Chemical structure of antibiotics determines their release rate from drug-loaded poly(vinyl alcohol)/sodium sulfated alginate nanofibrous wound dressings.

Antibiotics are widely used for treatment of infected wounds; however, their application through a local and controlled release system may cause more effectiveness and fewer side-effects. In this study, we fabricated drug-loaded poly(vinyl alcohol)/sodium sulfated alginate (PVA/SSA) nanofibrous mats incorporating cationic antibiotic drugs, i.e.

Cost-reduction strategy to culture patient derived bladder tumor organoids.

Organoids as self-organized structure derived from stem cells can recapitulate the function of an organ in miniature form which have developed great potential for clinical translation, drug screening and personalized medicine. Nevertheless, the majority of patient-derived organoids (PDOs) are currently being cultured in the basement membrane matrices (BMMs), which are constrained by xenogeneic origin, batch-to-batch variability, cost, and complexity. Besides, organoid culture relies on biochemical signals provided by various growth factors in the composition of medium.

Functional Efficacy of Tissue-Engineered Small-Diameter Nanofibrous Polyurethane Vascular Grafts Surface-Modified by Methacrylated Sulfated Alginate in the Rat Abdominal Aorta.

Improved design to imitate natural vascular scaffolds is critical in vascular tissue engineering (VTE). Smooth muscle cells originating from surrounding tissues require larger pore sizes relative to those of endothelial progenitor cells found in the bloodstream. Furthermore, biofunctionalized scaffolds mimic the microenvironment, cellular function, and tissue morphogenesis.

Degree of sulfation of freeze-dried calcium alginate sulfate scaffolds dramatically influence healing rate of full-thickness diabetic wounds.

Diabetic foot ulcer (DFU) is a chronic and non-healing wound in all age categories with a high prevalence and mortality in the world. An ideal wound dressing for DFU should possess the ability of adsorbing high contents of exudate and actively promote wound healing. Here, we introduced the calcium alginate sulfate as a new biomaterial appropriate for use in wound dressing to promote the healing of full-thickness ulcers in a diabetic mouse model.

Enhancing cell activities through integration of polyanionic alginate or hyaluronic acid derivatives with triboelectric nanogenerators.

The impact of electrical stimulation has been widely investigated on the wound healing process; however, its practicality is still challenging. This study explores the effect of electrical stimulation on fibroblasts in a culture medium containing different electrically-charged polysaccharide derivatives including alginate, hyaluronate, and chitosan derivatives. For this aim, an electrical stimulation, provided by a zigzag triboelectric nanogenerator (TENG), was exerted on fibroblasts in the presence of polysaccharides' solutions.

Sulfated polysaccharide as biomimetic biopolymers for tissue engineering scaffolds fabrication: Challenges and opportunities.

Sulfated polysaccharides play important roles in tissue engineering applications because of their high growth factor preservation ability and their native-like biological features. There are different sulfated polysaccharides based on different repeating units in the carbohydrate backbone, the position of the sulfate group, and the sulfation degree of the polysaccharide. These led to various sulfated polymers with different negative charge densities and resultant structure-property relationships.

Fabrication of affinity-based drug delivery systems based on electrospun chitosan sulfate/poly(vinyl alcohol) nanofibrous mats.

Benign electrospinning of chitosan in aqueous medium is an open challenge mainly due to its insolubility in neutral pH and inter- and intramolecular hydrogen bonding interactions. Here, we developed a simple and widely-used methodology to improve the chitosan electrospinnability through the sulfation of chitosan and its further mixing with poly(vinyl alcohol) for the first time. The FTIR, H NMR and elemental analyses showed the successful sulfation of chitosan.

Assessment of the Efficacy of an LL-37-Encapsulated Keratin Hydrogel for the Treatment of Full-Thickness Wounds.

Wound healing remains a burdensome healthcare problem due to moisture loss and bacterial infection. Advanced hydrogel dressings can help to resolve these issues by assisting and accelerating regenerative processes such as cell migration and angiogenesis because of the similarities between their composition and structure with natural skin. In this study, we aimed to develop a keratin-based hydrogel dressing and investigate the impact of the delivery of LL-37 antimicrobial peptide using this hydrogel in treating full-thickness rat wounds.

Fabrication of Cell-Laden AME-Loaded Collagen-Based Hydrogel Promotes Fibroblast Proliferation and Wound Healing .

