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Current ionic polymer–metal composite (IPMC) actuators have severe actuation drawbacks (i.e. low force output and poor stability), hampering their applications. To address these issues, poly(ethylene glycol)‐grafted graphene oxide (PEG‐GO) is synthesized and incorporated into a Nafion matrix, thus producing a PEG‐GO hybrid Nafion film with better physiochemical properties for fabricating a high‐performance, low‐cost IPMC actuator. The modification of PEG to GO not only prevents GO agglomeration and sedimentation, but also avoids loss of PEG in water. Driven by a 0.2 Hz, 2.5 V electric field, the hybrid IPMC actuator exhibits superior electromechanical behaviors, i.e. a swing angle of 110.3°, a blocking force of 6.89 mN and a stable working time of 485 s, respectively increasing by 92%, 209% and 294% when compared to a pure Nafion actuator. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Stiffness‐variable polymers have found their enormous potential in practical applications that require automatic adaptation and modulation. However, prevailing materials are often constrained by specific operational triggers, limited mechanical responsiveness, and inadequate universality. In this study, drawing inspiration from the mechanism of non‐solvent induced phase separation (NIPS), a novel series of polymers exhibiting reversible water‐triggered stiffening is designed and synthesized by covalently incorporating poly(ethylene glycol) (PEG) as a non‐solvent mediator onto the hydrophobic poly(meth)acrylates backbones. Owing to the hydrophilicity difference between PEG sidechains and backbones, these polymers display swift and substantial alterations in stiffness, with large‐scale and regulable changes (from several‐fold to exceeding 200‐fold) upon water penetration, resulting from water‐induced microphase separation. Meanwhile, the polymers also possess intrinsic dual‐responsive shape‐memory properties. Due to the excellent commercial availability, versatility, and designability of these polymers, the work provides novel perspectives for the advancement of water‐triggered stiffening materials and opens avenues for their prospective applications in various domains. [ABSTRACT FROM AUTHOR]

The carbon dioxide (CO2) separation technology has become a focus recently, and a developed example is the membrane technology. It is an alternative form of enhanced gas separation performance above the Robeson upper bound line resulting in the idea of mixed matrix membranes (MMMs). With attention given to membrane technologies, the MMMs were fabricated to have the most desirable gas separation performance. In this work, blend MMMs were synthesised by using two polymers, namely, poly(ether sulfone) (PES) and poly (ethylene glycol) (PEG). These polymers were dissolved in blend N-methyl-2-pyrrolidone (NMP) and dimethylformamide (DMF) solvents with the functionalised multi-walled carbon nanotubes (MWCNTs-F) fillers by using the mixing solution method. The embedding of the pristine MWCNTs and MWCNTs-F within the new synthesised MMM was then studied towards CO2/N2 separation. In addition, the optimisation of the loading of MWCNTs-F for blend MMM for CO2/N2 separation was also studied. The experimental results showed that the functionalised MWCNTs (MWCNTs-F) were a better choice at enhancing gas separation compared to the pristine MWCNTs (MWCNTs-P). Additionally, the effects of MWCNTs-F at loadings 0.01 to 0.05% were studied along with the polymer compositions for PES:PEG of 10:20, 20:20 and 30:10. Both these parameters of study affect the manner of gas separation performance in the blend MMMs. Overall, the best performing membrane showed a selectivity value of 1.01 + 0.05 for a blend MMM (MMM-0.03F) fabricated with 20 wt% of PES, 20 wt% of PEG and 0.03 wt% of MWCNTs-F. The MMM-0.03F was able to withstand a pressure of 2 bar, illustrating its mechanical strength and ability to be used in the post combustion carbon capture application industries where the flue gas pressure is at 1.01 bar. [ABSTRACT FROM AUTHOR]

In this study, bionanocomposite films based on poly(lactide) (PLA) plasticised with poly(ethylene glycol) (PEG) (7.5 wt%) and reinforced with various contents of nanofibrillated cellulose (NFC) (1, 3, 5 wt%) were prepared. The hydrothermal degradation was investigated through immersion in several aqueous environments at temperatures of 8, 23, 58, and 70 °C as a function of time (7, 15, 30, 60, 90 days). The effect of water immersion on the physicochemical properties of the materials was assessed by monitoring the changes in the morphology, thermo-oxidative stability, thermal properties, and molar mass through field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The hydrothermal degradation behaviour was not critically affected regardless of the nanofibrillated cellulose content. All the materials revealed certain integrity towards water immersion and hydrolysis effects at low temperatures (8 and 23 °C). The low hydrothermal degradation may be an advantage for using these PLA biocomposites in contact with water at ambient temperatures and limited exposure times. On the other hand, immersion in water at higher temperatures above the glass transition (58 and 70 °C), leads to a drastic deterioration of the properties of these PLA-based materials, in particular to the reduction of the molar mass and the disintegration into small pieces. This hydrothermal degradation behaviour can be considered a feasible option for the waste management of PLA/PEG/NFC bionanocomposites by deposition in hot aqueous environments. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) hydrogels have shown potential applications in bionic articular cartilage due to their tissue‐like viscoelasticity, good biocompatibility and low friction. However, their lack of adequate mechanical properties is a key obstacle for PVA hydrogels to replace natural cartilage. In this study, poly(ethylene glycol) (PEG) and glycerol were introduced into PVA, and a PVA/PEG–glycerol composite hydrogel was synthesized using a mixing physical crosslinking method. The mechanical properties, hydrophilicity and tribological behavior of the PVA/PEG–glycerol hydrogel were investigated by changing the concentration of glycerol in PEG. The results showed that the tensile strength of the hydrogel reached 26.6 MPa at 270% elongation at break with 20 wt% of glycerol plasticizer, which satisfied the demand of natural cartilage. In addition, the excellent hydrophilicity of glycerol provides good lubricating properties for the composite gel under dry friction. Meanwhile, self‐healing and cellular immunity assays demonstrated that the composite gel could have good self‐healing ability and excellent biocompatibility even in the absence of external stimuli. This study provides a new candidate material for the design of articular cartilage, which has the potential to facilitate advances in artificial joint cartilage repair. © 2022 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Amphiphilic copolymers with a main chain containing polyethylene glycol (PEG) and side chains of different molecular weight and hydrophobicity form spherical aggregates (micelles) in aqueous solution. The suitability of these for incorporation and delivery of small hydrophobic molecules depends strongly on their stability in solution and on their structural changes in contact with surfaces. Atomic force microscopy (AFM) in tapping mode in liquid was used to characterize adsorbed aggregates of a series of copolymers on a model hydrophilic surface (mica). Adsorbed aggregates did not retain the core-shell character they had in solution, but opened up completely to form a layer only 0.5−1 nm thick which corresponds to one or two cross-sectional diameters of individual PEG chains. A good correlation was found between the number of polymer chains in individual adsorbed aggregates as determined with AFM and that known from light scattering studies on the corresponding structures in solution, indicating that each aggregate on the surface originated from one aggregate in solution. Adsorption could be reduced with a more stable hydrophobic core and some copolymers did not adsorb on mica within the time studied. [ABSTRACT FROM AUTHOR]

