A supramolecular coacervate hydrogel was synthesized by simply mixing poly(N-vinylpyrrolidone) (PVP) and tannic acid (TA). Resulting super adhesive properties showed adhesion strength of 3.71 MPa on a glass substrate.

Gelatin nanofibers can be used in the development of a biomimicking artificial extra cellular matrix(ECM) for tissue engineering, wound healing dressings and drug release. However, gelatin nanofibers are water soluble and have weak mechanical strength. Two different cross-linking methods for preparing gelatin nanofibers were used to render gelatin nanofibres insoluble: 1) UV radiation for modified gelatin nanofibers by trans-cinnamic acid; and 2) electrospun gelatin nanofibers cross-linked with genipin. A photo cross-linking method was used to examine the effects of ultraviolet (UV) radiation on the modified gelatin nanofiber scaffolds. A modified gelatin solution containing gelatin, trans-cinnamic acid and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) at a molar ratio of 1:3:30 was prepared. The results showed that the degree of modification in gelatin molecules was 14.5 groups per mol. The modified gelatin was dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol at 20%(w/v) and nanofibrous meshes were obtained by electrospinning. After drying, the nanofibrous meshes were exposed to a commercial germicide UV (=254 nm) lamp for different times. The swelling ratio of each nanofibrous mesh was decreased from 195% to 105% with increasing UV exposure time from 1 h to 10 h. A cross-linking agent method was used to evaluate the effects of the cross-linked gelatin nanofiber scaffolds with genipin. The swelling ratios decreased from 725% to 445% with increasing genipin solution concentration from 0.5%(w/ v) to 2%(w/v). The results of the cell culture suggest that cross-linking gelatin nanofibers with 0.5%(w/v) genipin improves the level of cell proliferation with increasing cell culture time from 1 day to 5 days. Moreover, the cell viability of each nanofiber increased with increasing cell culture time. However, the cell viability decreased with increasing genipin solution concentration.

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ABSTRACT:Biodegradable ABA triblock copolymers of L-lactide and trimethylene carbonate with given compositions were prepared and chain-extended to produce high molecular weight polymer. The polymers were semicrystalline, and exhibited well microphase-segregated morphology with one crystalline poly(L-lactide) (PLLA) and the other soft and amorphous poly(trimethylene carbonate) (PTMC) block segments. The polymers could be cast into flexible and tough film, reversibly stretchable with elongation up to about 300%. This material may provide a novel thermoplastic elastomer possessing desirable properties including biodegradability, biocompatibility and good mechanical properties including two-phase morphology. Also a preliminary result on the hydrolytic degradation behavior was discussed.KEY WORDS Poly(L-lactide) (PLLA) / Poly(trimethylene carbonate) (PTMC) / Block Copolymer / Biodegradable / Thermoplastic Elastomer /

The catechol functional group of dopamine (3,4‐dihydroxyphenethylamine) has the ability to form strong adhesive bonds to inorganic and organic surfaces in aqueous environments. In this study, novel adhesive polyaspartamides containing catechol pendant groups were synthesized from polysuccinimide through successive aminolysis reactions with quantitative dopamine and ethylenediamine. The adhesion and crosslinking of dopamine‐modified polyaspartamide in aqueous alkaline media was used successfully to modify the surface of various materials (including synthetic polymers, metals, metal oxides, ceramics) using a simple immersion method. Contact angle measurements, SEM and X‐ray photoelectron spectroscopy of the modified surfaces were used to verify the surface coating on a variety of materials with very different inherent wetting properties. These novel biocompatible polymers have potential industrial and biomedical applications as adhesives or coating materials for functional surface modification. Copyright © 2011 Society of Chemical Industry

We synthesized and evaluated biodegradable and elastomeric polyesters (poly(glycerol sebacate) (PGS)) using polycondensation between glycerol and sebacic acid to form a cross-linked network structure without using exogenous catalysts. Synthesized materials possess good mechanical properties, elasticity, and surface erosion biodegradation behavior. The tensile strength of the PGS was as high as 0.28 ± 0.004 MPa, and Young's modulus was 0.122 ± 0.0003 MPa. Elongation was as high as 237.8 ± 0.64%, and repeated elongation behavior was also observed to at least three times the original length without rupture. The water-in-air contact angles of the PGS surfaces were about 60°. We also analyzed the properties of an electrospray coating of biodegradable PGS on a nitinol stent for the purpose of enhancing long-term patency for the therapeutic treatment of varicose veins disease. The surface morphology and thickness of coating layer could be controlled by adjusting the electrospraying conditions and solution parameters.

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consist of soft collagen with a water con tent of around 60-80%, their unique structural characteristics provide high tensile strength and excellent fatigue resis tance. [1][2][3][4] The high strength of tendons is derived from the hierarchical structure and anisotropy of collagen fibers formed by crosslinking collagen molecules and gathered to form larger bundles. Tendon tobone integration, called enthesis, is another important feature of tendons. The enthesis is the part where the tendon and ligament insert into the bone and transmit the mechanical load from muscle to bone. The enthesis is composed of four zones (pure dense fibrous connective tissue, uncalcified fibrocartilage, calcified fibro cartilage, and bone) exhibiting gradients in tissue organization with varying cellular composition (collagentomineral), which leads to high adhesive, mechanical prop erties between the tendon and bone. [5][6][7][8] The strong mechanical properties of anisotropic, hierarchically aligned collagen fibers in tendons and the unique tendonto bone integration enable an effective transfer of high mechan ical stress. In general, this unique and complex interface and the corresponding mechanical properties of tendon and liga ment are difficult to mimic using biomaterials.Recently, there have been significant advances in hydrogels exhibiting high mechanical properties or adhesive characteris tics which are extensively improved compared to that of con ventional hydrogels. However, most reported hydrogels either have high adhesion but significantly inferior mechanical properties than those of tendons [9][10][11][12][13][14][15][16][17][18][19] or have strong mechanical properties but very weak adhesion. [20][21][22][23][24][25][26][27][28][29][30][31][32][33] Very recent studies have attempted to simultaneously achieve high adhesiveness and excellent mechanical properties of hydrogels for bioad hesion; [34][35][36] nevertheless those hydrogels are far softer than the tendon. Also, most of them have focused on the adhe sion to relatively soft tissues such as heart, skin, cartilage, and tendon; [9][10][11][12][13][14][15][16][17][18][19]35,36] there have been no reports on mechanically enhanced hydrogel with strong adhesion to the bone. This is due to the tradeoff between the high modulus or strength of hydrogel and its adhesiveness; it is hard to achieve high adhe sion of stiff and strong hydrogels to a solid surface.Hence, this study proposes an anisotropic, stiff, and strong hydrogel with a high adhesiveness to the bone, mimicking both the mechanical properties of the tendon and the tendon tobone interface. A tough triple network (TN) hydrogel Tendon consists of soft collagen, yet it is mechanically strong and firmly adhered to the bone owing to its hierarchically anisotropic structure and unique tendon-to-bone integration (enthesis), respectively. Despite the recent advances in biomaterials, hydrogels simultaneously providing tendon-like high mechanical properties and strong adhesion to bone-mimicking enthesis is still challenging....