Polyethylene Glycol Propionaldehyde Research Articles

Injectable Click Chemistry-based Bioadhesives for Accelerated Wound Closure

Tissue adhesives play a vital role in surgical processes as a substitute for sutures in wound closure. However, several existing tissue adhesives suffer from cell toxicity, weak tissue-adhesive strength, and high cost. In this study, by taking advantage of the fast and specific inverse-demand Diels-Alder cycloaddition reaction, a series of bioadhesives were produced by employing copper-free click chemistry pair trans-cyclooctene (TCO) /tetrazine (Tz) in chitosan. The gelation time of the bioadhesives can be optimized to be less than 2 minutes, which meets the need for surgical wound closure in practice. By adding 4-arm polyethylene glycol propionaldehyde (PEG-PALD) as a co-crosslinker, the adhesive strength of the bioadhesives was optimized to be 2.3 times higher than that of the conventional fibrin glue. Moreover, by adjusting the amount of the co-crosslinker, the swelling ratio and pore size of the chitosan bioadhesives can be tuned to fit the need of drug encapsulation and cell seeding. The chitosan bioadhesives possess no significant in vitro cytotoxicity. Using a mice skin incision wound model, we found that the chitosan bioadhesives were able to close the wound faster and promote wound healing process than the fibrin glue. In conclusion, our results support that the innovative click-chemistry based bioadhesives have been developed with improved physical and biological properties for surgical wound closures. Statement of SignificanceThe manuscript describes a new group of click chemistry-based chitosan bioadhesives fabricated by reacting copper-free click chemistry pair trans-cyclooctene/tetrazine with co-crosslinker PEG-PALD. The new bioadhesives possess the properties of simple preparation, injectability, fast gelation, a minimal cytotoxicity, strong adhesive strength to tissue, and enhanced wound healing responses. This innovative strategy may draw interests of readers from the field of biomaterials, drug delivery, surgical device, and translational medicine.

Injectable Click Chemistry-Based Bioadhesives for Accelerated Wound Closure

Tissue adhesives play a vital role in surgical process as a substitution of sutures for wound closure. However, most currently existing tissue adhesives suffer cell toxicity, weak adhesive strength to tissue, and costly. Herein, by taking advantage of the fast and specific inverse-demand Diels-Alder cycloaddition reaction, a series of bioadhesive were produced by employing copper-free click chemistry pair trans-cyclooctene (TCO) /tetrazine (Tz) in the chitosan. The gelation time of the bioadhesives can be optimized to be less than 2 minutes, which meets the need for surgical wound closure in practice. With the adding of 4-arm polyethylene glycol propionaldehyde (PEG-PALD) as a co-crosslinker, the adhesive strength of the bioadhesives is optimized to be 2.7 times higher than that of the conventional fibrin glue. Moreover, by adjusting the amount of the co-crosslinker, the swelling ratio and pore size of the chitosan bioadhesives can be tuned to fit the need of drug encapsulation and cell seeding. The chitosan bioadhesives possess excellent in vitro cytocompatibility. Through a mice skin incision wound model, we proved that the chitosan bioadhesives was able to close the wound faster and promote wound healing process faster than the fibrin glue. In conclusion, our results support that the innovative click-chemistry based bioadhesives have been developed with improved physical and biological properties for surgical wound closures.

The Role of Polyethylene Glycol Size in Chemical Spectra, Cytotoxicity, and Release of PEGylated Nanoliposomal Cisplatin.

This study aimed to synthesize methoxy polyethylene glycol propionaldehyde (mPEG20,000-ALD) for the preparation of PEGylated nanoliposomal cisplatin. Nanocarriers such as liposomes are developed for a wide range of drug delivery systems. PEG with high molecular weight (Mw) is used to coat the liposomes. In this study, simulated Fourier transform infrared (FTIR) spectra of mPEG-ALD were obtained using density functional theory (DFT) calculations and then compared with actual FTIR spectrum of mPEG20,000-ALD (Mw = 20 kDa). We found that the intensity of C = O stretching vibration at 1,700 cm-1 related to the carbonyl functional group of mPEG20,000-ALD was very weak. The results of DFT calculations of mPEG-ALD showed that by increasing the Mw of mPEG-ALD, the intensity of C = O stretching vibration related to the carbonyl functional group of mPEG-ALD was decreased, so we concluded the hypothesis of decreasing the intensity of C = O stretching vibration at 1,700 cm-1 as a result of increasing the Mw of mPEG-ALD. In vitro release of cisplatin showed that the percentages of released cisplatin from PEGylated nanoliposomal cisplatin and free cisplatin were determined to be 46 ± 2% and 97 ± 3% after 35 h, respectively. Cytotoxicity of free cisplatin and PEGylated nanoliposomal cisplatin was evaluated and related half-maximal inhibitory concentration on human ovarian cancer cell line A2780CP was obtained to be 76.6 ± 3.1 and 46.6 ± 2.3 μg/mL, respectively.

Preparation of a monoPEGylated derivative of cyanovirin-N and its virucidal effect on acyclovir-resistant strains of herpes simplex virus type 1.

