Glycol Molecules Research Articles

Tunable integration of absorption-membrane-adsorption for efficiently separating low boiling gas mixtures near normal temperature.

Separation of low boiling gas mixtures is widely concerned in process industries. Now their separations heavily rely upon energy-intensive cryogenic processes. Here, we report a pseudo-absorption process for separating low boiling gas mixtures near normal temperature. In this process, absorption-membrane-adsorption is integrated by suspending suitable porous ZIF material in suitable solvent and forming selectively permeable liquid membrane around ZIF particles. Green solvents like water and glycol were used to form ZIF-8 slurry and tune the permeability of liquid membrane surrounding ZIF-8 particles. We found glycol molecules form tighter membrane while water molecules form looser membrane because of the hydrophobicity of ZIF-8. When using mixing solvents composed of glycol and water, the permeability of liquid membrane becomes tunable. It is shown that ZIF-8/water slurry always manifests remarkable higher separation selectivity than solid ZIF-8 and it could be tuned to further enhance the capture of light hydrocarbons by adding suitable quantity of glycol to water. Because of its lower viscosity and higher sorption/desorption rate, tunable ZIF-8/water-glycol slurry could be readily used as liquid absorbent to separate different kinds of low boiling gas mixtures by applying a multistage separation process in one traditional absorption tower, especially for the capture of light hydrocarbons.

Poly(beta-amino ester)-poly(ethylene glycol) micelles for intracellular therapeutic drug delivery

Event Abstract Back to Event Poly(beta-amino ester)-poly(ethylene glycol) micelles for intracellular therapeutic drug delivery James G. Shamul1, Yechan Kang1, Jayoung Kim1 and Jordan J. Green1, 2 1 Johns Hopkins University, Biomedical Engineering, United States 2 Johns Hopkins University and Medicine, Ophthalmology, Oncology, Neurosurgery, and Materials Science and Engineering, United States Introduction: Self-assembled micellar structures have been extensively studied as drug carriers for cancer and other diseases. These micelles, which are generally formulated with amphiphilic block copolymer, allow controlled release of encapsulated drugs[1]. Poly(β-amino ester) (PBAE) is a class of biodegradable polymers that is widely investigated as non-viral vectors for gene and drug delivery[2]. Neutrally charged, hydrophilic poly(ethylene glycol) (PEG) molecules can be coated onto a positive surface of nanoparticles to prevent aggregation and clearance from non-specific adsorption of proteins on the surface[3]. In this study, PEG was end-capped to hydrophobic PBAE polymer to provide amphiphilicity, trigger micellar self-assembly in aqueous solution, and promoted particle stability. Materials and Methods: To synthesize PEG-PBAE, acrylate-terminated hydrophobic PBAE was reacted with PEG molecules to produce PEG-PBAE-PEG amphiphilic copolymers. Gel permeation chromatography and 1H NMR analysis verified successful PEG end-capping. After micellar self-assembly in aqueous solution, the micelles were characterized by measuring the surface charge by dynamic light scattering, size by nanoparticle tracking analysis, and critical micelle concentration (CMC) by pyrene fluorescence. Micellar morphology and aggregation were visualized by TEM. The cellular uptake and cytotoxicity of doxorubicin (dox)-loaded micelles and blank micelles were evaluated in HUH7 human hepatocellular carcinoma cells using comparable free dox concentration for comparison. Results: PEG-PBAE copolymer was determined to have a CMC of .0155mg/mL. Nanosight data suggests micelle stability due to consistent size in water, PBS, 25%, 50%, and 75% v/v FBS-PBS over 24 h with hydrodynamic diameter of approximately 220 nm. Zeta potential of blank micelles was near neutral at -1.88 mV. Loading efficiency of doxorubicin in PEG-PBAE micelles was determined to be 2.1% by mass. Micelles exhibited 80% cellular uptake in Huh7 cells. Approximately 75% of the cells were killed when exposed to dox-loaded micelles or equivalent concentration of free dox. Conclusions: These results indicate that doxorubicin-loaded micelles can be formulated with a novel PEG-PBAE copolymer. PEG-PBAE micelles are stable over time and can successfully deliver drug cargo inside cancer cells and cause mortality The authors acknowledge Samsung Scholarship and NIH 1R01EB016721 for funding, Johns Hopkins Microscope Facility core for TEM, and Wilmer Core Grant (P30-EY001865, Imaging and Microscopy Core Module) for flow cytometry.

