibility and reduced the aggregation tendency of the HDP in vitro, indicating enhanced biocompatibility. When administered as a single subcutaneous dose (~3.6 mg, or a peptide concentration of 142 mg/kg) in a mouse abscess model of high-density methicillin-resistant Staphylococcus aureus (MRSA) infection, the conjugate displayed strong activity, reducing abscess size and bacterial load by 73.3% and 58-fold, respectively. This activity was completely lost when the cleavage site was rendered resistant to MMPs by the substitution of two d-amino acids, supporting the hypothesis that antimicrobial activity was dependent on cleavage by MMPs, which were shown here to increasingly accumulate at the abscess site up to 18 h post infection. Finally, the conjugate displayed biocompatibility in vivo, with no identifiable toxicity or aggregation.

Detecting glycated hemoglobin in human blood samples using a transistor-based nanoelectronic aptasensor

Glycated hemoglobin A1c (HbA1c) is a measure of long-term glycemic control in chronic diabetes-related complications. In this study, the glycated N-terminus of the hemoglobin β-chain, i.e., the glycated peptide (GP) of Fru-Val-His-Leu-Thr-Pro-Glu-COOH, was used as a template to isolate a novel aptamer (denoted by AptGP) via the systematic evolution of ligands by the exponential enrichment (SELEX) technique. Molecular docking/simulation studies revealed that both H-bonding and nonbonded interactions dominate the GP-AptGP association. While the fructose group of GP binds to the hairpin region of AptGP, the peptide chain aligns with the groove surface of AptGP. This AptGP was then modified on a silicon nanowire field-effect transistor (AptGP/SiNW-FET) to recognize HbA1c in physiological solutions. To mitigate the Debye-Hückel screening effect, a porous and HbA1c-permeable polyethylene glycol (PEG) polymer was comodified on the AptGP/SiNW-FET surface (termed PEG:AptGP/SiNW-FET) to enable the detection of HbA1c in peripheral human blood. The binding free energy (−12.30 ± 0.05 kcal/mol) of the GP-AptGP complex determined experimentally by PEG:AptGP/SiNW-FET matches excellently with theoretical calculations. This reusable PEG:AptGP/SiNW-FET aptasensor detects HbA1c levels in human blood as accurately as conventional capillary electrophoresis but has the advantages of being fast and cost-effective and thus is amenable to point-of-care diagnostics.

Evaluation of Microfluidic Approaches to Encapsulate Cells into PEGDA Microparticles

PurposePolyethylene glycol diacrylate (PEGDA) is increasingly used to microencapsulate cells via a vortex-induced water-in-oil emulsion process. Herein, we evaluated methods to encapsulate cells into microparticles using microfluidic methods.MethodsPEGDA prepolymer solution with or without cells was photopolymerized with white light under varying microfluidic parameters to form empty microspheres or cell-laden microparticles. Microparticles and entrapped cells were assessed for size and viability.ResultsPEGDA microparticles were easily formed when cells were absent; the introduction of cells resulted in aggregation that clogged microfluidic devices, resulting in a mix of empty polymer microparticles and cells that were not encapsulated. Cells that were successfully encapsulated had poor viability.ConclusionMicrofluidic methods may work for low density microencapsulation of mammalian cells; however, when the cell density within each microparticle must be relatively high, emulsion-based methods are superior to microfluidic methods.Lay SummaryThe synthetic polymer polyethylene glycol diacrylate (PEGDA) has been increasingly used to encapsulate cells into micrometer-sized hydrogel spheres (microspheres). One method to microencapsulate cells has been to form a water-in-oil emulsion with liquid polymer containing cells and then expose the suspended droplets to white light, polymerizing them into PEGDA hydrogel microspheres. Although successful, this method has poor control over the process, resulting in polydisperse microsphere sizes with varying cell density. We evaluated microfluidic methods to form both empty and cell-laden PEGDA microspheres. Although microfluidic methods resulted in monodisperse microsphere sizes, the introduction of cells resulted in clogging of microfluidic devices, non-spherical microparticles, and poor cell viability.Future WorkBecause the microfluidic approach successfully formed cell-free microspheres, the effect of reducing cell aggregation will be examined. Specifically, the use of anti-aggregation agents as well as a reduced cell density in the liquid polymer phase and their effects on polymer formation will be explored.