The long-term administration of acyclovir (ACV) for therapy against herpes simplex virus type 1 (HSV-1) infections can result in the emergence of ACV-resistant HSV strains. It is therefore urgent to develop new anti-herpetic compounds with mechanisms that differ from that of ACV. Cyanovirin-N (CV-N) is an antiviral agent that has an inhibitory effect on HSV-1 infections, and PEGylation of CV-N is potentially useful for pharmaceutical applications. Here, a (Gly4Ser)3 linker molecule was attached to the N-terminus of CV-N, and the resulting compound, linker-CV-N (LCV-N), was produced on a pilot scale with purity up to 95%. Then, PEG10k-LCV-N was synthesized by modifying at the α-amine group of the N-terminus of LCV-N with 10-kDa polyethylene glycol propionaldehyde (mPEG-ALD). CV-N, LCV-N and PEG10k-LCV-N were all found to have potent inhibitory activity against ACV-resistant HSV strains with IC50 values in the nM range. LCV-N was the most potent of these three compounds against both normal and ACV-resistant HSV strains. Although PEG10k-LCV-N showed less antiviral activity than CV-N and LCV-N, it still exhibited significant and universal virucidal activity against drug-resistant viruses. The toxicity and immunogenicity of PEG10k-LCV-N were dramatically lower than those of CV-N and LCV-N. In conclusion, we suggest that LCV-N and PEG10k-LCV-N are promising and safe microbicides for the control and/or treatment of ACV-resistant HSV infection.

Long-lasting hypoglycemic effect of modified FGF-21 analog with polyethylene glycol in type 1 diabetic mice and its systematic toxicity

Fibroblast growth factor-21 (FGF-21) is a novel metabolic regulator and has the potential to become a powerful therapy to treat diabetes mellitus. However, we found that the clinical application of wild type FGF-21 was influenced by its low intrinsic bio-stability and poor hypoglycemic potency. In this study, The N-terminus of FGF-21 analog (mFGF-21) was PEGylated in a site-specific manner by 20kD methoxy poly-ethylene glycol-propionaldehyde (mPEG-ALD). PEGylated mFGF-21 was isolated by Capto Q anion exchange chromatography. The properties of PEGylated mFGF-21 including the in vitro bio-stability and biological activity were evaluated. As well as the anti-diabetic effect of PEGylated mFGF-21 were studied in streptozotocin (STZ)-induced type 1 diabetic mice. Results demonstrated that PEGylated mFGF-21 had a similar capacity of stimulating glucose uptake in HepG2 cells with mFGF-21 and PEGylation of mFGF-21 significantly enhanced the anti-protease ability and the long acting anti-diabetic effect in type 1 diabetic mice. Furthermore, the preliminary safety of PEGylated mFGF-21 following subcutaneously injection was assessed using healthy mice by measuring the body weight, histopathology and clinical biochemical parameters, and the results showed no subacute toxicity to major organs or tissues and no significant changes in physiological and biochemical parameters in healthy mice. Taken together, under the premise of remaining the in vitro biological activity of mFGF-21, PEGylation significantly improves the long lasting hypoglycemic effect of mFGF-21 in type 1 diabetic mice. Our valuation shows that PEGylated mFGF-21 is a potential drug for the effective treatment of type 1 diabetes.

Development of Methods for Obtaining Thymosin Beta 4 Analogs as Conjugates Resistant to Degradation in Bloodstream

A method for the production of monocojugates of recombinant human thymosin s4 (rs4) with capronic acid, polysialic acid (PSA) and polyethylene glycol (PEG) has been developed. The acylation reaction was carried out using hexanoic anhydride; syalilation, by butyraldehyde derivative of polysialic acid (14 kDa) and PEGylation, by a PEG propionaldehyde derivative (10 kDa). As a result of multifactorial experiments, the components of the reaction mixtures were identified, and conditions of those reactions were optimized. For each analog, we developed a single-stage RP HPLC purification procedure that enabled to attain the purity of no less than 98%. The peptide mapping results backed up by chromatography-mass spectrometry and electrophoresis demonstrated that the produced Тs4 analogs are monoconjugates in which the initial peptide is modified at the N-terminal serine residue. The produced analogs feature a higher resistance to degradation in the blood plasma as compared to non-modified Тs4, and they can be regarded as promising candidates for further biological testing.

Anti-Angiogenic Effects of a Mutant Endostatin: A New Prospect for Treating Retinal and Choroidal Neovascularization

