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    Bioadhesive functional hydrogels: Controlled release of catechol species with antioxidant and antiinflammatory behavior. Puertas-Bartolomé María,Benito-Garzón Lorena,Fung Stephanie,Kohn Joachim,Vázquez-Lasa Blanca,San Román Julio Materials science & engineering. C, Materials for biological applications Chronic wounds are particularly difficult to heal and constitute an important global health care problem. Some key factors that make chronic wounds challenging to heal are attributed to the incessant release of free radicals, which activate the inflammatory system and impair the repair of the wound. Intrinsic characteristics of hydrogels are beneficial for wound healing, but the effective control of free radical levels in the wound and subsequent inflammation is still a challenge. Catechol, the key molecule responsible for the mechanism of adhesion of mussels, has been proven to be an excellent radical scavenger and anti-inflammatory agent. Our approach in this work lies in the preparation of a hybrid system combining the beneficial properties of hydrogels and catechol for its application as a bioactive wound dressing to assist in the treatment of chronic wounds. The hydrogel backbone is obtained through a self-covalent crosslinking between chitosan (Ch) and oxidized hyaluronic acid (HAox) in the presence of a synthetic catechol terpolymer, which is subsequently coordinated to Fe to obtain an interpenetrated polymer network (IPN). The structural analysis, catechol release profiles, in vitro biological behavior and in vivo performance of the IPN are analyzed and compared with the semi-IPN (without Fe) and the Ch/HAox crosslinked hydrogels as controls. Catechol-containing hydrogels present high tissue adhesion strength under wet conditions, support growth, migration and proliferation of hBMSCs, protect cells against oxidative stress damage induce by ROS, and promote down-regulation of the pro-inflammatory cytokine IL-1β. Furthermore, in vivo experiments reveal their biocompatibility and stability, and histological studies indicate normal inflammatory responses and faster vascularization, highlighting the performance of the IPN system. The novel IPN design also allows for the in situ controlled and sustained delivery of catechol. Therefore, the developed IPN is a suitable ECM-mimic platform with high cell affinity and bioactive functionalities that, together with the controlled catechol release, will enhance the tissue regeneration process and has a great potential for its application as wound dressing. 10.1016/j.msec.2019.110040
    One pot preparation of chitosan/hyaluronic acid-based triple network hydrogel via in situ click reaction, metal coordination and polyion complexation in water. Engkagul Visuta,Sereemaspun Amornpun,Chirachanchai Suwabun Carbohydrate polymers Development of biopolymer hydrogels with multiple networks is regarded as a way to obtain gel strengths with bio-related properties. The present work, for the first time, demonstrates preparation of one pot triple network hydrogel of chitosan (CS) and hyaluronic acid (HA) (HA-triazole/CS-Cu(II) gel), formed by triazole linkage, metal-coordination, and CS-HA polyion complexation. The salt containing water system favors polyion complex formation of CS and HA without precipitation. HA functionalized with alkyne and azide groups in aqueous EDC/NHS allows crosslinking of HA via triazole linkage using Cu(I) azide-alkyne Click chemistry (CuAAC). The required Cu(I) catalyst is generated from Cu(II) in the CS-Cu complex upon addition of sodium ascorbate. The CS/NHS system leads to the solubilization of CS, thus enabling ionic gelation. The mechanical properties and morphologies can be controlled by simply varying the CS-HA mole ratios. In addition, the CS-HA triple-network (TN) hydrogels show biocompatibility based on studies with chondrocyte cells. 10.1016/j.carbpol.2018.07.090