Rational design of keratin-based injectable hydrogels for biomedical applications

Event Abstract Back to Event Rational design of keratin-based injectable hydrogels for biomedical applications Najeong Park1, Yunki Lee1, Suji Choi2, Kyung Min Park3, Yu-Shik Hwang2 and Ki Dong Park1 1 Ajou university, Molecular Science and Technology, Korea 2 Kyung Hee University, Maxillofacial Biomedical Engineering and Institute of Oral Biology, Korea 3 Incheon National University, Bioengineering, Korea Introduction: Injectable hydrogel systmes have received a great attention in the biomedical research fields due to the minimally invasiveness as well as the structural similarity to the natural extracellular matrix and multi-tunable properties. Up to date, various kinds of biomaterials have been utilized to create injectable hydrogel matrices for therapeutic implants and therapeutic vesicles[1]. Keratin, derived from hair, has emerged as a fascinating biomaterial due to excellent biocompatibility, biodegradability, low immunogenecity, and favorable cellular interactions. While the natural polymer has been widely used for biomedical applications, poor solubility of keratin in aqueous solutions has been recognized as a critical limitation for use in a broad range of applications including development of injectable biomaterial systems[2]. Herein, we developed keratin-based in situ crosslinkable hydrogels through the enzymatic reaction. We fisrt desinged a water soluble karatin by conjugating poly(ethylene glycol) (PEG) molecules tethered with tyrmine (TA), which can be crosslinked to form the hydrogel network. We next evaluated its physico-chemical and biological properteis, showing a great potential as bioactive injectable materials Materials and Methods: Human hair keratin was extracted by slight modified Shindai method[3]. Keratin-PEG-TA (KPT), a water soluble keratin, was synthesized by conjugating amine-PEG-TA (PEG M.W. = 4,000) to keratin backbone via EDC/NHS chemistry with different PEG feed amount. The chemical structure of the KPT was confirmed using 1H NMR and TGA analysis. The physico-chemical properties of KPT hydrogels were examined, such as gelation time, rheological properties depending on HRP or H2O2 concentrations. In vitro cytocompatibility of hydrogels was also evaluated using human dermal fibroblasts cultured with KPT hydrogel extracts. Results and Discussion: The chemical structures of KPT were confirmed by 1H-NMR and TGA analysis, demonstrating PEG and TA were sucessfully conjugated into keratin. We conjugated PEG as a linker to increase water solubility of keratin and confirmed that 5 wt% of KPT conjugate was quickly (~10 sec) and homogeneously dissolved in distilled water though the same concentration of intact keratin was not completely dissolved even with the vigorous vortexing for 30 min. Figure 1a illustrates the schemetic representation of polymer synthesis and hydrogel formation through HRP-mediated crosslinking reaction, forming a C-C bond or C-O bond between phenol moieties. We also evaluated the physico-chemical properties, such as gelation time (ranged from 2 to 100 sec) and mechanical strength (ranged from 100 to 2400 Pa) of the KPT hydrogels (Figure 1b) depending on concentrations of HRP and H2O2, showing the multi-tunable properties. Futhermore, we carried out in vitro cell study to confirm cytocompatibility of the KPT hydrogels, exhibiting excellent cytocompatibility. Conclusions: We have developed a keratin-based in situ cross-linkable hydrogels. It was demonstrated that water solubility of KPT was significantly increased by introducing PEG molecules between the polymer backbone and TA molecules, and the physico-chemical properties could be controlled easily by varying the concentrations of HRP and H2O2 with excellent cytocompatibility. Taken together, we believe that our Keratin-based hydrogels have a great potential for use as injectable materials for a broad range of biomedical applications, including either therapeutic implnats or therapeutic vesicles. This work was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) grant funded by the Ministry of Science, ICT & Future Planning (2015R1A2A1A14027221)

Smart surface coating of drug nanoparticles with cross-linkable polyethylene glycol for bio-responsive and highly efficient drug delivery.