PurposePathological fundus angiogenesis is a major cause of vision loss in retina diseases. Endostatin, a C-terminal fragment of collagen XVIII, is an endogenous anti-angiogenic protein. The present study aimed to investigate the in vitro and in vivo anti-angiogenic properties of two proteins: an N-terminal H1D/H3D mutant endostatin (M-ES) and a polyethylene glycol propionaldehyde (PEG) covalent M-ES (PEG-M-ES).MethodsM-ES and PEG-M-ES properties were characterized in vitro using a zinc ion binding assay and a stability test. Activity assays, including migration, proliferation, and tube formation assays, were performed with human retinal microvascular endothelial cells (HRMECs) and human umbilical vein endothelial cells (HUVECs). Mouse oxygen-induced retinopathy (OIR) and choroidal neovascularization (CNV) models were used to evaluate in vivo anti-angiogenic effects. In addition, a rabbit model was used to study the retinal pharmacokinetic profile following an intravitreal injection.ResultsThe results indicated that the H1D/H3D mutations of endostatin reduced the zinc binding capacity of M-ES and facilitated PEG covalent binding. PEG-M-ES was more stable and persisted longer in the retina compared with M-ES. The in vitro studies demonstrated that M-ES and PEG-M-ES inhibited HRMEC and HUVEC proliferation, migration, and tube formation more efficiently than ES. In vivo, a single intravitreal injection of M-ES and PEG-M-ES significantly decreased neovascularization in both the OIR and CNV animal models.ConclusionThe present study demonstrated for the first time that PEG-M-ES exhibits a long-term inhibitory effect on neovascularization in vitro and in vivo. These data suggest that PEG-M-ES may represent an innovative therapeutic strategy to prevent fundus neovascularization.

Characterization of potential degradation products in a PEGylating reagent 20 kDa monomethoxy polyethylene glycol propionaldehyde by RP-HPLC, APCI-MS and NMR

Ensuring quality of PEGylating reagents is essential for the successful development and manufacturing of PEGylated biopharmaceuticals. However, little is known about how to maintain and verify the quality of PEG raw materials for PEGylated protein manufacturing. In this study, monomethoxy polyethylene glycol propionaldehyde (mPEG-aldehyde) was subjected to conditions that mimic accelerated stability conditions. Separation of trace-level degradation products in the presence of mPEG-aldehyde was achieved by derivatization with 2,4-dinitrophenylhydrazine (DNPH), followed by reversed phase high performance liquid chromatography with ultraviolet detection (RP-HPLC-UV) at 355nm. Structural characterization by atmospheric pressure chemical ionization mass spectrometry (APCI-MS) identified formaldehyde, acetaldehyde, crotonaldehyde, acrolein, benzaldehyde, and tolualdehyde as major degradation products or process-related impurities. The presence of formaldehyde and acrolein was confirmed by 1H NMR in the forced degraded mPEG-aldehyde samples without derivatization of mPEG-aldehyde. Findings from this study imply that reactive impurities could form as a result of inappropriate mPEG-aldehyde handling or storage. Further, a rapid screening method based on reversed phase HPLC was shown to be an effective screening assay used for routine screening of mPEG-aldehyde to ensure consistent PEGylated protein product quality.

A PEGylation Technology of L-Asparaginase with Monomethoxy Polyethylene Glycol-Propionaldehyde

Polyethylene glycol (PEG) conjugation technology has been successfully applied to improve the performance of protein drugs. In this study, L-asparaginase was N-terminal site-specifically modified by alkylating PEG with monomethoxy polyethylene glycol-propionaldehyde (mPEG-ALD20000). The optimum reaction parameters were determined as pH 5.0, a molar ratio of mPEG-ALD2000 to L-asparaginase of 10:1, a reaction time of 16 h and temperature of 25 degrees C. PEG-L-asparaginase (PEG-L-ASNase) was isolated and purified with consecutive anion-exchange (XK, 16 x 20 cm, Q Sepharose FF) and gel-filtration (Tricorn, 10 x 600 cm, Sephacryl S-300 HR) chromatography, respectively. PEG-L-ASNase retained 43.5% of its activity and the N-terminal amino groups were modified to an extent of 3.67%.

A PEGylation Technology of L-Asparaginase with Monomethoxy Polyethylene Glycol-Propionaldehyde

A PEGylation Technology of L-Asparaginase with Monomethoxy Polyethylene Glycol-Propionaldehyde

Highly Ordered Nanometer‐Scale Chemical and Protein Patterns by Binary Colloidal Crystal Lithography Combined with Plasma Polymerization

AbstractSurfaces with micro‐ and nanometer‐scale patterns have many potential applications, particularly in lifescience. This article reports on a versatile, straightforward, and inexpensive approach for the creation of chemical patterns using fabricated binary colloid crystals, consisting of small and large particles, as masks for the deposition of an amino‐functionalised ultrathin film by plasma polymerization. After removal of the binary colloidal mask, the characterization techniques [scanning electron microscopy (SEM) and atomic force microscopy (AFM)] reveal a surface contrast that depicts an ability of the small particles to allow diffusion of the plasma to the substrate. A plasma‐polymer film is created under the small particles and the region of substrate in direct contact with the large particle remains uncoated. Numerous types of patterns and feature heights can be produced with good fidelity over areas of several cm2 by appropriate tuning of the binary colloid crystal mask morphology and the plasma‐polymer deposition time. Finally, the amine groups of the patterned surface are used for covalent grafting poly(ethylene glycol) propionaldehyde (PEG‐PALD) by reductive amination under conditions of reduced solubility to produce a patterned surface for directed adsorption of protein. AFM investigations show that the proteins are preferentially attached to the nanometer‐scale regions of the pattern without PEG‐PALD.