    In situ antibody-loaded hydrogel for intravitreal delivery. Awwad Sahar,Abubakre Abdullah,Angkawinitwong Ukrit,Khaw Peng T,Brocchini Steve European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences Therapeutic protein medicines have transformed the treatment of blinding diseases (e.g. age-related macular degeneration, AMD) during the last 1-2 decades. Many blinding conditions such as AMD are chronic; and require multiple intravitreal injections over a long period to achieve a high and reproducible dose needed for clinical benefit. Prolonging the duration of action of ophthalmic drugs is critical to reduce the frequency of injections. Thermoresponsive hydrogels (e.g. N-isopropylacrylamide, NIPAAM) that collapse in physiological conditions can entrap and sustain the release of a therapeutic protein. However, most NIPAAM hydrogels are not biodegradable and often requires invasive surgery to remove the depot. Here, we report the preparation of a hydrogel derived from NIPAAM and acrylated hyaluronic acid (Ac-HA) as a biodegradable, macromolecular crosslinker. Ac-HA was prepared by the acrylation of hyaluronic acid (HA). Antibody (infliximab (INF), 5.0 mg/mL or bevacizumab (BEVA), 12.5 mg/mL), NIPAAM (0.35 mmol) and Ac-HA (2.0-10.0 mg/mL, 40.0-200.0 nmol) were first mixed prior to redox polymerisation to ensure maximal protein mixing and to shorten the burst release. Hydrogels with lower amounts of Ac-HA (2.0-4.0 mg/mL, 40.0-80.0 nmol) showed favourable lower critical solution temperature (LCST) values and injectability (27-29G) than higher amounts of Ac-HA (>4.0 mg/mL, >80.0 nmol). These hydrogels were further characterised (swelling ratio (SR), water retention (WR) and rheology). All hydrogels degraded in presence of bovine testes hyaluronidase (0-50 U/mL, 37 °C, 100 rpm). Release studies of BEVA-loaded hydrogels were investigated in vitro using the PK-Eye™ model, which estimates the human clearance times of proteins from the back of the eye. Phosphate buffered saline (PBS, pH 7.4, 37 °C) was used rather than simulated vitreous to more effectively map trends between the formulations. A zero-order release profile was observed between days 5 to 50 with 43.3 ± 9.5% protein released at day 50. Determining protein binding and functionality from a formulation is crucial to determine the optimal formulation prior to more detailed studies that might be necessary. BEVA showed binding to human vascular growth endothelial factor (VEGF) throughout the study (two months) while still maintaining a therapeutic dose (123.5 ± 45.6 ng) in the posterior cavity of the PK-Eye™ model. These encouraging results suggest that extended release of proteins in the vitreous can be achieved using injectable hydrogels derived from NIPAAM and HA. 10.1016/j.ejps.2019.104993
    Thiol-Mediated Synthesis of Hyaluronic Acid-Epigallocatechin-3-O-Gallate Conjugates for the Formation of Injectable Hydrogels with Free Radical Scavenging Property and Degradation Resistance. Liu Chixuan,Bae Ki Hyun,Yamashita Atsushi,Chung Joo Eun,Kurisawa Motoichi Biomacromolecules Hyaluronic acid (HA)-based biomaterials have demonstrated only limited in vivo stability as a result of rapid degradation by hyaluronidase and reactive oxidative species. The green tea catechin, (-)-epigallocatechin-3-O-gallate (EGCG), has received considerable attention because of its powerful antioxidant and enzyme-inhibitory activities. We describe here the synthesis of HA-EGCG conjugate using a thiol-mediated reaction and its use for the preparation of a long-lasting injectable hydrogel. HA-EGCG conjugates with tunable degrees of substitution were synthesized by the nucleophilic addition reaction between EGCG quinone and thiolated HA under mild conditions. Contrary to unmodified HA, the conjugates exhibited free radical scavenging and hyaluronidase-inhibitory activities. Peroxidase-catalyzed coupling reaction between EGCG moieties was employed to produce in situ forming HA-EGCG hydrogel with surprisingly high resistance to hyaluronidase-mediated degradation. When injected subcutaneously in mice, HA-EGCG hydrogel was retained much longer than HA-tyramine hydrogel with minimal inflammation. 10.1021/acs.biomac.7b00788
