Synthesis and characterization of PLGA nanoparticle/4-arm-PEG hybrid hydrogels with controlled porous structures DOI https://doi.org/10.1039/C6RA08404D Abstract Controlled porous structures, adjustable surface properties and good mechanical properties are essential for hydrogels in promoting cell adhesion and growth.  In this work, we developed four armed poly(ethylene glycol) (4-arm-PEG) hydrogels crosslinked by poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs).  Branched polyethyleneimine (b-PEI) was employed for aminolysis of PLGA to engineer 300, 530 and 1000 nm NPs with a nitrogen contents of 11.7%, 9.4% and 9.7%.  Hybrid hydrogels were formed by crosslinking amino-packed NPs with polymeric chains of 4-arm-PEG-NHS.  By manipulating the NP and PEG contents as well as the NP sizes, the pore sizes could be tailored from 10–20 μm to 20–40 μm and 100–200 μm, and the maximal compressive strength could be optimized to 0.37 MPa.  Cytotoxicity trials indicated the hydrogels were almost non-toxic and biocompatible.  Cell adhesion evaluation testified higher amino contents and a smaller proportion of PEG led to more cell attachment.  These results demonstrated that this kind of hybrid hydrogel may be a suitable candidate for further biomedical applications in tissue engineering. Related products Abbreviation: 4-arm-PEG-NHS For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com

Journal of Molecular Catalysis B: Enzymatic Volume 111, January 2015, Pages 36-42 Site-directed modification of genetically engineered Proteus sp. lipase K107 variants with a polyethylene glycol derivative Highlights •We report a novel method for site-directed PEGylation of protein. •Linear mPEGs of various sizes were functionalized via dopamine. •PEG derivates were used for site-specific PEGylation of enzyme with a single Cys residue. •The PEGylated enzymes maintained their secondary structures and activities, which was higher in low molecular mass PEG conjugates. •Conjugates with the site of polymer coupling near the catalytic centre were more stable. Abstract The covalent attachment of PEG to target proteins, known as PEGylation, has broad biomedical and biotechnological applications. Particularly, site-specific PEGylation is widely used owing to its unique properties of preserving bioactivity, improving the stability of conjugated proteins, and achieving a high degree of homogeneity. In this work, linear mPEGs of various sizes (MW = 5, 12, and 20 kDa) were functionalized via dopamine and used for site-specific PEGylation of Proteus sp. lipase K107 derivatives with a single Cys residue introduced by site-directed mutagenesis on the solvent-accessible surface of the protein. The specificity of conjugation was verified by SDS-PAGE and MALDI-TOF mass spectrometry, and the secondary structures of the conjugates were verified by circular dichroism. PEGylated enzymes retained their activity, which was higher in low molecular mass PEG conjugates. Importantly, both pH and thermal stability of enzymes were enhanced by PEGylation, especially at basic pH and above room temperature. Moreover, conjugates with the site of polymer coupling near the catalytic centre were more stable. These results demonstrate a novel, efficient method of site-specific protein modification via catechol-functionalized PEG that could potentially be applied to other enzymes. Related products Abbreviation: mPEGs For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com

DOI:10.1021/acs.macromol.9b01654 Shear Modulus Dependence of the Diffusion Coefficient of a Polymer Network Published 10 December 2019 Dynamics of a polymer gel network is described by the theory proposed by Tanaka, Hocker, and Benedek (THB) that gives the diffusion coefficient of a polymer network (D=K+43Gf). Here, K is the osmotic bulk modulus, G is the shear modulus, and f is the friction coefficient between the polymer network and the solvent. Although several experimental studies investigated the dynamics of a polymer gel network, the THB theory has yet to be quantitatively validated. In this study, we quantitatively validate the THB theory by comparing D and G of Tetra-poly(ethylene glycol) gels measured by dynamic light scattering and dynamic viscoelastic measurement. The THB theory well described the linear increase in D with increasing G and gave K and f from the slope and the intercept. The gel network structural parameter dependences of the given K and f were well explained by the scaling laws. These results suggest that the THB theory is almost valid. Related products Abbreviation: Tetra-PEG-MA, Tetra-PEG-SH For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com

ArticleDecember 31, 2015 Preparation of a High-Strength Hydrogel with Slidable and Tunable Potential Functionalization Sites Abstract A hydrogel with tunable potential functionalization sites has been successfully prepared. As potential functionalization sites, (2-hydroxypropyl)-α-CDs (Hy-α-CDs) were introduced into the network of tetrahedron-like poly(ethylene glycol) (tetra-PEG) gel through supramolecular chemistry. In the stage of complexation, poly-pseudo-rotaxane consisting of tetra-PEG macromonomer and Hy-α-CD formed in pregel solution. The dynamic complexation process and the structure of the poly-pseudo-rotaxane were investigated by NMR experiment. In the stage of gelation, some cross-linking reactions were completed through click chemistry. The structures and mechanical properties of the resultant hydrogels were characterized by ATR-FTIR, XPS, SEM, and compression test in detail. The number of Hy-α-CD introduced into the hydrogel is related closely to the structure of the poly-pseudo-rotaxane and can be controlled easily by tuning the feed ratio. Anthracene as an example of function was introduced into the hydrogel through Hy-α-CD to preliminarily demonstrate the validity of the potential functionalization site in the last, and the hydrogel also has the capacity for further diverse functionalization. Related products Abbreviation: Tetrahydroxyl-terminated PEG (THPEG) For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com