Many drug molecules can be directly used as nanomedicine without the requirement of any inorganic or organic carriers such as silica and liposome nanostructures. This new type of carrier-free drug nanoparticles (NPs) has great potential in clinical treatment because of its ultra-high drug loading capacity and biodegradability. For practical applications, it is essential for such nanomedicine to possess robust stability and minimal premature release of therapeutic molecules during circulation in the blood stream. To meet this requirement, herein, we develop GSH-responsive and crosslinkable amphiphilic polyethylene glycol (PEG) molecules to modify carrier-free drug NPs. These PEG molecules can be cross-linked on the surface of the NPs to endow them with greater stability and the cross-link is sensitive to intracellular environment for bio-responsive drug release. With this elegant design, our experimental results show that the liberation of DOX from DOX-cross-linked PEG NPs is dramatically slower than that from DOX-non-cross-linked PEG NPs, and the DOX release profile can be controlled by tuning the concentration of the reducing agent to break the cross-link between PEG molecules. More importantly, in vivo studies reveal that the DOX-cross-linked PEG NPs exhibit favorable blood circulation half-life (>4 h) and intense accumulation in tumor areas, enabling effective anti-cancer therapy. We expect this work will provide a powerful strategy for stabilizing carrier-free nanomedicines and pave the way to their successful clinical applications in the future.

Artificial membranes with selective nanochannels for protein transport

Membranes based on poly(styrene-b-4-hydroxystyrene-b-styrene) were prepared with nanochannels for preferential transport of proteins with molecular weight 14.3 kg mol−1and rejection of neutral polyethylene glycol molecules with molecular size of 10 kg mol−1.

Room-temperature mechanochemical synthesis of silver nanoparticle homojunction assemblies for the surface-enhanced Raman scattering substrate

Room-temperature mechanochemical synthesis of Ag/Ag homojunction assemblies giving giant surface electric field enhancement for SERS.

Effect of Temperature, Solvent and Precursor Concentration on Anti-Aggregation of ZnO Nanoparticles Prepared by Polyol Method.

We have investigated the formation mechanism of ZnO microspheres in polyol medium. The synthesis conditions have been varied with respect to temperature, medium and Zn-precursor concentration. The X-ray diffraction (XRD) and Raman spectroscopy result shows that the prepared ZnO nanoparticles are hexagonal wurtzite crystal structure and quite crystalline in nature. High resolution transmission electron microscopy (HRTEM) image indicates that the microsphere consists of aggregated nanoparticles in the range of 6 nm to 15 nm. The samples prepared in ethylene glycol medium shows a characteristic ether bond vibration mode in FTIR and it is additionally confirmed by NMR analysis. Initially, the nanoparticles are self-assembled into loosely packed microsphere and then the particles are densely packed by ether bonds formed between the glycol molecules adsorbed on adjacent particles which then grow as perfect microspheres. The sample prepared in EG medium at 150 °C did not show much aggregation. This study proposes the possible mechanism for the formation of ZnO microsphere.

Short communication - Electrochemical preparation and characterization of magnetic core–shell nanowires for biomedical applications

Magnetic CoNi@Au core–shell nanorods have been electrochemically synthesized, characterized and functionalized to test their inherent cytotoxicity in order to assess their potential use for biomedical applications. The initially electrodeposited CoNi nanorods have been covered with a gold layer by means of galvanic displacement to minimize the nanowires toxicity and their aggregation, and favour the functionalization. The presence of a gold layer on the nanorod surface slightly modifies the magnetic behaviour of the as-deposited nanorods, maintaining their soft-magnetic behaviour and high magnetization of saturation. The complete covering of the nanorods with the gold shell favours a good functionalization with a layer of (11-Mercaptoundecyl)hexa(ethylene glycol) molecules, in order to create a hydrophilic coating to avoid the aggregation of nanorods, keeping them in suspension and give them stability in biological media. The presence of the organic layer incorporated was detected by means of electrochemical probe experiments. A cytotoxicity test of functionalized core–shell nanorods, carried out with adherent HeLa cells, showed that cell viability was higher than 80% for amounts of nanorods up to 10μgmL−1. These results make functionalized nanorods promising vehicles for targeted drug delivery in medicine, which gives a complementary property to the magnetic nanoparticles.

