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The growing demand for drug carriers and green-technology-based tissue engineering materials has enabled the fabrication of different types of micro- and nano-assemblies. Hydrogels are a type of material that have been extensively investigated in recent decades. Their physical and chemical properties, such as hydrophilicity, resemblance to living systems, swelling ability and modifiability, make them suitable to be exploited for many pharmaceutical and bioengineering applications. This review deals with a brief account of green-manufactured hydrogels, their characteristics, preparations, importance in the field of green biomedical technology and their future perspectives. Only hydrogels based on biopolymers, and primarily on polysaccharides, are considered. Particular attention is given to the processes of extracting such biopolymers from natural sources and the various emerging problems for their processing, such as solubility. Hydrogels are catalogued according to the main biopolymer on which they are based and, for each type, the chemical reactions and the processes that enable their assembly are identified. The economic and environmental sustainability of these processes are commented on. The possibility of large-scale processing in the production of the investigated hydrogels are framed in the context of an economy aimed at waste reduction and resource recycling., Competing Interests: The authors declare no conflicts of interest.

Aim: The work's aim was the preparation and characterization of a hydrogel based on gelatin and glycerine, useful for site-specific release of benzydamine, an anti-inflammatory drug, able to attenuate the inflammatory process typical of the vaginal infection., Objective: The obtained hydrogel has been characterized by Electronic Scanning Microscopy (SEM) and Differential Scanning Calorimetry (DSC). In addition, due to the precursor properties, the hydrogel exhibits a relevant mucoadhesive activity., Methods: The swelling degree was evaluated at two different pHs and at defined time intervals. In particular, phosphate buffers were used at pH 6.6, in order to mimic the typical conditions of infectious diseases at the vaginal level, particularly for HIV-seropositive pregnant women, and pH 4.6, to simulate the physiological environment., Results: The obtained results revealed that the hydrogel swells up well at both pHs., Conclusion: Release studies conducted at both pathological and physiological pHs have shown that benzydamine is released at the level of the vaginal mucosa in a slow and gradual manner. These data support the hypothesis of the hydrogel use for the site-specific release of benzydamine in the vaginal mucosa., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

pH-sensitive bovine serum albumin (BSA) hydrophilic microspheres were prepared by free radical polymerization of methacrylate derivatized BSA and methacrylic acid sodium salt. Incorporation of both monomers in hydrogels was confirmed by Fourier transform infrared spectroscopy. Morphological analysis by scanning electron microscopy showed spherical shape and porous surface of all prepared samples. The microspheres showed high water affinity at neutral pH values and a narrow dimensional distribution. Network density of hydrogels depends on derivatization degree (DD%) of BSA and/or concentration of modified BSA in the polymerization feed. In order to employ the prepared samples such as pH-sensitive hydrogels, in vitro release studies, in media simulating biological fluids, were performed using diflunisal (DF) and beta-propranolol (PR) as model drugs. Experimental data showed that the release profiles depend on drug-matrix interactions and diffusional limitation awardable to crosslinking degree of microparticles. beta-Propranolol is quickly released at pH 1.0 and a complete release after 1 h at pH 6.8 was observed. In the case of diflunisal pH-sensitive release was observed. At pH 1.0 low amounts of drug were released (w/w<10% after 2 h). When the pH is 6.8, the diflunisal release increased in the amount (w/w>75% after 24 h).

Graphical abstract Highlights • Xanthan gum-based omega-3 PUFA-containing hydrogels and microspheres were prepared. • The materials were characterized for size, swelling degree and loading efficiency. • The xanthan gum-based materials showed antioxidant efficacy in vitro. • Omega-3 PUFAs inhibited more efficiently colorectal cancer cell growth when enclosed. • Enclosed omega-3 PUFAs powerfully inhibited colorectal cancer cell proliferation. Abstract Xanthan gum-based microspheres and hydrogels, useful for targeted colorectal release of omega-3 polyunsaturated fatty acids (PUFAs), were successfully prepared and characterized. In particular, the microsphere size, as well as the high hydrogel swelling degree at pH 7.4, and the omega-3 PUFA loading efficiency of both the materials suggested their suitability for colorectal delivery. Moreover, the antioxidant efficiency of the xanthan gum based materials suggests their ability to protect the omega-PUFA cargo. We demonstrated that α-linolenic acid (ALA 18:3ω-3) carried by the materials increased significantly its ability to reduce colorectal cancer cell growth in vitro. On the contrary, docosahexaenoic acid (DHA, 22:6ω-3) enclosed in the hydrogel formulation did not enhance its already high anti-neoplastic potential. The improved anti-neoplastic efficacy of ALA enclosed in both the xanthan gum-based formulations further supports the hypothesis of a potential use of this omega-3 PUFA as a suitable and more sustainable alternative to the fish-derived DHA. [ABSTRACT FROM AUTHOR]