    Synthesis and characterization of hyaluronic acid hydrogels crosslinked using a solvent-free process for potential biomedical applications. Larrañeta Eneko,Henry Megan,Irwin Nicola J,Trotter Johann,Perminova Anastasia A,Donnelly Ryan F Carbohydrate polymers Hyaluronic acid (HA) is a natural linear polysaccharide that has been used extensively in the biomedical field as it is a biocompatible, biodegradable, nontoxic and non-immunogenic polymer with high water affinity. Besides, the presence of multiple acid and hydroxyl groups in the HA molecule makes it an ideal candidate for chemical modification. The present paper describes the synthesis and characterization of HA-based hydrogels. For this purpose, aqueous mixtures containing 5% (w/w) of HA and different concentrations of Gantrez S97 (GAN) (1, 3 and 5% w/w) were used to prepare HA-based hydrogels. The mixtures were dried and the hydrogels were obtained after heating the solid material at 80°C for 24h. GAN is the acid form of an methylvinylether and maleic anhydride copolymer and contains multiple acid groups that can form ester bonds when reacting with the multiple hydroxyl groups present in HA chains. The method described here present potential to be applied for the preparation of HA-based biomaterials with a defined form as the crosslinking reaction between HA and the crosslinker takes place in solid phase. Besides, the method can be considered an environmental-friendly process as no organic solvents or potentially toxic substances were used. The esterification reaction was confirmed by infrared spectroscopy and dynamic scanning calorimetry measurements. The loading and release capabilities of the hydrogels were evaluating by using methylene blue (MB) as a model molecule. The hydrogels showed a high affinity for MB showing loadings up to 0.35mg MB per mg of hydrogel. Moreover, the hydrogels were capable of sustaining the MB release over two days. The use of microwave radiation was evaluated to reduce the crosslinking time from 24h to 1h, but this procedure needs to be optimized in future studies. As the crosslinking procedure takes place in solid state, the HA/GAN hydrogels were used to prepare micro-engineered device, microneedle arrays. Finally, the antimicrobial properties of the hydrogels were evaluated. The results showed that the hydrogels presented anti-infective properties. 10.1016/j.carbpol.2017.12.015
    Preparation and properties of cellulose nanocrystals, gelatin, hyaluronic acid composite hydrogel as wound dressing. Yin Fangqing,Lin Lanfang,Zhan Shijuan Journal of biomaterials science. Polymer edition Gelatin (GA), hyaluronic acid (HA) and cellulose nanocrystals (CNC) are promising materials for skin wound care. In this study the GA-HA-CNC hydrogels were prepared by cross-linking and freeze-drying. The composition and mechanism of GA-HA-CNC hydrogels were confirmed by FTIR. The morphology and pore size were obtained by SEM. We accessed the physical property from rheological results and swelling ratio. NIH-3T3 cells were inoculated into the hydrogels and cultured for different days, then we analyzed the cytotoxicity of the prepared hydrogels by CCK-8 methods and live/dead pictorial diagram using staining kits. FTIR revealed the combination between GA, HA and CNC was attributed to the amide bond and hydrogen bonding. SEM results showed that the drying GA-HA-CNC hydrogels were spongy, with the pore diameter about 80-120 µm. CNC significantly enhanced the property of the hydrogels and play a vital role according to the rheology and swelling results. The cells culture results showed that NIH-3T3 cells can attached to, grow, and proliferate well on the GA-HA-CNC hydrogels. In conclusion, the natural GA-HA-CNC hydrogel has great potential for the skin wound repair. 10.1080/09205063.2018.1558933