Poly(lactic acid)-poly(ethylene glycol) with Boc-glycine linked copolymer was synthesized from lactic acid, poly(ethylene glycol), and Boc-glycine. The synthesized polymers were characterized by thermogravimetric analysis, differential scanning calorimetry, IR, and NMR spectroscopic techniques. Drug release, stability, and anti-inflammatory studies were conducted in vitro. This targeted polymer may be used in medical applications as a potential drug carrier. [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotubes (SWCNTs) have attracted great interest regarding drug-delivery applications. However, their application has been limited by some inherent disadvantages. In this study, raw SWCNTs were purified with different oxidizing acids, and the resulting shortened CNTs were conjugated with poly(ethylene glycol) (PEG) and polyethylenimine (PEI). The different nanocarriers, that is, CNTs-COOH (CNTs), CNTs-PEG and CNTs-PEG-PEI, were systematically characterized and evaluated in terms of drug loading, in vitro release, cytotoxicity towards MCF-7 cells and cellular uptake. The results showed that all CNT carriers had a high drug loading capacity. In comparison with CNTs-COOH and CNTs-PEG, CNTs-PEG-PEI showed a more rapid drug release under acidic conditions and a higher antitumor activity. Furthermore, fluorescence detection and flow cytometry (FCM) analysis results indicated that the internalization into cells of CNTs-PEG-PEI was significantly enhanced, thus inducing tumor cell death through apoptosis more efficiently. The above series of benefits of CNTs-PEG-PEI may be attributed to their good dispersibility and comparably higher affinity to tumor cells due to the difunctionalization. In summary, the PEG- and PEI-conjugated CNTs may be used as novel nanocarriers and the findings will contribute to the rational design of multifunctional delivery vehicles for anticancer drugs.

James G Shamul,1,2,* Sagar R Shah,1–3,* Jayoung Kim,1,2 Paula Schiapparelli,3 Carla A Vazquez-Ramos,3 Ben J Lee,1,2 Kisha K Patel,1,2 Alyssa Shin,1,2 Alfredo Quinones-Hinojosa,3 Jordan J Green1,2,4–6 1Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21231, USA; 2Translational Tissue Engineering Center and Institute for NanoBioTechnology, Johns Hopkins School of Medicine, Baltimore, MD 21231, USA; 3Department of Neurosurgery, Mayo Clinic, Jacksonville, FL 32224, USA; 4Department of Neurosurgery, Johns Hopkins Hospital, Baltimore, MD 21231, USA; 5Department of Oncology, The Sidney Kimmel Comprehensive Cancer, and The Bloomberg∼Kimmel Institute for Cancer Immunotherapy, Johns Hopkins School of Medicine, Baltimore, MD 21231, USA; 6Department of Ophthalmology, Department of Materials Science and Engineering, and Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21231, USA*These authors contributed equally to this workCorrespondence: Alfredo Quinones-Hinojosa; Jordan J Green Email Quinones-Hinojosa.Alfredo@mayo.edu; green@jhu.eduBackground: Nanomedicine can improve traditional therapies by enhancing the controlled release of drugs at targeted tissues in the body. However, there still exists disease- and therapy-specific barriers that limit the efficacy of such treatments. A major challenge in developing effective therapies for one of the most aggressive brain tumors, glioblastoma (GBM), is affecting brain cancer cells while avoiding damage to the surrounding healthy brain parenchyma. Here, we developed poly(ethylene glycol) (PEG)-poly(beta-amino ester) (PBAE) (PEG-PBAE)-based micelles encapsulating verteporfin (VP) to increase tumor-specific targeting.Methods: Biodegradable, pH-sensitive micelles of different shapes were synthesized via nanoprecipitation using two different triblock PEG-PBAE-PEG copolymers varying in their relative hydrophobicity. The anti-tumor efficacy of verteporfin loaded in these anisotropic and spherical micelles was evaluated in vitro using patient-derived primary GBM cells.Results: For anisotropic micelles, uptake efficiency was ∼100% in GBM cells (GBM1A and JHGBM612) while only 46% in normal human astrocytes (NHA) at 15.6 nM VP (p ≤ 0.0001). Cell killing of GBM1A and JHGBM612 vs NHA was 52% and 77% vs 29%, respectively, at 24 hrs post-treatment of 125 nM VP-encapsulated in anisotropic micelles (p ≤ 0.0001), demonstrating the tumor cell-specific selectivity of VP. Moreover, anisotropic micelles showed an approximately fivefold longer half-life in blood circulation than the analogous spherical micelles in a GBM xenograft model in mice. In this model, micelle accumulation to tumors was significantly greater for anisotropic micelle-treated mice compared to spherical micelle-treated mice at both 8 hrs (∼1.8-fold greater, p ≤ 0.001) and 24 hrs (∼2.1-fold greater, p ≤ 0.0001).Conclusion: Overall, this work highlights the promise of a biodegradable anisotropic micelle system to overcome multiple drug delivery challenges and enhance efficacy and safety for the treatment of brain cancer.Keywords: GBM, verteporfin, micelle, anisotropic, poly(ethylene glycol), PEG, poly(beta-amino ester), PBAE

Polymeric-micelle carrier systems have emerged as a novel drug-carrier system and have been actively studied for anticancer drug targeting. In contrast, toxicological and immunological concerns related to not only polymeric-micelle carrier systems, but also other nanocarrier systems, have received little attention owing to researchers’ focus on therapeutic effects. However, in recent clinical contexts, biopharmaceuticals’ effects on immune responses have come to light, requiring that researchers substantively explore the potential negative side effects of nanocarrier systems and of therapeutic proteins in order to develop nanocarrier systems suitable for clinical use. The present review describes current insights into both toxicological and immunological issues regarding polymeric-micelle carrier systems. The review focuses on immunogenicity issues of polymeric-micelle carrier systems possessing poly(ethylene glycol) (PEG). We conclude that PEG-related immunogenicity is deeply related to characteristics of a counterpart block of PEG-conjugates, and we propose future directions for addressing this unresolved issue.