A green MXene-based organohydrogel with tunable mechanics and freezing tolerance for wearable strain sensors

Conductive hydrogels have attracted considerable attention owing to their potential for use as electronic skin and sensors. However, the loss of the inherent elasticity or conductivity in cold environments severely limits their working conditions. Generally, organic solvents or inorganic salts can be incorporated into hydrogels as cryoprotectants. However, their toxicity and/or corrosive nature as well as the significant water loss during the solvent exchange present serious difficulties. Herein, a liquid-like yet non-toxic polymer-polyethylene glycol (PEG) was attempted as one of the components of solvent for hydrogels. In the premixed PEG-water hybrid solvent, polyacrylamide (PAAm) was in situ polymerized, overcoming the inevitable water loss induced by the high osmotic pressure of the PEG solution and achieving tailored water capacity. Interestingly, the mechanical strength (“soft-to-rigid” transition) and anti-freezing properties of organohydrogels can be simultaneously tuned over a very wide range through adjusting PEG content. This was due to that with increasing PEG in solvent, the PAAm chains transformed from stretching to curling conformation, while PEG bonded with water molecules via hydrogen bonds, weakening the crystallization of water at subzero temperature. Additionally, a highly conductive Ti3C2Tx-MXene was further introduced into the organohydrogels, achieving a uniform distribution triggered by the attractive interaction between the rich functional groups of the nanofillers and the polymer chains. The nanocomposite hydrogels demonstrate high electrical conductivity and strain sensitivity, along with a wide working temperature window. Such a material can be used for monitoring human joint movement even at low temperature and has potential applications in wearable strain sensors.

From Attraction to Repulsion to Attraction: Non-monotonic Temperature Dependence of Polymer-Mediated Interactions in Colloidal Dispersions.

In this work, we have synthesized polystyrene particles that carry short end-grafted polyethylene glycol (PEG) chains. We then added dissolved 100 kDa PEG polymers and monitored potential flocculation by confocal microscopy. Qualitative predictions, based on previous theoretical developments in this field (Xie, F.; et al. Soft Matter 2016, 12, 658), suggest a non-monotonic temperature response. These theories propose that the "free" (dissolved) polymers will mediate attractive depletion interactions at room temperature, with a concomitant clustering/flocculation at a sufficiently high polymer concentration. At high temperatures, where the solvent is poorer, this is predicted to be replaced by attractive bridging interactions, again resulting in particle condensation. Interestingly enough, our theoretical framework, based on classical density functional theory, predicts an intermediate temperature regime where the polymer-mediated interactions are repulsive! This obviously implies a homogeneous dispersion in this regime. These qualitative predictions have been experimentally tested and confirmed in this work, where flocs of particles start to form at room temperature for a high enough polymer dosage. At temperatures near 45 °C, the flocs redisperse, and we obtain a homogeneous sample. However, samples at about 75 °C will again display clusters and eventually phase separation. Using results from these studies, we have been able to fine-tune parameters of our coarse-grained theoretical model, resulting in predictions of temperature-dependent stability that display semiquantitative accuracy. A crucial aspect is that under "intermediate" conditions, where the polymers neither adsorb nor desorb at the particle surfaces, the polymer-mediated equilibrium interaction is repulsive.

A Scalable Graph Neural Network Method for Developing an Accurate Force Field of Large Flexible Organic Molecules

An accurate force field is the key to the success of all molecular mechanics simulations on organic polymers and biomolecules. Accurate correlated wave function (CW) methods scale poorly with system size, so this poses a great challenge to the development of an extendible ab initio force field for large flexible organic molecules at the CW level of accuracy. In this work, we combine the physics-driven nonbonding potential with a data-driven subgraph neural network bonding model (named sGNN). Tests on polyethylene glycol, polyethene, and their block polymers show that our strategy is highly accurate and robust for molecules of different sizes and chemical compositions. Therefore, one can develop a parameter library of small molecular fragments (with sizes easily accessible to CW methods) and assemble them to predict the energy of large polymers, thus opening a new path to next-generation organic force fields.