Morphogen Electrochemically Triggered Self-Construction of Polymeric Films Based on Mussel-Inspired Chemistry.

Inspired by the strong chemical adhesion mechanism of mussels, we designed a catechol-based electrochemically triggered self-assembly of films based on ethylene glycol molecules bearing catechol groups on both sides and denoted as bis-catechol molecules. These molecules play the role of morphogens and, in contrast to previously investigated systems, they are also one of the constituents, after reaction, of the film. Unable to interact together, commercially available poly(allylamine hydrochloride) (PAH) chains and bis-catechol molecules are mixed in an aqueous solution and brought in contact with an electrode. By application of defined potential cycles, bis-catechol molecules undergo oxidation leading to molecules bearing "reactive" quinone groups which diffuse toward the solution. In this active state, the quinones react with amino groups of PAH through Michael addition and Schiff's base condensation reaction. The application of cyclic voltammetry (CV) between 0 and 500 mV (vs Ag/AgCl, scan rate of 50 mV/s) of a PAH/bis-catechol solution results in a fast self-construction of a film that reaches a thickness of 40 nm after 60 min. The films present a spiky structure which is attributed to the use of bis-functionalized molecules as one component of the films. XPS measurements show the presence of both PAH and bis-catechol cross-linked together in a covalent way. We show that the amine/catechol ratio is an important parameter which governs the film buildup. For a given amine/catechol ratio, it does exist an optimum CV scan rate leading to a maximum of the film thickness as a function of the scan rate.

Aqueous Synthesis of PEGylated Quantum Dots with Increased Colloidal Stability and Reduced Cytotoxicity.

Ligands used on the surface of colloidal nanoparticles (NPs) have a significant impact on physiochemical properties of NPs and their interaction in biological environments. In this study, we report a one-pot aqueous synthesis of 3-mercaptopropionic acid (MPA)-functionalized CdTe/CdS/ZnS quantum dots (Qdots) in the presence of thiol-terminated methoxy polyethylene glycol (mPEG) molecules as a surface coordinating ligand. The resulting mPEG-Qdots were characterized by using ζ potential, FTIR, thermogravimetric (TG) analysis, and microscale thermophoresis (MST) studies. We investigated the effect of mPEG molecules and their grafting density on the Qdots photophysical properties, colloidal stability, protein binding affinity, and in vitro cellular toxicity. Moreover, cellular binding features of the resulting Qdots were examined by using three-dimensional (3D) tumor-like spheroids, and the results were discussed in detail. Promisingly, mPEG ligands were found to increase colloidal stability of Qdots, reduce adsorption of proteins to the Qdot surface, and mitigate Qdot-induced side effects to a great extent. Flow cytometry and confocal microscopy studies revealed that PEGylated Qdots exhibited distinctive cellular interactions with respect to their mPEG grafting density. As a result, mPEG molecules demonstrated a minimal effect on the ZnS shell deposition and the Qdot fluorescence efficiency at a low mPEG density, whereas they showed pronounced effect on Qdot colloidal stability, protein binding affinity, cytotoxicity, and nonspecific binding at a higher mPEG grafting amount.

Nanofibers for drug delivery - incorporation and release of model molecules, influence of molecular weight and polymer structure.

Nanofibers were prepared from polycaprolactone, polylactide and polyvinyl alcohol using NanospiderTM technology. Polyethylene glycols with molecular weights of 2 000, 6 000, 10 000 and 20 000 g/mol, which can be used to moderate the release profile of incorporated pharmacologically active compounds, served as model molecules. They were terminated by aromatic isocyanate and incorporated into the nanofibers. The release of these molecules into an aqueous environment was investigated. The influences of the molecular length and chemical composition of the nanofibers on the release rate and the amount of released polyethylene glycols were evaluated. Longer molecules released faster, as evidenced by a significantly higher amount of released molecules after 72 hours. However, the influence of the chemical composition of nanofibers was even more distinct – the highest amount of polyethylene glycol molecules released from polyvinyl alcohol nanofibers, the lowest amount from polylactide nanofibers.