Objective: The biological factors secreted from cells and cell-based products stimulate growth, proliferation, and migration of the cells in their microenvironment, and play vital roles in promoting wound healing. The amniotic membrane extract (AME), which is rich in growth factors (GFs), can be loaded into a cell-laden hydrogel and released to a wound site to promote the healing of the wound. The present study was conducted to optimize the concentration of the loaded AME that induces secretion of GFs and structural collagen protein from cell-laden AME-loaded collagen-based hydrogels, to promote wound healing .

Partial sulfation of gellan gum produces cytocompatible, body temperature-responsive hydrogels.

Gellan gum (GG) is a biodegradable polysaccharide and forms thermosensitive hydrogels by a helix-mediated mechanism. Unfortunately, the wide use of GG in tissue engineering has been restricted due to its dramatically higher gelation temperature than normal body temperature. Here, we show that partial sulfation of GG affords a cytocompatible body temperature-responsive hydrogel with an interesting thermoreversibility at 42 °C.

Hybrid gelatin-sulfated alginate scaffolds as dermal substitutes can dramatically accelerate healing of full-thickness diabetic wounds.

Diabetic foot ulcers (DFUs) are defined as chronic and non-healing wounds that cause skin disorders. Here, we introduce a novel biodegradable gelatin/sulfated alginate hybrid scaffold as a dermal substitute to accelerate the healing of full-thickness diabetic ulcers in a diabetic mouse model. The hybrid scaffold possessing different weight ratios of sulfated alginate, from 10 % up to 50 %, were prepared through chemical crosslinking by carbodiimide chemistry and further freeze-drying.

Antibacterial Host-Guest Intercalated LDH-Adorned Polyurethane for Accelerated Dermal Wound Healing.

Curcumin has a limited clinical application because of its extremely poor accessibility. In the present study, improved curcumin bioavailability within a castor oil polyurethane/layered double hydroxide (LDH) wound cover was achieved by preparing a curcumin -sulfonic acid calix[4]arene (SC4A) inclusion complex. Then, it was utilized to intercalate MgAl-layered double hydroxide (MgAl-LDH) nanosheets.

A supramolecular injectable hydrogel based on-cyclodextrin-grafted alginate and pluronic-amine loaded with kartogenin for chondrogenic differentiation of mesenchymal stem cells.

Owing to the similarity of hydrogels to cartilage extracellular matrix, they have been extensively utilized in the chondral lesions. Moreover, their tunable administration properties are desirable for reducing injuries in lesion sites. Generally, injectable hydrogels are mechanically weak, requiring some modifications for being used as a cell carrier in place of articular cartilage.

Regioselective sulfated chitosan produces a biocompatible and antibacterial wound dressing with low inflammatory response.

The aim of current study is to tailor chitosan derivate which is water-soluble while presents original biological features of chitosan. For this purpose, the 6-O chitosan sulfate (CS) with naked amine groups was synthesized via regioselective modification of chitosan (C) during which both crosslinking capacity and antibacterial properties of the C were remained intact. This was achieved by sulfation the C under controlled acidic conditions using chlorosulfonic acid/sulfuric acid mixture.

Micro- and nanotechnology in biomedical engineering for cartilage tissue regeneration in osteoarthritis.

Osteoarthritis, which typically arises from aging, traumatic injury, or obesity, is the most common form of arthritis, which usually leads to malfunction of the joints and requires medical interventions due to the poor self-healing capacity of articular cartilage. However, currently used medical treatment modalities have reported, at least in part, disappointing and frustrating results for patients with osteoarthritis. Recent progress in the design and fabrication of tissue-engineered microscale/nanoscale platforms, which arises from the convergence of stem cell research and nanotechnology methods, has shown promising results in the administration of new and efficient options for treating osteochondral lesions.

Anti-fatigue, highly resilient photocrosslinkable gellan gum hydrogels reinforced by flexible nanoparticulate polyurethane multi-crosslinkers.

In this study, multifunctional polyurethane nanoparticles (MPUNs) were embedded into the methacrylated gellan gum (MGG) to prepare stimuli-responsive hydrogels with improved mechanical properties including remarkable fatigue resistance and excellent self-recoverability. The photocurable MPUNs/MGG nanocomposite hydrogels with different formulations were synthesized through a facile and green solution mixing method. The result obtained from mechanical analysis displayed an excellent improvement in compression strength (120 6 ± 83.

Highly tough and ultrafast self-healable dual physically crosslinked sulfated alginate-based polyurethane elastomers for vascular tissue engineering.