[Display omitted] Hybrid solvents based on cholinium amino acid ionic liquids ([Ch][AA] ILs) mixed with water are environmentally benign solvents with low toxicity. [Ch][AA] ILs are used in biomass pretreatment processes to dissolve targeted (macro)molecules such as lignin from lingnocellulose. Understanding how [Ch][AA] ILs dissolve polymers is therefore of great interest for the rational design of ILs towards industrial application. Variation of the IL anion and the water concentration are hypothesised to change the solvent properties of [Ch][AA] hybrid solvents. Therefore, we probe the solvent quality of [Ch][AA] aqueous solutions with different anions (glycinate, prolinate and argininate) and water concentration for the simple model solute poly(ethylene glycol) (PEG). Partial phase diagrams were produced to probe the salting-out effect of [Ch][AA] ILs towards PEG (M w = 38 kDa). Small-angle neutron scattering experiments of deuterated PEG in hydrogenous [Ch][AA] aqueous solutions were performed to determine the polymer radius of gyration at infinite dilution (R g,0) via Zimm-plots. Polymer concentration dependent apparent R g values were obtained fitting an excluded volume polymer model onto the scattering data. Blends of hydrogenous and deuterated PEG under zero average contrast conditions were analysed to probe R g at high polymer concentrations. Hydrogen bond capacity of the anion is key to the salting-out effect of [Ch][AA] ILs on PEG. R g,0 depends on anion species and water concentration. At IL:water = 1:30 (mole:mole) and 37 °C, cholinium argininate and cholinium glycinate are close to theta solvents while cholinium prolinate and dilute cholinium argininate (IL:water = 1:100) are between theta and good solvents. [ABSTRACT FROM AUTHOR]

Recently, multifunctional polymers for protein conjugation have been facilely synthesized through the multicomponent reactions (MCRs). In this mini‐review, current progress in the generation of multifunctional polymers with protein‐reactive groups via MCRs is summarized. These multifunctional polymers react with model therapeutic proteins, forming multifunctional polymer‐protein conjugates, which are prototypes of sophisticated theranostic agents and antibacterial vaccine candidates. In comparison with the traditional multi‐step synthesis, the preparation of multifunctional polymers for protein conjugation through MCRs is straightforward and convenient. Due to these properties, MCRs have the potential to become a new general strategy to achieve polymer‐protein conjugates for biological and medical applications. [ABSTRACT FROM AUTHOR]

Neutron spin‐echo spectroscopy is a unique experimental method for the investigation of polymer dynamics. The combination of neutron spin‐echo spectroscopy with grazing‐incidence geometry (GINSES) opens the possibility to probe the dynamics of soft‐matter materials in the vicinity of the solid substrate in the time range up to 100 ns. However, the usage of the GINSES technique has some peculiarities and, due to the novelty of the method and complexity of the scattering geometry, difficulties in further data analysis occur. The current work discusses how virtual experiments within the distorted‐wave Born approximation using the BornAgain software can improve GINSES data treatment and aid the understanding of polymer dynamics in the vicinity of the solid surface. With two examples, poly(N‐isopropyl acrylamide) brushes and poly(ethylene glycol) microgels on Si surfaces, the simulation as well as the application of the simulation to the GINSES data analysis are presented. The approach allowed a deeper insight to be gained of the background effect and scattering contribution of different layers. [ABSTRACT FROM AUTHOR]

Polymeric-micelle carrier systems have emerged as a novel drug-carrier system and have been actively studied for anticancer drug targeting. In contrast, toxicological and immunological concerns related to not only polymeric-micelle carrier systems, but also other nanocarrier systems, have received little attention owing to researchers' focus on therapeutic effects. However, in recent clinical contexts, biopharmaceuticals' effects on immune responses have come to light, requiring that researchers substantively explore the potential negative side effects of nanocarrier systems and of therapeutic proteins in order to develop nanocarrier systems suitable for clinical use. The present review describes current insights into both toxicological and immunological issues regarding polymeric-micelle carrier systems. The review focuses on immunogenicity issues of polymeric-micelle carrier systems possessing poly(ethylene glycol) (PEG). We conclude that PEG-related immunogenicity is deeply related to characteristics of a counterpart block of PEG-conjugates, and we propose future directions for addressing this unresolved issue. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) (PEG) is used in many common products, such as cosmetics. PEG, however, is also used to covalently conjugate drug molecules, proteins, or nanocarriers, which is termed PEGylation, to serve as a shield against the natural immune system of the human body. Repeated administration of some PEGylated products, however, is known to induce anti-PEG antibodies. In addition, preexisting anti-PEG antibodies are now being detected in healthy individuals who have never received PEGylated therapeutics. Both treatment-induced and preexisting anti-PEG antibodies alter the pharmacokinetic properties, which can result in a subsequent reduction in the therapeutic efficacy of administered PEGylated therapeutics through the so-called accelerated blood clearance (ABC) phenomenon. Moreover, these anti-PEG antibodies are widely reported to be related to severe hypersensitivity reactions following the administration of PEGylated therapeutics, including COVID-19 vaccines. We recently reported that the topical application of a cosmetic product containing PEG derivatives induced anti-PEG immunoglobulin M (IgM) in a mouse model. Our finding indicates that the PEG derivatives in cosmetic products could be a major cause of the preexistence of anti-PEG antibodies in healthy individuals. In this study, therefore, the pharmacokinetics and therapeutic effects of Doxil (doxorubicin hydrochloride-loaded PEGylated liposomes) and oxaliplatin-loaded PEGylated liposomes (Liposomal l-OHP) were studied in mice. The anti-PEG IgM antibodies induced by the topical application of cosmetic products obviously accelerated the blood clearance of both PEGylated liposomal formulations. Moreover, in C26 tumor-bearing mice, the tumor growth suppressive effects of both Doxil and Liposomal l-OHP were significantly attenuated in the presence of anti-PEG IgM antibodies induced by the topical application of cosmetic products. These results confirm that the topical application of a cosmetic product containing PEG derivatives could produce preexisting anti-PEG antibodies that then affect the therapeutic efficacy of subsequent doses of PEGylated therapeutics.