Spectroscopic, calorimetric, and catalytic evidences of hydrophobicity on Ti-MCM-41 silylated materials for olefin epoxidations

Hydrophobic Ti-MCM-41 samples prepared by post-synthesis silylation treatment demonstrate to be highly active and selective catalysts in olefins epoxidation by using organic hydroperoxides as oxidizing agents in liquid phase reaction systems. Epoxide yields show important enhancements with increased silylation degrees of the Ti-mesoporous samples. Catalytic studies are combined and correlated with spectroscopic techniques (e.g. XRD, XANES, UV-Visible, 29Si MAS-NMR) and calorimetric measurements to better understand the changes in the surface chemistry of Ti-MCM-41 samples due to the post-synthesis silylation treatment and to ascertain the role of these trimethylsilyl groups incorporated in olefin epoxidation. In such manner, the effect of the organic moieties on solids, and both water and glycol molecules contents on the catalytic activity and selectivity are analyzed in detail. Results show that the hydrophobicity level of the samples is responsible for the decrease in water adsorption and, consequently, the negligible formation of the non-desired glycol during the catalytic process. Thus, catalyst deactivation by glycol poisoning of Ti active sites is greatly diminished, this increasing catalyst stability and leading to practically quantitative production of the corresponding epoxide. The extended use of these hydrophobic Ti-MCM-41 catalysts together with organic hydroperoxides for the highly efficient and selective epoxidation of natural terpenes is also exemplified.

Modulating Mucin Hydration and Lubrication by Deglycosylation and Polyethylene Glycol Binding

A key property of mucin glycoproteins is their exceptional capacity to hydrate and lubricate surfaces. In vivo, mucins assemble into mucus hydrogels that cover the epithelium and protect it from dehydration and shear stress. A better understanding of the origin of these properties could lead to new treatment strategies for patients with poor mucus coverage, defective mucus production, or glycosylation as caused by Sjögren syndrome, dry eye, or in the case of certain bacterial infections. In this work, mucin coatings are used to show that mucin‐associated glycans are essential for the formation of such hydrated and lubricating layers. Native mucins are compared with deglycosylated mucins by analyzing their hydration and it is shown that their lubricative potential in the boundary and mixed lubrication regime is linked to the hydration. The removal of glycans from the mucin results in a 3.5‐fold decrease in hydration and an increase in friction by two orders of magnitude. This loss of function is countered by grafting polyethylene glycol (PEG) molecules to defective mucins through lectin–glycan interactions. This lectin‐PEG conjugation restores hydration and improves lubrication of the partially deglycosylated mucin coatings. Thus, local complementation of defective mucus layers could prove to be a useful new treatment strategy.

Structures of exoglucanase from Clostridium cellulovorans: cellotetraose binding and cleavage.

Exoglucanase/cellobiohydrolase (EC 3.2.1.176) hydrolyzes a β-1,4-glycosidic bond from the reducing end of cellulose and releases cellobiose as the major product. Three complex crystal structures of the glycosyl hydrolase 48 (GH48) cellobiohydrolase S (ExgS) from Clostridium cellulovorans with cellobiose, cellotetraose and triethylene glycol molecules were solved. The product cellobiose occupies subsites +1 and +2 in the open active-site cleft of the enzyme-cellotetraose complex structure, indicating an enzymatic hydrolysis function. Moreover, three triethylene glycol molecules and one pentaethylene glycol molecule are located at active-site subsites -2 to -6 in the structure of the ExgS-triethylene glycol complex shown here. Modelling of glucose into subsite -1 in the active site of the ExgS-cellobiose structure revealed that Glu50 acts as a proton donor and Asp222 plays a nucleophilic role.

Scaling of polymer dynamics at an oil-water interface in regimes dominated by viscous drag and desorption-mediated flights.