Since vascular diseases are regarded as a major cause of death worldwide, developing engineered biomimetic elastomers with physicochemical and biological properties resembling those of the natural vascular tissues, is vital for vascular tissue engineering (VTE). This study reports synthesis of highly tough supramolecular biologically active alginate-based supramolecular polyurethane (BASPU) elastomers that benefit from the presence of two physical networks with different strength of soft tertiary ammonium-soft sulfate pairs, as strong ionic bonds, and soft tertiary ammonium-hard carboxylate groups, as the weak bonds. The presence of sulfate groups resulted in low Young's modulus, high toughness and stretchability, proper energy dissipation, ultrafast self-healing and complete healing efficiency of BASPU.

How does counter-cation substitution influence inter- and intramolecular hydrogen bonding and electrospinnability of alginates.

Despite numerous applications of nanofibrous alginate (Alg) mat, its facile fabrication via electrospinning is still challenging. The low alginate content compared to the carrier polymer and existence of impurities are the main drawbacks of existing approaches. The purpose of this research is both to study and improve alginate electrospinnability by focusing on the effect of inter- and intramolecular hydrogen bonding.

Co-delivery of minocycline and paclitaxel from injectable hydrogel for treatment of spinal cord injury.

Spinal cord injury (SCI) induces pathological and inflammatory responses that create an inhibitory environment at the site of trauma, resulting in axonal degeneration and functional disability. Combination therapies targeting multiple aspects of the injury, will likely be more effective than single therapies to facilitate tissue regeneration after SCI. In this study, we designed a dual-delivery system consisting of a neuroprotective drug, minocycline hydrochloride (MH), and a neuroregenerative drug, paclitaxel (PTX), to enhance tissue regeneration in a rat hemisection model of SCI.

Assessment of the Efficacy of Tributylammonium Alginate Surface-Modified Polyurethane as an Antibacterial Elastomeric Wound Dressing for both Noninfected and Infected Full-Thickness Wounds.

Risk factors of nonhealing wounds include persistent bacterial infections and rapid onset of dehydration; therefore, wound dressings should be used to accelerate the healing process by helping to disinfect the wound bed and provide moisture. Herein, we introduce a transparent tributylammonium alginate surface-modified cationic polyurethane (CPU) wound dressing, which is appropriate for full-thickness wounds. We studied the physicochemical properties of the dressing using Fourier transform infrared, H NMR, and C NMR spectroscopies and scanning electron microscopy, energy-dispersive X-ray, and thermomechanical analyses.

Improving anti-hemolytic, antibacterial and wound healing properties of alginate fibrous wound dressings by exchanging counter-cation for infected full-thickness skin wounds.

Nowadays, considerable effort is made to overcome bacterial diseases and combat bacterial resistance. In this context, development of safe and efficient antimicrobial wound dressings which can selectively fight against the bacteria and decrease disruption of normal cells such as red blood cells in wound bed is highly required. In this study, a series of ammonium salts of alginate were prepared and the role of different counter-cations including sodium, triethylammonium, tributylammonium and dihexylammonium were examined with respect to antimicrobial efficacy and selectivity as well as fibroblasts viability.

Fabrication challenges and trends in biomedical applications of alginate electrospun nanofibers.

Alginate as a naturally-derived biomaterial with marine algae sources has gained much attention in both laboratorial and industrial applications due to its structural and chemical resemblance to extracellular matrix (ECM) as well as desirable properties like biocompatibility, biodegradability, processability and low cost. Electrospun alginate nanofibrous scaffolds have found wide applications in biomedical field such as tissue engineering, biomedicine and drug delivery systems. However, electrospinning of alginate is challenging due to the low solubility and high viscosity of high molecular weight alginate, high density of intra- and intermolecular hydrogen bonding, polyelectrolyte nature of aqueous solution and lack of appropriate organic solvent.

Facile fabrication of sulfated alginate electrospun nanofibers.

Mass fabrication of sodium alginate nanofibers using single-nuzzle electrospinning process is an open challenge mainly due to its inter- and intramolecular hydrogen bonding, rigid chain conformation and low solubility. In this regards, we synthesized sodium sulfated alginate (SSA) through sulfation of hydroxyl functional groups of alginate. Not only decreases the hydrogen bonding density through the sulfation reaction, but the sulfated alginate also demonstrates more solubility in aqueous media compared to the pristine alginate.

Mechanical reinforcement of gellan gum polyelectrolyte hydrogels by cationic polyurethane soft nanoparticles.

Novel mechanically reinforced nanocomposite hydrogels (NCHs) were developed based on methacrylated gellan gum (MGG) and cationic polyurethane nanoparticles (CPUNs) through a green chemical approach. A series of NCHs were synthesized by the incorporation of CPUNs with weight ratios of 0, 10, 30 and 50 w/w% into the MGG solution, with two different methacrylation degrees (1.2, 5.