Synthetic hydrogels are widely used as artificial 3D environments for cell culture, facilitating the controlled study of cell-environment interactions. However, most hydrogels are limited in their ability to represent the physical properties of biological tissues because stiffness and solute transport properties in hydrogels are closely correlated. Resultingly, experimental investigations of cell-environment interactions in hydrogels are confounded by simultaneous changes in multiple physical properties. Here, we overcame this limitation by simultaneously manipulating four structural parameters to synthesize a library of multi-arm poly (ethylene glycol) (PEG) hydrogel formulations with robustly decoupled stiffness and solute transport. This structural design approach avoids chemical alterations or additions to the network that might have unanticipated effects on encapsulated cells. An algorithm created to statistically evaluate stiffness-transport decoupling within the dataset identified 46 of the 73 synthesized formulations as robustly decoupled. We show that the swollen polymer network model accurately predicts 11 out of 12 structure-property relationships, suggesting that this approach to decoupling stiffness and solute transport in hydrogels is fundamentally validated and potentially broadly applicable. Furthermore, the unprecedented control of hydrogel network structure provided by multi-arm PEG hydrogels confirmed several fundamental modeling assumptions. This study enables nuanced hydrogel design for uncompromised investigation of cell-environment interactions. [ABSTRACT FROM AUTHOR]

Different forms of unmodified and modified Poly(ethylene glycols) (PEGs) are widely used as antifouling and antibacterial agents for biomedical industries and Nylon 6 is one of the polymers used for biomedical textiles. Our recent study focused on an efficient approach to PEG immobilization on a reduced Nylon 6 surface via N,N′–disuccinimidyl carbonate (DSC) conjugation. The conversion of amide functional groups to secondary amines on the Nylon 6 polymer surface was achieved by the reducing agent borane-tetrahydrofuran (BH3–THF) complex, before binding the PEG. Various techniques, including water contact angle and free surface energy measurements, atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy, were used to confirm the desired surface immobilization. Our findings indicated that PEG may be efficiently tethered to the Nylon 6 surface via DSC, having an enormous future potential for antifouling biomedical materials. The bacterial adhesion performances against S. aureus and P. aeruginosa were examined. In vitro cytocompatibility was successfully tested on pure, reduced, and PEG immobilized samples.

Gelatin hydrogels are used as three-dimensional cell scaffolds and can be prepared using various methods. One widely accepted approach involves crosslinking gelatin amino groups with poly(ethylene glycol) (PEG) modified with N -hydroxysuccinimide ester (PEG-NHS). This method enables the encapsulation of live cells within the hydrogels and also facilitates the adhesion of the hydrogel to biological tissues by crosslinking their surface amino groups. Consequently, these hydrogels are valuable tools for immobilizing cells that secrete beneficial substances in vivo. However, the application of gelatin hydrogels is limited due to the requirement for several minutes to solidify under conditions of neutral pH and polymer concentrations suitable for live cells. This limitation makes it impractical for use with biological tissues, which have complex shapes or inclined surfaces, restricting its application to semi-closed spaces. In this study, we propose a tissue-adhesive hydrogel that can be sprayed and immobilized with live cells on biological tissue surfaces. This hydrogel system combines two components: (1) gelatin/PEG-NHS hydrogels and (2) instantaneously solidifying PEG hydrogels. The sprayed hydrogel solidified within 5 s after dispensing while maintaining the adhesive properties of the PEG-NHS component. The resulting hydrogels exhibited protein permeability, and the viability of encapsulated human mesenchymal stem/stromal cells (hMSCs) remained above 90% for at least 7 days. This developed hydrogel system represents a promising approach for immobilizing live cells on tissue surfaces with complex shapes.

Graphical abstract Highlights • Aqueous two-phase systems composed of PEG and NaPA + inorganic salts were studied. • PEG/NaPA + salts-based ATPS were employed to GFP recovery and LPS removal. • PEG/NaPA + Li 2 SO 4 presented LPS removal (REM LPS) values of 13. • PEG/NaPA + salts showed high partition coefficients of GFP (K GFP > 20). • PEG/NaPA + Li 2 SO 4 promoted purification factor of 4-fold, and selectivity of 20. Abstract The production of recombinant biopharmaceuticals is highly dependent of a proper choice of the downstream processing stages. Particularly, the purification that must ensure that all the endotoxins (lipopolysaccharides - LPS) are efficiently removed from the final product. The efficient removal of LPS has a direct impact on the manufacturing of therapeutic biopharmaceuticals, since LPS is naturally presented in Gram-negative bacterial expression systems. In order to provide a more simple and faster technique for the purification of green fluorescent protein (GFP) and LPS removal, aqueous two-phase systems (ATPS) composed of polyethylene glycol (PEG) and poly(acrylic acid) (NaPA) and electrolytes were studied. Firstly, the binodal curves of PEG/NaPA + salt systems were established using NaCl, Li 2 SO 4 , KI, and KNO 3 as additives. It was demonstrated that the formation of ATPS is enhanced following the anion tendency: SO 4 2− > Cl− ≫ NO 3 − > I−. The stability of GFP in the presence of all different phase forming agents (polymers and salts) was evaluated, and the high biocompatibility of these ATPS demonstrated by the maintenance of GFP fluorescence in all conditions under study. Then, the GFP extraction and LPS removal aptitude of each ATPS was investigated. GFP and LPS were preferentially partitioned into the top (PEG-rich) phase (K GFP > 20), but with a removal of 35% of LPS was attained. Hydrophobic and electrostatic interactions were found to be the major driving forces for GFP partitioning and LPS removal. Moreover, a new effect was found, the presence of high loads of LPS can affect (decrease) the K GFP values (K GFP without LPS > K GFP with 104 EU/mL > K GFP with 106 EU/mL). The ATPS with best GFP extraction performance was selected for the recovery directly from the cell lysates of Escherichia coli. In this experiment, the system composed of 12 wt% PEG 1000 g/mol, 12 wt% NaPA 8000 g/mol, and 0.25 M Li 2 SO 4 lead to a LPS removal (REM LPS) of 13%, K GFP of 20.2, and high selectivity relatively to the total proteins (S = 20), since the majority of contaminants proteins were preferentially partitioned into the bottom (NaPA-rich) phase (purification factor of 4-fold). It is here demonstrated that the ATPS composed of PEG/NaPA + salts as additives can be used as a first step for the recovery of GFP and removal of contaminants (LPS in part, and most contaminant proteins) from cell lysates by applying a system with low polymer content and using mild conditions. [ABSTRACT FROM AUTHOR]