Water-in-Water Emulsions, Ultralow Interfacial Tension, and Biolubrication

Water-in-Water Emulsions, Ultralow Interfacial Tension, and Biolubrication

Facile and green fabrication of flame-retardant Ti3C2Tx MXene networks for ultrafast, reusable and weather-resistant fire warning

Fire warning sensor capable of rapidly monitoring critical fire risk of combustible materials growingly plays a crucial role in reducing or avioding fire disaster under complicated environments. Unfortunately, to date the rational design of smart fire warning sensors that are reusable and weather-resistant remains a major challenge. Here, we report a facile and green strategy for fabricating biomimetic polyethylene glycol or polyvinyl pyrrolidone polymer decorated Ti3C2Tx MXene networks that possess exceptional flame resistance and sensitive fire cyclic warning performance. Novel fire warning sensors that were constructed based on the as-prepared inherently fire-retardant MXene networks exhibit ultrafast fire warning response and recovery time (~1.8 s and ~1.0 s), resistance switching behavior with >4 orders of magnitude, and stable fire cyclic warning capability for 100 cycles. Structural observation and analysis disclose that, upon flame attack, thermal pyrolysis of the polymer molecules facilitates the oxidation of MXene sheets to form a compact fish scale-like C/N dopped titania network, and meanwhile its electron excitation is thus activated to generate a sensitive resistance transition to trigger a rapid fire cyclic warning signal. More improtantly, the multifunctional MXene networks treated with silane modification not only endow combustible substrate with excellent super-hydrophobicity and outstanding flame resistance, but provide reusable and weather-resistant fire warning responses even after one-year outdoor exposure. Therefore, this work provides an innovative concept of advanced MXene composites and design of fire cyclic warning sensors for fire safety and prevention.

The Effect of Additional Polyethylene Glycol (PEG) as Coating Fe3O4 for Magnetic Nanofluid Applications

Background & Objective: Magnetic nanofluid is a special class of nanofluid that exhibits both magnetic and fluid properties. The main purpose of using magnetic nanofluid as a heat transfer medium is the possibility of controlling the flow and the heat transfer process through an external magnetic field. This research aims at identifying the effect of adding polyethylene glycol (PEG) to magnetite (Fe3O4) nanoparticles for magnetic nanofluid applications. Method: The nanofluid was prepared by synthesizing Fe3O4 nanoparticles using the chemical precipitation method and then dispersing them in distilled water using a sonicator. Results: The result of XRD is that nanoparticles had inverse spinel structures, and the smallest crystallite size is found in the Fe3O4@PEG-6000 samples. FE-SEM and TEM show that the addition of PEG can reduce the Fe3O4 agglomeration, and the smallest particle size is found in the Fe3O4@PEG-6000 samples. The result of FT-IR shows that there is a surface modification of Fe3O4 nanoparticles and PEG polymer. The result of VSM shows the coercivity value is small; hence, the sample is a superparamagnetic material. The addition of PEG increases the thermal conductivity of Fe3O4 nanoparticles. Conclusion: The addition of PEG makes particle size smaller, reduce the agglomeration and increases the thermal conductivity, so that it is potential for magnetic nanofluid applications.

PLGA-CS-PEG Microparticles for Controlled Drug Delivery in the Treatment of Triple Negative Breast Cancer Cells

In this study, we explore the development of controlled PLGA-CS-PEG microspheres, which are used to encapsulate model anticancer drugs (prodigiosin (PGS) or paclitaxel (PTX)) for controlled breast cancer treatment. The PLGA microspheres are blended with hydrophilic polymers (chitosan and polyethylene glycol) in the presence of polyvinyl alcohol (PVA) that were synthesized via a water-oil-water (W/O/W) solvent evaporation technique. Chitosan (CS) and polyethylene glycol (PEG) were used as surface-modifying additives to improve the biocompatibility and reduce the adsorption of plasma proteins onto the microsphere surfaces. These PLGA-CS-PEG microspheres are loaded with varying concentrations (5 and 8 mg/mL) of PGS or PTX, respectively. Scanning electron microscopy (SEM) revealed the morphological properties while Fourier transform infrared spectroscopy (FTIR) was used to elucidate the functional groups of drug-loaded PLGA-CS-PEG microparticles. A thirty-day, in vitro, encapsulated drug (PGS or PTX) release was carried out at 37 °C, which corresponds to human body temperature, and at 41 °C and 44 °C, which correspond to hyperthermic temperatures. The thermodynamics and kinetics of in vitro drug release were also elucidated using a combination of mathematical models and the experimental results. The exponents of the Korsmeyer–Peppas model showed that the kinetics of drug release was well characterized by anomalous non-Fickian drug release. Endothermic and nonspontaneous processes are also associated with the thermodynamics of drug release. Finally, the controlled in vitro release of cancer drugs (PGS and PTX) is shown to decrease the viability of MDA-MB-231 cells. The implications of the results are discussed for the development of drug-encapsulated PLGA-CS-PEG microparticles for the controlled release of cancer drugs in treatment of triple negative breast cancer.