Polymers are found near surfaces and interfaces in a wide range of chemical and biological systems, and the structure and dynamics of adsorbed polymer chains have been the subject of intense interest for decades. While polymer structure is often inferred from dynamic measurements in bulk solution, this approach has proven difficult to implement at interfaces, and the understanding of interfacial polymer conformation remains elusive. Here we used single-molecule tracking to study the interfacial diffusion of isolated poly(ethylene glycol) molecules at oil-water interfaces. Compared to diffusion in dilute aqueous solution, which exhibited the expected dependence of the diffusion coefficient (D) upon molecular weight (M) of D ∼ M(-1/2) for a Gaussian chain, the behavior at the interface was approximately D ∼ M(-2/3), suggesting a significantly more expanded polymer conformation, despite the fact that the oil was a poor solvent for the polymer. Interestingly, this scaling remained virtually unchanged over a wide range of oil viscosity, despite the fact that at low viscosities the magnitude of the diffusion coefficient was consistent with expectations based on viscous drag (i.e., Stokes-Einstein diffusion), and for high viscosity oil, the interfacial mobility was much faster than expected and consistent with the type of intermittent hopping transport observed at the solid-liquid interface. The dependence on molecular weight, in both regimes, was consistent with results from both self-consistent field theory and previous Monte Carlo simulations, suggesting that an adsorbed polymer chain adopted a partially swollen (loop-train-tail) interfacial conformation.

Microwave-assisted direct coupling of graphene nanoplatelets with poly ethylene glycol and 4-phenylazophenol molecules for preparing stable-colloidal system

Abstract Herein, microwave-assisted direct coupling of Graphene Nanoplatelets (GNP) with polymers including hydroxyl ( OH) groups such as poly ethylene glycol (PEG) and bio-molecules like 4-phenylazophenol (Azo) are investigated. Among different water-soluble polymers, PEG has received unique consideration due to its biocompatibility. Moreover, Azo-treated GNP can easily employ in long-term solar thermal storage. Thus, an electrophilic addition reaction under microwave irradiation is presented as an efficient procedure to functionalize GNP with Azo and PEG. In order to compare the activities of different catalysts under microwave irradiation, the direct coupling of GNP with Azo and PEG were performed in the presence of ZnCl2, FeCl2, TiCl4 and AlCl3, separately. The use of simple Lewis acids loading provides an electrophilic addition reaction in as little as 30 min, which provide a shortcut and prevent time-consuming and multiple steps approaches. Interestingly, PEG-treated GNP has no cross-linking of the flakes, which this allows the production of more dispersed GNP in aqueous media. Investigation of colloidal stability using particle absorbance measurement showed successful results in terms of stability with very low sediment.

A novel NAD(P)H-dependent carbonyl reductase specifically expressed in the thyroidectomized chicken fatty liver: catalytic properties and crystal structure.

A gene encoding a functionally unknown protein that is specifically expressed in the thyroidectomized chicken fatty liver and has a predicted amino acid sequence similar to that of NAD(P)H-dependent carbonyl reductase was overexpressed in Escherichia coli; its product was purified and characterized. The expressed enzyme was an NAD(P)H-dependent broad substrate specificity carbonyl reductase and was inhibited by arachidonic acid at 1.5 μm. Enzymological characterization indicated that the enzyme could be classified as a cytosolic-type carbonyl reductase. The enzyme's 3D structure was determined using the molecular replacement method at 1.98 Å resolution in the presence of NADPH and ethylene glycol. The asymmetric unit consisted of two subunits, and a noncrystallographic twofold axis generated the functional dimer. The structures of the subunits, A and B, differed from each other. In subunit A, the active site contained an ethylene glycol molecule absent in subunit B. Consequently, Tyr172 in subunit A rotated by 103.7° in comparison with subunit B, which leads to active site closure in subunit A. In Y172A mutant, the Km value for 9,10-phenanthrenequinone (model substrate) was 12.5 times higher than that for the wild-type enzyme, indicating that Tyr172 plays a key role in substrate binding in this carbonyl reductase. Because the Tyr172-containing active site lid structure (Ile164-Gln174) is not conserved in all known carbonyl reductases, our results provide new insights into substrate binding of carbonyl reductase. The catalytic properties and crystal structure revealed that thyroidectomized chicken fatty liver carbonyl reductase is a novel enzyme.