Hypothesis Poly(carboxylate ether)-based (PCE) superplasticizers consist of a carboxylic acid backbone and grafted poly(ethylene glycol) (PEG) side chains. Ca 2+ ion bridging mechanism is commonly purported to control PCE’s adsorption on negatively charged cement particle surfaces in cement suspension, thus PCE was expected to adsorb on negatively charged surfaces in synthetic pore solutions via Ca 2+ / COO − interactions. Experiments Adsorption behaviors of a commercial PCE on negatively charged mica were studied in aqueous electrolyte solutions by a surface forces apparatus. Findings Direct force measurements indicated that the PCE adsorbed onto mica from 0.1 M K 2 SO 4 due to K + ion chelation by the ether oxygen units CH 2 CH 2 O on the PEG chains, but surprisingly did not adsorb from either 0.1 M K 2 SO 4 with saturated Ca(OH) 2 or 0.1 M Ca(NO 3 ) 2 . The adsorption in K 2 SO 4 was weak, enabling the adsorbed PCE layers to be squeezed out under modest compression. Upon separating the surfaces, the PCE immediately achieved an identical re-adsorption. In high-calcium conditions, the PCE was highly positively charged due to Ca 2+ ion chelation by PEG chains and backbone carboxylic groups COO − , and mica also underwent charge reversal due to electrostatic adsorption/binding of Ca 2+ ions. Consequently, the interaction between mica and PCE was electrostatically repulsive and no PCE adsorption occurred. These findings can be explained by the complex interplay of ion chelation by PEG chains, electrostatic binding and screening interactions with charged surfaces in the presence of monovalent and divalent counterions, and ultimately charge reversal of both the charged surfaces and polyelectrolyte in high divalent ion conditions. [ABSTRACT FROM AUTHOR]

We measured the attenuated total reflectance-far ultraviolet (ATR-FUV) spectra of poly(ethylene glycol) (PEG; average molecular weights of 200, 300, and 400) and related materials in the liquid state in the 145–200-nm wavelength region. For appropriately assigning the absorption bands, we also performed theoretical simulation of the unit-number dependent electronic spectra. The FUV spectra of PEGs contain three bands, which are assigned to the transitions between n(CH 2 OCH 2 )-3s Rydberg state (176 nm), n(CH 2 OCH 2 )-3p Rydberg state (163 nm), and n(OH)-3p Rydberg state (153 nm). Since the contribution of n(OH) decreases compared to n(CH 2 OCH 2 ) with increase in the number of units, the ratios of the molar absorption coefficients, ε, at 153 nm relative to 163 nm, decrease. On the other hand, the ratio of ε at 176 nm to that at 163 nm increases with increase in the number of units, because of the difference in the number of unoccupied orbitals in the transitions. The calculated results suggest that n orbitals form two electronic bands. In the upper band, the electrons expand over the ether chain, whereas in the lower band, the electrons are localized in the terminal OH in the PEGs. [ABSTRACT FROM AUTHOR]

A series of polyethylene glycol‐containing imidazolium‐functionalized phosphine ligands (mPEG‐im‐PPh2) were successfully synthesized and used in the rhodium‐catalyzed hydrosilylation of olefins. The results indicate that the RhCl3/mPEG‐im‐PPh2 catalytic system exhibits both excellent activity and selectivity for the β‐adduct. In addition, the catalytic system may be recycled at least six times. [ABSTRACT FROM AUTHOR]

The partitioning of bacteriocin, a promising alternative to chemical preservatives, in a novel inexpensive and stable aqueous two-phase system (ATPS) comprising poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) was studied. The ATPS was generated by mixing both polymers with Na 2 SO 4 or choline chloride ([Ch]Cl) and a bacteriocin extract from the fermented broth of Lactobacillus plantarum ST16Pa. Bacteriocin showed stability at different pH values (3.0–8.0) and temperatures (50–80 °C), as well as in the presence of ATPS components. Hydrophobic and electrostatic interactions were found to be the major driving forces for bacteriocin partitioning. The peptide partitioned preferentially to the PEG-rich phase (partition coefficient, K Bact > 1). However, the highest partition coefficient was achieved in the polymeric-based ATPS using [Ch]Cl as additive, as follows: 8 wt% PEG 10,000 g/mol/8 wt% NaPA 8,000 g/mol/0.5 M [Ch]Cl, resulting in a K Bact equal to 32. Moreover, these conditions promoted high selectivity ( S = 62.7), since the greater part of total proteins partitioned into the NaPA-rich phase ( K prot = 0.51). In conclusion, ATPS composed of PEG/NaPA using choline-based salts as additive can be considered mainly as a first step for bacteriocin extraction from fermented broth by applying low polymer content and mild conditions. [ABSTRACT FROM AUTHOR]

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The last decade has seen the emergence of vascular-targeted drug delivery systems as a promising approach for the treatment of many diseases, such as cardiovascular diseases and cancer. In this field, one of the major challenges is carrier margination propensity (i.e., particle migration from blood flow to vessel walls); indeed, binding of these particles to targeted cells and tissues is only possible if there is direct carrier-wall interaction. Here, a microfluidic system mimicking the hydrodynamic conditions of human microcirculation in vitro is used to investigate the effect of red blood cells (RBCs) on a carrier margination in relation to RBC concentration (hematocrit) and pressure drop. As model drug carriers, fluorescent polymeric nanoparticles (FNPs) were chosen, which were obtained by using as starting material a pegylated polylactic acid-polyaspartamide copolymer. The latter was synthesized by derivatization of α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) with Rhodamine (RhB), polylactic acid (PLA) and then poly(ethyleneglycol) (PEG) chains. It was found that the carrier concentration near the wall increases with increasing pressure drop, independently of RBC concentration, and that the tendency for FNP margination decreases with increasing hematocrit. This work highlights the importance of taking into account RBC-drug carrier interactions and physiological conditions in microcirculation when planning a drug delivery strategy based on systemically administered carriers. [ABSTRACT FROM AUTHOR]

Produced via electrospinning, polyurethane (PU) scaffolds have always attracted the interest of medical applications due of their unique properties such as good adhesion, biocompatibility and excellent mechanical strength. However, the poor hydrophilicity and hemocompatibility of PU presented a problem during PU's application in the manufacturing of biomedical materials. We hypothesized that the incorporation of polyethylene glycol (PEG) and phosphatidylcholine (PC) into electrospinning solution of PU could improve the cell affinity and hemocompatibility. This research focused on fabricating hybrid PU-PEG and PU-PC random/aligned scaffolds through electrospinning technique and comparing their properties as a potential biocompatible scaffold for vascular tissue engineering. PC was doped into a PU solution in order to prepare an electrospun scaffold through the electrospinning technology while crosslinked electrospun PUPEG hybrid scaffolds were fabricated by photoinduced polymerization. The contact angle dramatically decreased from 122.3±0.8° to 39.1±0.8° with doping of PC in electrospinning solution while it decreased from 122.3±0.8° to 41.6±0.8° with doping of PEG. Furthermore, the mechanical properties of PU scaffolds were altered significantly by the addition of PC. The hemolysis and cytocompatibility assays demonstrated that these composite scaffolds could potentially be used as a smalldiameter vascular graft. [ABSTRACT FROM AUTHOR]