ABSTRACT The purpose of this work is the preparation of trehalose hydrogel for dermatological applications, particularly, for skin burn treatment. Trehalose is a disaccharide compound containing hydroxyl groups in its structure susceptible to derivatization. The obtained hydrogel was loaded once with hyaluronic acid, a fundamental component of connective tissue, and again with silver nitrate, an ingredient with antibacterial properties. The trehalose hydrogel was characterized by FTIR spectrometry and 1H-NMR. The hydrogel swelling characteristics and release studies of entrapped hyaluronic acid or silver nitrate were evaluated at two pH values: pH 4.5 mimicking physiological conditions and pH 6.5 simulating the burned skin condition. The antioxidant activity of not loaded hydrogel in inhibiting the lipid peroxidation was performed in rat-liver microsomal membranes, induced in vitro by tert-butyl hydroperoxide ( tert-BOOH). The results confirm the possibility that the trehalose hydrogel can find use in the treatment of various skin lesions, particularly in burn therapy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44755. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, we report the synthesis of cellulose hydrogel containing ferulic moieties and the evaluation of its antioxidant and scavenger activity. Acrylic groups were inserted onto cellulose backbone by a heterogeneous synthesis to produce two cellulose monomers with different degree of substitution (DS). The radical copolymerization of acrylcellulose (AcrC) with N,N-dimethylacrylamide (DMAA) was carried out in NH3/Urea aqueous solution, in a range of composition between 24 and 60wt% of AcrC. The obtained hydrogels were characterized by infrared spectroscopy (FT-IR). Their equilibrium swelling degree (α%) was evaluated. They showed good swelling behavior in simulating gastric, intracellular and intestinal fluids and no more different at various pH. The ferulic moieties were directly grafted on the free hydroxylic groups of cellulose hydrogel by acylation, using dicyclohexylcarbodiimide (DCC) and 4-hydroxybenzotriazole (HBT) as condensation agents. Finally, the antioxidant activity in inhibiting the lipid peroxidation, in rat-liver microsomal membranes, induced in vitro by two different sources of free radicals, 2,2′-azobis (2-amidinopropane) (AAPH) and tert-butyl hydroperoxide (tert-BOOH), was evaluated. The effects of scavenging DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals were also investigated. Hydrogel was found to be very efficient scavengers of DPPH radicals. The results strongly suggested that the antioxidant hydrogel neutralize free radicals. This biomaterial could be successfully applied in pharmaceutical field both as prodrug of trans-ferulic acid than as carrier for photo and thermo-degradable drugs to improve their stability. [Copyright &y& Elsevier]

Cardiac regeneration aims to reconstruct the heart contractile mass, preventing the organ from a progressive functional deterioration, by delivering pro-regenerative cells, drugs, or growth factors to the site of injury. In recent years, scientific research focused the attention on tissue engineering for the regeneration of cardiac infarct tissue, and biomaterials able to anatomically and physiologically adapt to the heart muscle have been proposed as valuable tools for this purpose, providing the cells with the stimuli necessary to initiate a complete regenerative process. An ideal biomaterial for cardiac tissue regeneration should have a positive influence on the biomechanical, biochemical, and biological properties of tissues and cells; perfectly reflect the morphology and functionality of the native myocardium; and be mechanically stable, with a suitable thickness. Among others, engineered hydrogels, three-dimensional polymeric systems made from synthetic and natural biomaterials, have attracted much interest for cardiac post-infarction therapy. In addition, biocompatible nanosystems, and polymeric nanoparticles in particular, have been explored in preclinical studies as drug delivery and tissue engineering platforms for the treatment of cardiovascular diseases. This review focused on the most employed natural and synthetic biomaterials in cardiac regeneration, paying particular attention to the contribution of Italian research groups in this field, the fabrication techniques, and the current status of the clinical trials. [ABSTRACT FROM AUTHOR]

Hydrogels have received growing attention in recent years as materials for drug delivery systems (DDS), because they are biocompatible and nontoxic. The drug release from hydrogel formulation containing nanoparticles based on QA-Ch or QA-Ch-S-pro was virtually equal, whereas the hydrogel formulation containing nanoparticle based on SB-Ch was significantly slower. 7 Cardia M.C., Carta A.R., Caboni P., Maccioni A.M., Erbì S., Boi L., Meloni M.C., Lai F., Sinico C. Trimethyl Chitosan Hydrogel Nanoparticles for Progesterone Delivery in Neurodegenerative Disorders. [Extracted from the article]

Hyaluronic acid (HA) is a natural, linear, endogenous polysaccharide that plays important physiological and biological roles in the human body. Nowadays, among biopolymers, HA is emerging as an appealing starting material for hydrogels design due to its biocompatibility, native biofunctionality, biodegradability, non-immunogenicity, and versatility. Since HA is not able to form gels alone, chemical modifications, covalent crosslinking, and gelling agents are always needed in order to obtain HA-based hydrogels. Therefore, in the last decade, different strategies for the design of physical and chemical HA hydrogels have been developed, such as click chemistry reactions, enzymatic and disulfide crosslinking, supramolecular assembly via inclusion complexation, and so on. HA-based hydrogels turn out to be versatile platforms, ranging from static to smart and stimuli-responsive systems, and for these reasons, they are widely investigated for biomedical applications like drug delivery, tissue engineering, regenerative medicine, cell therapy, and diagnostics. Furthermore, the overexpression of HA receptors on various tumor cells makes these platforms promising drug delivery systems for targeted cancer therapy. The aim of the present review is to highlight and discuss recent advances made in the last years on the design of chemical and physical HA-based hydrogels and their application for biomedical purposes, in particular, drug delivery. Notable attention is given to HA hydrogel-based drug delivery systems for targeted therapy of cancer and osteoarthritis. [ABSTRACT FROM AUTHOR]