Enhanced bone tissue regeneration via bioactive electrospun fibrous composite coated titanium orthopedic implant

One of the very reliable, attractive, and cheapest techniques for synthesizing nanofibers for biomedical applications is electrospinning. Here, we have created a novel nanofibrous composite coated Ti plate to mimic an Extra Cellular Matrix (ECM) of native bone in order to enhance the bone tissue regeneration. An electrospun fibrous composite was obtained by the combination of minerals (Zn, Mg, Si) substituted hydroxyapatite (MHAP)/Polyethylene Glycol (PEG)/Cissus quadrangularis (CQ) extract. Fibrous composite’s functionality, phase characteristics, and morphology were evaluated by FT-IR, XRD, and SEM techniques, respectively. The average fiber diameter of MHAP/PVA had decreased from ~274 to ~255 nm after incorporating PEG polymer. That further increased from ~255 to ~275 nm after adding CQ extract. Besides the bioactivity in SBF solution, the degradable nature was confirmed by immersing the fibrous composite in Tris-HCL solution. The degradable studies evaluate that the composite was degraded depending on time, and it degrades about 9.42% after 7 days of immersion. Osteoblasts like MG-63 cells differentiation, proliferation, and calcium deposition were also determined. These results show that this new fibrous composite exhibits advanced osteoblasts properties. Thus, we concluded that this new fibrous scaffold coated Ti implant could act as a better implant to mimic ECM of bone structure and to improve osteogenesis during bone regeneration.

Computational design of a minimal “protein-like” conjugate for potent membrane poration

Biomimetic membrane nanopores have great potentials for bio- and nanotechnology applications. Here, a design strategy of an artificial protein by reasonably conjugating peptides and polymers for membrane poration was developed based on the α-helical bundle framework. A serial of peptide-polymer conjugates, composed of the α-helical peptide melittin (Mel) and clinically available polymer polyethylene glycol, were fabricated. Within them, the S-Mel, consisting of four helices arranged in a star-like bundle structure, demonstrated the most improved performance. Specifically, one single S-Mel molecule can build a stable membrane pore. Moreover, the obtained pores display stimuli-responsive properties in both size (including water flux) and structure, which is ascribed to the molecular architecture-regulated helical packing changes of S-Mel during membrane actions. These results promise S-Mel the ability to achieve ONOFF switching and gating effects for selective mass translocation across a cell membrane and help understand the structure-function relationship of proteins.

Thermal stability and plasmonic photothermal conversion of surface-modified solar nanofluids: Comparing prolonged and cyclic thermal treatments

In this work, the thermal stability of plasmonic nanofluids upon continuous and cyclic heating and cooling for different durations and temperatures was investigated for volumetric-absorption solar applications. Gold nanoparticles (AuNPs) capped with citrate (CIT) were compared to polymer-protected AuNPs coated using physical/chemical adsorption with natural bovine serum albumin (BSA) or synthetic polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) polymers. Evaluation of post-test stability and identification of possible failure modes were realized using complementary characterization techniques. Furthermore, simulations were used to gain insight on the effects of nanofluid stability on the optical and thermal performance of direct-absorption solar collectors (DASCs). All nanofluid types retained their dispersion stability after long-term aging for 3 + years. For the first time, to our knowledge, the heating mode (whether cyclic or continuous), not just the heating temperature and duration, was found to play a critical role in determining the effects on dispersion stability, physicochemical coating transformations, optical properties, and wettability of nanofluids. This emphasized the importance of testing solar nanofluids using thermal stability tests that mimicked the cumulative failure modes induced by diurnal solar cycling. The impact of prolonged and cyclic heating was found to vary from excessive aggregation, weakened polymer-Au linkage, and reduced polymer–solvent affinity, depending on the AuNP coating. Overall, PVP was found most suitable as a soft protectant shell for plasmonic nanoparticles in solar photothermal applications. This work represents an important step towards the commercial use of photothermally efficient yet colloidally stable solar nanofluids capable of retaining their superior properties in field deployments.