Chemical conjugation or blending with poly(ethylene glycols) (PEGs) are established procedures to facilitate solubilisation of hydrophobic compounds. The techniques of bioPEGylation and blending with PEG were applied to poly(3-hydroxybutyrate). In this paper we have examined the properties of copolymer of poly(3-hydroxybutyrate-co-poly(ethylene glycol)) (PHB-PEG) and composite material polyhydroxybutyrate with poly(ethylene glycol) (PHB + PEG) compared to homopolymer of poly(3-hydroxybutyrate) (PHB). It was found that copolymer has significally different mechanical and thermophysical properties with respect to pure PHB: an increased crystallinity but a decreased Young's modulus and elongation at break. Moreover, the creation of the composite, and a copolymer of PHB with PEG results in a change in surface morphology of ultrathin films. [ABSTRACT FROM AUTHOR]

This paper describes the evaluation of polymeric nanoparticles (NPs) as a potential carrier for lung administration of fluticasone propionate (FP). The chosen polymeric material to produce NPs was a copolymer based on α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) whose backbone was derivatised with different molecules, such as poly(lactic acid) (PLA) and polyethylenglycol (PEG). The chosen method to produce NPs from PHEA-PLA-PEG2000 was the method based on high-pressure homogenization and subsequent solvent evaporation by adding Pluronic F68 during the process and trehalose before lyophilisation. Obtained colloidal FP-loaded NPs showed a slightly negative surface charge and nanometric dimensions that are maintained after storage for one year at -20 °C and 5 °C. The FP loading was about 2.9 wt % and the drug was slowly released in simulated lung fluid. Moreover, the obtained NPs, containing the drug or not, were biocompatible and did not induce cell necrosis and cell apoptosis on bronchial epithelial cells (16-HBE). Further in vitro testing on cigarette smoke extract (CSE)-stimulated 16-HBE revealed that FP-loaded NPs were able to reduce the survivin expression, while either free FP or empty NPs were not able to significantly reduce this effect. [ABSTRACT FROM AUTHOR]

Islet transplantation is a promising therapy for Type 1 diabetes mellitus; however, host inflammatory and immune responses lead to islet dysfunction and destruction, despite potent systemic immunosuppression. Grafting of poly(ethylene glycol) (PEG) to the periphery of cells or tissues can mitigate inflammation and immune recognition via generation of a steric barrier. Herein, we sought to evaluate the complementary impact of islet PEGylation with a short-course immunotherapy on the survival of fully-MHC mismatched islet allografts (DBA/2 islets into diabetic C57BL/6J recipients). Anti-Lymphocyte Function-associated Antigen 1 (LFA-1) antibody was selected as a complementary, transient, systemic immune monotherapy. Islets were PEGylated via an optimized protocol, with resulting islets exhibiting robust cell viability and function. Following transplantation, a significant subset of diabetic animals receiving PEGylated islets (60%) or anti-LFA-1 antibody (50%) exhibited long-term (>100 d) normoglycemia. The combinatorial approach proved synergistic, with 78% of the grafts exhibiting euglycemia long-term. Additional studies examining graft cellular infiltrates at early time points characterized the local impact of the transplant protocol on graft survival. Results illustrate the capacity of a simple polymer grafting approach to impart significant immunoprotective effects via modulation of the local transplant environment, while short-term immunotherapy serves to complement this effect. Statement of Significance We believe this study is important and of interest to the biomaterials and transplant community for several reasons: 1) it provides an optimized protocol for the PEGylation of islets, with minimal impact on the coated islets, which can be easily translated for clinical applications; 2) this optimized protocol demonstrates the benefits of islet PEGylation in providing modest immunosuppression in a murine model; 3) this work demonstrates the combinatory impact of PEGylation with short-course immunotherapy (via LFA-1 blockage), illustrating the capacity of PEGylation to complement existing immunotherapy; and 4) it suggests macrophage phenotype shifting as the potential mechanism for this observed benefit. [ABSTRACT FROM AUTHOR]

The antibacterial potential of silver nanoparticles (AgNPs) resulted in their increasing incorporation into consumer, industrial and biomedical products. Therefore, human and environmental exposure to AgNPs (either as an engineered product or a contaminant) supports the emergent research on the features conferring them different toxicity profiles. In this study, 30 nm AgNPs coated with citrate or poly(ethylene glycol) (PEG) were used to assess the influence of coating on the effects produced on a human hepatoma cell line (HepG2), namely in terms of viability, apoptosis, apoptotic related genes, cell cycle and cyclins gene expression. Both types of coated AgNPs decreased cell proliferation and viability with a similar toxicity profile. At the concentrations used (11 and 5 μg/mL corresponding to IC50 and ~ IC10 levels, respectively) the amount of cells undergoing apoptosis was not significant and the apoptotic related genes BCL2 (anti-apoptotic gene) and BAX (pro-apoptotic gene) were both downregulated. Moreover, both AgNPs affected HepG2 cell cycle progression at the higher concentration (11 μg/mL) by increasing the percentage of cells in S (synthesis phase) and G2 (Gap 2 phase) phases. Considering the cell-cycle related genes, the expression of cyclin B1 and cyclin E1 genes were decreased. Thus, this work has shown that citrate- and PEG-coated AgNPs impact on HepG2 apoptotic gene expression, cell cycle dynamics and cyclin regulation in a similar way. More research is needed to determine the properties that confer AgNPs at lower toxicity, since their use has proved helpful in several industrial and biomedical contexts. [ABSTRACT FROM AUTHOR]

Amphiphilic surfaces are particularly effective at inhibiting the adhesion of microorganisms (bacteria, cells, microalgae, etc.) in liquid media. The aim of this study is to determine the best hydrophilic linker to promote bonding between poly(ethylene glycol) (PEG) as a hydrophilic additive and poly(dimethyl siloxane) (PDMS) as the hydrophobic matrix. Various parameters have been studied (molecular weight, linker type, and polymer end-group), as well as the efficiency of the linking, the capacity of PEG to access to the surface of the film, and overall film homogeneity. According to the results, a PDMS linker paired with a PEG moiety allows for compatibilization of the compounds during cross-linking. This compatibilization seems to provide a good bonding with the matrix and a good surface access to the hydrophilic moiety. Therefore, this structure comprising a linking function attached to the PDMS–PEG copolymer has high potential as a non-releasable additive for amphiphilic coating applications.