Drug Deliv. 2017 Nov;24(1):834-845. doi: 10.1080/10717544.2017.1326540. Preliminary study on fabrication, characterization and synergistic anti-lung cancer effects of self-assembled micelles of covalently conjugated celastrol-polyethylene glycol-ginsenoside Rh2 Abstract The aim of this study was to develop an amphipathic polyethylene glycol (PEG) derivative that was bi-terminally modified with celastrol and ginsenoside Rh2 (Celastrol-PEG-G Rh2). Such derivative was capable of forming novel, celastrol-loaded polymeric micelles (CG-M) for endo/lysosomal delivery and thereby synergistic treatment of lung cancer. Celastrol-PEG-G Rh2 with a yield of 55.6% was first synthesized and characterized. Its critical micellar concentration was 1 × 10-5 M, determined by pyrene entrapment method. CG-M had a small particle size of 121.53 ± 2.35 nm, a narrow polydispersity index of 0.214 ± 0.001 and a moderately negative zeta potential of -23.14 ± 3.15 mV. Celastrol and G Rh2 were rapidly released from CG-M under acidic and enzymatic conditions, but slowly released in normal physiological environments. In cellular studies, the internalization of celastrol and G Rh2 by human non-small cell lung cancer (A549) cells treated with CG-M was 5.8-fold and 1.8-fold higher than that of non-micelle control. Combinational therapy of celastrol and G Rh2 using CG-M exhibited synergistic anticancer activities in cell apoptosis and proliferation assays via rapid drug release within endo/lysosomes. Most importantly, the celastrol in CG-M exhibited a long elimination half-life of 445.3 ± 43.5 min and an improved area under the curve of 645060.8 ± 63640.7 ng/mL/h, that were 1.03-fold and 2.44-fold greater than those of non-micelle control, respectively. These findings suggest that CG-M is a promising vector for precisely releasing anticancer drugs within the tumor cells, and thereby exerts an improved synergistic anti-lung cancer effect. Keywords: Celastrol; anti-lung cancer; drug release; ginsenoside Rh2; micelle. Related products Abbreviation: pNP-PEG-pNP For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com

POSS-modified PEG adhesives for wound closure October 2017 Chinese Journal of Polymer Science (English Edition) 35(10):1231-1242 DOI:10.1007/s10118-017-1958-x Abstract PEG-related adhesives are limited in clinical use because they are easy to swell and cannot support the cell growth. In this study, we produced a series of POSS-modified PEG adhesives with high adhesive strength. Introduction of inorganic hydrophobic POSS units decreased the swelling of the adhesives and enhanced cell adhesion and growth. The in vitro cytotoxicity and in vivo inflammatory response experiments clearly demonstrated that the adhesives were nontoxic and possessed excellent biocompatibility. Compared with the sutured wounds, the adhesive-treated wounds showed an accelerated healing process in wounded skin model of the Bama miniature pig, demonstrating that the POSS-modified PEG adhesive is a promising candidate for wound closure. Related products Abbreviation: 4-arm PEG-OH, 4-arm PEG-NH2 For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com

One-pot synthesis of highly mechanical and redox-degradable polyurethane hydrogels based on tetra-PEG and disulfide/thiol chemistry Article information DOI https://doi.org/10.1039/C6RA04320H Abstract Highly mechanical hydrogels with stimuli degradability are promising scaffold materials for tissue engineering, due to their unique advantage of retaining mechanical strength in use, while being able to be readily removed by external stimuli after use.  However, it has always been a big challenge to integrate both good mechanical properties and stimuli degradability into one single hydrogel.  In this work, a series of tetra-PEG polyurethane hydrogels with tunable redox-degradability and a high compressive fracture strength has been synthesized by a one-pot method.  The good mechanical properties are owed to an extremely uniform network of tetra-PEG, and the redox-degradability is realized using cystamine, which contains a highly DTT-sensitive disulfide bond.  The mechanical strength of the as-prepared hydrogels reaches a megapascal range, and their complete degradation time can be flexibly adjusted from 4 to 22 days by controlling the proportion of cystamine.  With the above properties, these hydrogels are believed to have potential bio-applications. Related products Abbreviation: 4-arm PEG For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com

J Mater Chem B. 2019 Apr 14;7(14):2330-2337.  doi: 10.1039/c8tb02928h.  Epub 2019 Mar 7. Microcapsule-embedded hydrogel patches for ultrasound responsive and enhanced transdermal delivery of diclofenac sodium Abstract Transdermal delivery of diclofenac sodium (DS) has drawn much attention for the advantages of avoiding first-pass metabolism, reduced systemic toxicity and better patient compliance, but the successful translation of reported transdermal drug delivery systems (TDDSs) is still limited by poor skin permeability and uncontrollable drug release.  Herein, we designed and fabricated a novel ultrasound responsive TDDS by embedding DS-loaded polyester microcapsules into a hydrogel patch based on four-armed poly(ethylene glycol).  The rational design endows the microcapsule-embedded hydrogel patch with good biocompatibility, excellent skin-adhesion properties and well-controlled ultrasound responsive release behavior.  More importantly, by employing ultrasound as a simultaneous trigger of drug release and efficient penetration enhancer, the encapsulated drug could be released and pass through the skin barrier rapidly under ultrasound, while without the action of ultrasound, a negligible amount of drug was released and penetrated into the subcutaneous tissues in ex vivo and in vivo transdermal drug release experiments, indicating that improved and controllable transdermal delivery of DS was achieved.  Our work demonstrated that the microcapsule-embedded hydrogel patch may be a promising candidate as an ultrasound responsive and enhanced TDDS of DS for treating diseases such as arthritis and topical soft tissue injuries. Related products Abbreviation: 4-arm-PEG-NHS, 4-arm-PEG-NH2 For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com