    In situ formed collagen-hyaluronic acid hydrogel as biomimetic dressing for promoting spontaneous wound healing. Ying Huiyan,Zhou Juan,Wang Mingyu,Su Dandan,Ma Qiaoqiao,Lv Guozhong,Chen Jinghua Materials science & engineering. C, Materials for biological applications Wound dressing is distinctly important to wound healing, because it can not only protect wound from external disturbance, but also provide an ideal environment for wound closure. However, most of wound dressings need additional active ingredients to assist the repair process. In order to develop new dressings that can present spontaneous healing activity, herein, an injectable hydrogel consisted of collagen I and hyaluronic acid has been designed to mimic extracellular matrix for vascular cells growing and wound closure. The preparation of hydrogel (COL-HA) was realized through in situ coupling of phenol moieties of collagen I-hydroxybenzoic acid (COL-P) and hyaluronic-acid-tyramine (HA-Tyr) through horseradish peroxidase (HRP). The physical structure and properties were characterized, and the biological performances were analyzed. COL-HA hydrogel presented porous structure that contributed to the exchange of gas, medium and nutrition. Human microvascular endothelial cells (HMEC) and fibroblasts (COS-7) cultured within this hydrogel showed significant proliferation behaviors. More importantly, a certain level of vascular endothelial growth factor (VEGF) was observed in HMEC cultured hydrogel, which led to the possibility of vascular regeneration. For the full-thickness wound, the healing ratio and validity of wound treated with COL-HA hydrogel were higher than commercial drug and individual COL-P hydrogel, HA-Tyr hydrogel groups, since collagen and hyaluronic acid made joint efforts to improve wound repair. 10.1016/j.msec.2019.03.093
    A fully degradable and photocrosslinked polysaccharide-polyphosphate hydrogel for tissue engineering. Hao Ying,He Jinlin,Ma Xun,Feng Lin,Zhu Mo,Zhai Yuanxin,Liu Yang,Ni Peihong,Cheng Guosheng Carbohydrate polymers Extracellular matrix degradability meditates cell behaviors and gains increasing importance in the development of implantation materials for tissue engineering. Here, we developed a fully biodegradable hydrogel combining the unique features of synthetic polyphosphate polymer and natural polysaccharide polymer. Polyphosphate copolymer poly(butynyl phospholane)-random-poly(ethylethylene phosphate) (PBYP-r-PEEP) bearing pendent alkynes was synthesized through a facile one-pot reaction. Subsequently, thiol-yne "click" reaction was employed to fabricate the fully degradable and photocrosslinked hydrogel by mixing PBYP-r-PEEP with thiolated biodegradable hyaluronic acid (HA-SH). The generated HA/PPE hydrogels show viscoelastic properties and enzymatic biodegradability, supporting the growth of human mesenchymal stem cells (hMSCs). HA/PPE hydrogel is permissive to the covalent conjugation of cell-adhesive peptide RGD, which can enhance the cell-cell interactions. This HA/PPE hydrogel system provides a fully biodegradable platform that can support hMSCs growth and facilitate the formation of cell clustering, expanding the range of fully degradable materials for tissue engineering and regenerative medicine. 10.1016/j.carbpol.2019.115257
    Hyaluronic Acid-Based Activatable Nanomaterials for Stimuli-Responsive Imaging and Therapeutics: Beyond CD44-Mediated Drug Delivery. Choi Ki Young,Han Hwa Seung,Lee Eun Sook,Shin Jung Min,Almquist Benjamin D,Lee Doo Sung,Park Jae Hyung Advanced materials (Deerfield Beach, Fla.) There is a rapidly increasing interest in developing stimuli-responsive nanomaterials for treating a variety of diseases. By enabling the activation of function locally at the sites of interest, it is possible to increase therapeutic efficacy significantly while simultaneously reducing adverse side effects. While there are many sophisticated nanomaterials available, they are often highly complex and not easily transferrable to industrial scales and clinical settings. However, nanomaterials based on hyaluronic acid offer a compelling strategy for reducing their complexity while retaining several desirable benefits such as active targeting and stimuli-responsive degradation. Herein, the basic properties of hyaluronic acid, its binding partners, and natural routes for degradation by hyaluronidases-hyaluronic-acid-degrading enzymes-and oxidative stresses are discussed. Recent advances in designing hyaluronic acid-based, actively targeted, hyaluronidase- or reactive-oxygen-species-responsive nanomaterials for both diagnostic imaging and therapeutic delivery, which go beyond merely the classical targeting of CD44, are summarized. 10.1002/adma.201803549