AZ17: a new bispecific drug targeting IL-6 and IL-23 with potential clinical use--improves psoriasis in a human xenograft transplantation model.

Targeting more than one molecule in multifactorial diseases involving several disease mediators may provide improved therapeutic efficacy. Psoriasis is a multifactorial disease in which interleukin (IL)-6 and IL-23 are important disease mediators because they facilitate development of Th17 cells; widely accepted to be associated with psoriasis. To meet the need for new therapeutics, we aimed to create a clinically relevant bispecific drug, by combining the inhibitory properties of anti-IL-6 and anti-IL-23 antibodies, exhibiting high affinity, high stability and the ability to be produced in high yield. The bispecific molecule AZ17 was created by combining high affinity binding domains originating from monoclonal antibodies targeting human IL-6 and IL-23. To allow for high and efficient production, AZ17 was assembled by site-specific bioconjugation from two individual single chain fragment variables that were synthesized separately in Escherichia coli. To improve stability and extend pharmacokinetics, a flexible poly-ethylene glycol molecule was used as linker. In preclinical psoriasis models, AZ17 reduced IL-23-induced ear inflammation and improved psoriasis in a xenograft transplantation model where psoriasis skin is transplanted onto immune-deficient mice. The data presented here suggest AZ17 to be a promising drug candidate in psoriasis and other inflammatory diseases associated with Th17 cell development.

Sulfhydryl-specific PEGylation of phosphotriesterase cysteine mutants for organophosphate detoxification.

The catalytic bioscavenger phosphotriesterase (PTE) is experimentally an effective antidote for organophosphate poisoning. We are interested in the molecular engineering of this enzyme to confer additional functionality, such as improved in vivo longevity. To this aim, we developed PTE cysteine mutants with free sulfhydryls to allow macromolecular attachments to the protein. A library of PTE cysteine mutants were assessed for efficiency in hydrolysing the toxic pesticide metabolite paraoxon, and screened for attachment with a sulfhydryl-reactive small molecule, fluorescein 5-maleimide (F5M), to examine cysteine availability. We established that the newly incorporated cysteines were readily available for labelling, with R90C, E116C and S291C displaying the highest affinity for binding with F5M. Next, we screened for efficiency in attaching a large macromolecule, a 30 000 Da polyethylene glycol (PEG) molecule. Using a solid-phase PEGylation strategy, we found the E116C mutant to be the best single-mutant candidate for attachment with PEG30. Kinetic activity of PEGylated E116C, with paraoxon as substrate, displayed activity approaching that of the unPEGylated wild-type. Our findings demonstrate, for the first time, an efficient cysteine mutation and subsequent method for sulfhydryl-specific macromolecule attachment to PTE.

PEGylated Biopharmaceuticals: Current Experience and Considerations for Nonclinical Development.

PEGylation (the covalent binding of one or more polyethylene glycol molecules to another molecule) is a technology frequently used to improve the half-life and other pharmaceutical or pharmacological properties of proteins, peptides, and aptamers. To date, 11 PEGylated biopharmaceuticals have been approved and there is indication that many more are in nonclinical or clinical development. Adverse effects seen with those in toxicology studies are mostly related to the active part of the drug molecule and not to polyethylene glycol (PEG). In 5 of the 11 approved and 10 of the 17 PEGylated biopharmaceuticals in a 2013 industry survey presented here, cellular vacuolation is histologically observed in toxicology studies in certain organs and tissues. No other effects attributed to PEG alone have been reported. Importantly, vacuolation, which occurs mainly in phagocytes, has not been linked with changes in organ function in these toxicology studies. This article was authored through collaborative efforts of industry toxicologists/nonclinical scientists to address the nonclinical safety of large PEG molecules (>10 kilo Dalton) in PEGylated biopharmaceuticals. The impact of the PEG molecule on overall nonclinical safety assessments of PEGylated biopharmaceuticals is discussed, and toxicological information from a 2013 industry survey on PEGylated biopharmaceuticals under development is summarized. Results will contribute to the database of toxicological information publicly available for PEG and PEGylated biopharmaceuticals.