Paramagnetic block copolymers: An effective tool for targeted radiography of rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by erosive arthritis. Accurate diagnosis of RA mostly depends on the quality of magnetic resonance imaging (MRI). To obtain stable and clear imaging signals, it is necessary to design and develop a superstable and highly sensitive contrast agent. This study synthesized a diblock polymer polyethylene glycol–tert-butyl polyacrylate (PEG-b-PAA) by in situ polyol polymerization, coated it with ultrasmall paramagnetic iron oxide (USPIO), and conjugated folic acid to the PEG-b-PAA/USPIO surface to impart targeting function. The addition of USPIO effectively enhanced MRI quality in delayed T2-weighted images (T2WI), as observed through synovial signal changes other than morphological changes, early monitoring RA lesions, and drug treatment response. Enhanced T2WI helped evaluate the characteristics of synovial perfusion, which further confirmed the feasibility of MRI using FA-PEG-b-PAA/USPIO. These results showed that FA-PEG-b-PAA/USPIO has great potential in the clinical application of MRI for RA diagnosis.

The histopathological effects of reabsorbable polyethylene glycol hydrogel (Coseal) on epidural fibrosis in an experimental postlaminectomy model in rats

Background/aimTo investigate the histopathological effects of reabsorbable polyethylene glycol hydrogel (RPGH, Coseal) on epidural fibrosis (EF) following laminectomy in rats.Materials and methodsA total of 24 rats were equally divided into three groups. In the first group, no treatment was applied after laminectomy (control group, Group 1). In the second group, hemostasis was achieved after laminectomy, and 2 mm absorbable gelatin sponge soaked in saline was placed over the epidural space and the wound was closed (Group 2). In the third group, hemostasis was achieved following laminectomy, and 0.5 mL RPGH (Coseal, Group 3) was squeezed over the dura mater, and the wound was closed. A histopathological examination was undertaken to evaluate arachnoidal invasion and EF.ResultsThe results of EF in the Group 2 and Group 3 were significantly lower compared to the Group 1 (p = 0.023 and p = 0.002, respectively). No statistically significant difference was found between the Group 2 and Group 3 in terms of EF (p = 0.957). There was also no statistically significant difference between the mean arachnoidal invasion of the three groups (p > 0.171). However, the rate of arachnoidal invasion was the lowest in the Group 3.ConclusionIntraoperative Coseal, a polyethylene glycol polymer, tends to reduce the risk of epidural fibrosis, although this is not statistically significant.

θ-Solvent-Mediated Double-Shell Polyethylene Glycol Brushes on Nanoparticles for Improved Stealth Properties and Delivery Efficiency.

Antifouling polymer brushes are widely used to inhibit the formation of protein corona on nanoparticles (NPs) and subsequent accumulation in the liver and spleen. Herein, we demonstrate a θ-solvent-mediated method for the preparation of gold nanoparticles with a high polyethylene glycol (PEG) grafting density. Reaching the θ-solvent by adding salt (e.g., Na2SO4) can significantly increase the grafting density of the PEG brush to 2.08 chains/nm2. The PEG polymer brush prepared in the θ-solvent possesses a double-shell structure consisting of a concentrated polymer brush (CPB) and a semidilute polymer brush (SDPB), denoted as NP@CPB@SDPB, while those prepared in a good solvent have only a SDPB shell, i.e., NP@SDPB. Compared to the NP@SDPB structure, the NP@CPB@SDPB structure decreases the liver accumulation from 34.0%ID/g to 23.1%ID/g, leading to an increase in tumor accumulation from 8.5%ID/g to 12.8%ID/g. This work provides new insights from the perspective of polymer physical chemistry into the improved stealth properties and delivery efficiency of NPs, which will accelerate the clinical translation of nanomedicine.

Furacin: More than just contact dermatitis from nitrofurazone

Furacin is an ointment for topical administration containing the antibiotic nitrofurazone (0.2%) and a mixture of polyethylene glycol (PEG) polymers (PEG 300, PEG 1500, PEG 4000) that act as a vehicle to facilitate its penetration through the skin.