In this study, composites of lead element, which is used to eliminate the harmful effects of radiation, were prepared with a polymer blend with shape memory properties. Poly(lactic acid) (PLA)/Poly(ethylene glycol) (PEG) blend films doped with different amounts of lead were obtained by solvent casting method. Polymer blend/Pb composites were characterized by Attenuated total reflectance infrared spectroscopy (ATR-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscope (SEM). When the thermal analysis results were examined, it was observed that the thermal stability of the polymer blend decreased as the Pb percentage increased. It was concluded that the shape memory properties were the best in the polymer blend containing 4% Pb. X-ray diffraction (XRD) results showed that the 2Ɵ peaks at 31.2°, 36.3°, 52.3°, 62.1° and 65.2° represent Pb with a characteristic cubic shape. It was calculated from XRD that the polymer blend composite containing 16% Pb had the highest degree of crystallinity with 31.41%. Finally, in the study, the gamma irradiation of the obtained polymer blend/Pb composites were examined. It was seen that the linear absorption capacity increased with increasing Pb percentage, which can be interpreted as an increase in the shielding ability. • PLA/PEG Blend composites doped with different percentages of lead were produced. • It was observed that the thermal stability of the polymer blend composite decreased as the Pb percentage increased. • The shape memory effect is best in the composite containing 4% Pb. • XRD signals of cubic shaped Pb were determined. • The gamma rays absorption effect increased significantly with the percentage of Pb. [ABSTRACT FROM AUTHOR]

The last decade has seen the emergence of vascular-targeted drug delivery systems as a promising approach for the treatment of many diseases, such as cardiovascular diseases and cancer. In this field, one of the major challenges is carrier margination propensity (i.e., particle migration from blood flow to vessel walls); indeed, binding of these particles to targeted cells and tissues is only possible if there is direct carrier–wall interaction. Here, a microfluidic system mimicking the hydrodynamic conditions of human microcirculation in vitro is used to investigate the effect of red blood cells (RBCs) on a carrier margination in relation to RBC concentration (hematocrit) and pressure drop. As model drug carriers, fluorescent polymeric nanoparticles (FNPs) were chosen, which were obtained by using as starting material a pegylated polylactic acid–polyaspartamide copolymer. The latter was synthesized by derivatization of α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) with Rhodamine (RhB), polylactic acid (PLA) and then poly(ethyleneglycol) (PEG) chains. It was found that the carrier concentration near the wall increases with increasing pressure drop, independently of RBC concentration, and that the tendency for FNP margination decreases with increasing hematocrit. This work highlights the importance of taking into account RBC–drug carrier interactions and physiological conditions in microcirculation when planning a drug delivery strategy based on systemically administered carriers.

Adhesive processes in aqueous media play a crucial role in nature and are important for many technological processes. However, direct quantification of adhesion still requires expensive instrumentation while their sample throughput is rather small. Here we present a fast, and easily applicable method on quantifying adhesion energy in water based on interferometric measurement of polymer microgel contact areas with functionalized glass slides and evaluation via the Johnson–Kendall–Roberts (JKR) model. The advantage of the method is that the microgel matrix can be easily adapted to reconstruct various biological or technological adhesion processes. Here we study the suitability of the new adhesion method with two relevant examples: (1) antibody detection and (2) soil release polymers. The measurement of adhesion energy provides direct insights on the presence of antibodies showing that the method can be generally used for biomolecule detection. As a relevant example of adhesion in technology, the antiadhesive properties of soil release polymers used in today’s laundry products are investigated. Here the measurement of adhesion energy provides direct insights into the relation between polymer composition and soil release activity. Overall, the work shows that polymer hydrogel particles can be used as versatile adhesion sensors to investigate a broad range of adhesion processes in aqueous media.

This paper describes the evaluation of polymeric nanoparticles (NPs) as a potential carrier for lung administration of fluticasone propionate (FP). The chosen polymeric material to produce NPs was a copolymer based on α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) whose backbone was derivatised with different molecules, such as poly(lactic acid) (PLA) and polyethylenglycol (PEG). The chosen method to produce NPs from PHEA-PLA-PEG2000 was the method based on high-pressure homogenization and subsequent solvent evaporation by adding Pluronic F68 during the process and trehalose before lyophilisation. Obtained colloidal FP-loaded NPs showed a slightly negative surface charge and nanometric dimensions that are maintained after storage for one year at −20 °C and 5 °C. The FP loading was about 2.9 wt % and the drug was slowly released in simulated lung fluid. Moreover, the obtained NPs, containing the drug or not, were biocompatible and did not induce cell necrosis and cell apoptosis on bronchial epithelial cells (16-HBE). Further in vitro testing on cigarette smoke extract (CSE)-stimulated 16-HBE revealed that FP-loaded NPs were able to reduce the survivin expression, while either free FP or empty NPs were not able to significantly reduce this effect.

Though l-arginine-containing polymers show versatile biological functions, a precisely controlled synthesis of poly(ethylene glycol)- b-poly( l-arginine) (PEG- b-PArg) block copolymers has not been reported. Here, an effective method for the synthesis of PEG- b-PArg block copolymers is developed. In order to obtain PEG- b-PArg, a two-step reaction, i.e., synthesis of PEG- b-poly( l-ornithine) is employed, followed by guanidinylation with N, N′-bis( tert-butoxycarbonyl)-1 H-pyrazole-1-carboxamidine. This procedure quantitatively converts amino groups to guanidium groups at the side chains of peptide segments under mild conditions. Polyion complex (PIC) micelles are prepared by mixing the positively charged PEG- b-PArg with negatively charged homo-polyelectrolytes such as hyaluronic acid (HA) or chondroitin sulfate C (CS). PIC micelles prepared with CS show a higher stability than those prepared with HA, probably due to strong interactions between guanidium cations in PEG- b-PArg and carboxylate/sulfate in CS. Thus, PIC micelles containing PArg are a potentially effective arginine carrier for the development of in vivo therapeutic applications for various diseases related to nitric oxide, which is generated from inducible nitric oxide synthase in macrophages using l-arginine as a substrate. [ABSTRACT FROM AUTHOR]

Here, the synthesis of two graft copolymers based on α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) and poly(lactic acid) (PLA), the O-(2-aminoethyl)-O′-galactosyl polyethylene glycol (GAL-PEG-NH 2 ) or the methoxypolyethylene glycol amine (H 2 N-PEG-OCH 3 ) is described. Starting from the obtained PHEA-PLA-PEG-GAL and PHEA-PLA-PEG copolymers, polymeric nanoparticles were prepared by high pressure homogenization–solvent evaporation method. To demonstrate their biodegradability as a function of the matrix composition, a chemical stability study was carried out until 21 days by incubating systems in two media mimicking physiological compartments (pH 7.4 and pH 5.5). The degradability of both nanosystems was firstly confirmed by the reduction of the pH of the incubation medium. Moreover, the percentage yield of recovered nanoparticles show a gradual reduction while mean size increases as a function of incubation time. Degradation seems to be mainly attributed to the loss of water-soluble portions of PLA, and proceeds with greater speed at pH 5.5, than at pH 7.4 and as a function of matrix composition. [ABSTRACT FROM AUTHOR]

In our continuing search for camptothecin (CPT)-derived antitumor drugs, novel structurally diverse PEG-based 20( S )-CPT sulfonylamidine derivatives were designed, synthesized via a Cu-multicomponent reaction (MCR), and evaluated for cytotoxicity against four human tumor cell lines (A-549, MDA-MB-231, KB, and KBvin). All of the derivatives showed promising in vitro cytotoxic activity against the tested tumor cell lines, and were more potent than irinotecan. Significantly, these derivatives exhibited comparable cytotoxicity against KBvin, while irinotecan was less active against this cell line. With a concise efficient synthesis and potent cytotoxic profiles, especially significant activity towards KBvin, these compounds merit further development as a new generation of CPT-derived PEG-conjugated drug candidates. [ABSTRACT FROM AUTHOR]

Nerve repair scaffolds from novel alternating block polyurethanes (PUCL- alt-PEG) based on PCL and PEG without additional growth factors or proteins were prepared by a particle leaching method. The scaffolds have pore size 10−20 µm and porosity 92%. Mechanical tests showed that the polyurethane scaffolds have maximum loads of 5.97 ± 0.35 N and maximal stresses of 8.84 ± 0.5 MPa. Histocompatiblity of the nerve repair scaffolds was tested in a SD rat model for peripheral nerve defect treatment. Two types of treatments including PUCL- alt-PEG scaffolds and autografts were compared in rat model. After 32 weeks, bridging of a 12 mm defect gap by the regenerated nerve was observed in all rats. The nerve regeneration was systematically characterized by sciatic function index (SFI), electrophysiology, histological assessment including HE staining, immunohistochemistry, ammonia sliver staining, Masson's trichrome staining and TEM observation. Results revealed that nerve repair scaffolds from PUCL- alt-PEG exhibit better regeneration effects compared to autografts. Electrophysiological recovery was seen in 90% and 87% of rats in PUCL- alt-PEG and autograft groups respectively. Biodegradation in vitro and in vivo shows good degradation match of PUCL- alt-PEG scaffolds with nerve regeneration. It demonstrates that plain nerve repair scaffolds from PUCL- alt-PEG biomaterials can achieve peripheral nerve regeneration satisfactorily. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103: 2355-2364, 2015. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) (PEG)–protein therapeutics exhibit enhanced pharmacokinetics, but have drawbacks including decreased protein activities and polymer accumulation in the body. Therefore a major aim for second-generation polymer therapeutics is to introduce degradability into the backbone. Herein we describe the synthesis of poly(poly(ethylene glycol methyl ether methacrylate)) (pPEGMA) degradable polymers with protein-reactive end-groups via reversible addition–fragmentation chain transfer (RAFT) polymerization, and the subsequent covalent attachment to lysozyme through a reducible disulfide linkage. RAFT copolymerization of cyclic ketene acetal (CKA) monomer 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) with PEGMA yielded two polymers with number-average molecular weight ( M n ) (GPC) of 10.9 and 20.9 kDa and molecular weight dispersities ( Đ ) of 1.34 and 1.71, respectively. Hydrolytic degradation of the polymers was analyzed by 1 H NMR and GPC under basic and acidic conditions. The reversible covalent attachment of these polymers to lysozyme, as well as the hydrolytic and reductive cleavage of the polymer from the protein, was analyzed by gel electrophoresis and mass spectrometry. Following reductive cleavage of the polymer, an increase in activity was observed for both conjugates, with the released protein having full activity. This represents a method to prepare PEGylated proteins, where the polymer is readily cleaved from the protein and the main chain of the polymer is degradable. [ABSTRACT FROM AUTHOR]

We show here a one-pot facile preparation of poly(ethylene glycol) (PEG)-modified poly(lactide- co -glycolide) (PLGA) nanoparticles by means of a novel “block copolymer-assisted” emulsification/evaporation method. In the present article, we clarified the effects of preparation conditions and the structural properties of both polymeric modifiers and particle-forming hydrophobic polymers on the properties of the PEG-modified PLGA nanoparticles. We first clarified that the concentration of PLGA, the volume ratio of an organic solvent to a PVA solution, and a stirring rate were major factors affecting the diameter of the nanoparticles. We successfully prepared the nanoparticles, with a diameter of approximately 200 nm under the optimized conditions. The additive amount and the composition of PEG–PLA block copolymers affected the surface charge of the nanoparticles. Finally, we clarified that the compositions and molecular weights of the block copolymers greatly affected the release properties of PEG-modified nanoparticles. [ABSTRACT FROM AUTHOR]

Immobilization of bioanalytes (e.g., protein, lipid membrane, and cells) within a microfludic channel is a useful strategy in diverse biological analysis including biosensor, diagnosis, and biochemical reactions. Such microfluidic systems can offer miniaturized platforms with distinct advantages such as reduced use of samples or reagents and increased resolution. In particular, polymeric microfluidic devices (e.g., polydimethylsiloxane (PDMS)) bound to a substrate have been widely used. However the non-specific adsorption of bioanalytes is serious problem for microfluidic biological assays, especially for dilute samples. To overcome such limitations, a simple and widely applicable microfluidic channels combined with polyethylene glycol (PEG) microwells have been developed. In this review, we summarize the methods and application of PEG microwells with a particular emphasis on integrated microfluidic systems. The assembly between PEG microwell and microchannel enables precise delivery and manipulation of the biosamples, leading to development of miniaturized diagnostic assays, microreactors, and multiple screening platforms for tissue engineering and cell biology. [ABSTRACT FROM AUTHOR]