Ulvan/gelatin-based nanofibrous patches as a promising treatment for burn wounds

Characterization of ulvan polysaccharide extracted from Ulva pertusa and its effect on thermal, rheological, and gelling properties of rice flour

Three ulvan fractions (UPs 1-3) were extracted from Ulva pertusa via hot-water extraction. UP1 exhibited a molecular weight of 729,151 Da, while UPs 2 and 3 ranged from 19,952 to 750,384 Da. These fractions differed in monosaccharide, uronic acid, and sulfate levels. Zeta potentials for polysaccharide solutions (0.2-0.6 % w/v) ranged from -34.4 to -25.1, all demonstrating shear-thinning behavior. Incorporating UPs 1-3 solutions (0.2-0.6 % w/v) with rice flour increased gelatinization temperatures and modified pasting properties, increasing peak time, peak viscosity, and trough viscosity while reducing breakdown, final, and setback viscosities. Ulvan polysaccharide improved the viscous behavior of rice flour paste, indicated by increased loss modulus and tan δ (p > 0.05). Furthermore, ulvan polysaccharide improved the microstructure and texture of rice flour gel, with UP1 (0.6 % w/v) forming denser matrices and better texture. Molecular docking analysis suggested that hydrogen bonding is the primary interaction between rice glutelin and ulvan components.

Healing Potential of the Marine Polysaccharides Carrageenan and Ulvan on Second-Degree Burns

The treatment of second-degree burn wounds presents a significant clinical challenge, often characterized by prolonged healing times and risk of complications. In this study, the wound healing potential of bioactive marine sulfated polysaccharides ulvan and carrageenan formulated in gels at concentrations of 1.5%, 5.0%, and 10% w/w was evaluated. Hairless female SKH-hr2 mice (n = 7 per treatment) with burn-inflamed skin were treated with the polysaccharide-based gels, and the therapeutic efficacy was assessed using a comprehensive array of evaluation methods, including a histopathological analysis, clinical observation, photo-documentation, an image analysis, an evaluation of biophysical skin parameters, and FT-IR spectroscopy. Our findings indicate that the 10% w/w carrageenan gel exhibited significant enhancement in wound healing, particularly in the early stages of the healing process. This was evidenced by the restoration of the α-helix structure of collagen and the configuration of glycosaminoglycans, as demonstrated by FT-IR absorption bands of the skin both in vivo and ex vivo. Furthermore, the 5% w/w ulvan gel also demonstrated notable efficacy in promoting wound healing, particularly in the later stages of the healing process. These results suggest that carrageenan and ulvan gels hold promise for improving the efficiency of wound healing in second-degree burn wounds. Our study contributes to the understanding of the therapeutic potential of marine polysaccharides and provides insights into their mechanism of action in promoting wound healing.

Graphene-silymarin-loaded chitosan/gelatin/hyaluronic acid hybrid constructs for advanced full-thickness burn wound management

Burn wounds (BWs) with extensive blood loss, along with bacterial infections and poor healing, may become detrimental and pose significant rehabilitation obstacles in medical facilities. Therefore, the freeze-drying method synthesized novel hemocompatible chitosan, gelatin, and hyaluronic acid infused with graphene oxide-silymarin (CGH-SGO) hybrid constructs for application as a BW patch. Most significantly, synthesized hybrid constructs exhibited an interconnected-porous framework with precise pore sizes (≈118.52 µm) conducive to biological functions. Furthermore, the FTIR and XRD analyses document the constructs' physiochemical interactions. Similarly, enhanced swelling ratios, adequate WVTR (736 ± 78 g m-2 hr-1), and bio-degradation rates were seen during the physiological examination of constructs. Following the in vitro investigations, SMN-GO added to constructs improved their anti-bacterial (against E.coli and S. aureus), anti-oxidant, hemocompatible, and bio-compatible characteristics in conjunction with prolonged drug release. Furthermore, in vivo, implanting constructs on wounds exhibited significant acceleration in full-thickness burn wound (FT-BW) healing on the 14th day (CGH-SGO: 95 ± 2.1 %) in contrast with the control (Gauze: 71 ± 4.2 %). Additionally, contrary to gauze, the in vivo rat tail excision model administered with constructs assured immediate blood clotting. Therefore, CGH-SGO constructs with an improved porous framework, anti-bacterial activity, hemocompatibility, and biocompatibility could represent an attractive option for healing FT-BWs.

Electrospun Nanofiber Scaffold for Skin Tissue Engineering: A Review

Skin tissue engineering (STE) is widely regarded as an effective approach for skin regeneration. Several synthetic biomaterials utilized for STE have demonstrated favorable fibrillar characteristics, facilitating the regeneration of skin tissue at the site of injury, yet they have exhibited a lack of in situ degradation. Various types of skin regenerative materials, such as hydrogels, nanofiber scaffolds, and 3D-printing composite scaffolds, have recently emerged for use in STE. Electrospun nanofiber scaffolds possess distinct advantages, such as their wide availability, similarity to natural structures, and notable tissue regenerative capabilities, which have garnered the attention of researchers. Hence, electrospun nanofiber scaffolds may serve as innovative biological materials possessing the necessary characteristics and potential for use in tissue engineering. Recent research has demonstrated the potential of electrospun nanofiber scaffolds to facilitate regeneration of skin tissues. Nevertheless, there is a need to enhance the rapid degradation and limited mechanical properties of electrospun nanofiber scaffolds in order to strengthen their effectiveness in soft tissue engineering applications in clinical settings. This Review centers on advanced research into electrospun nanofiber scaffolds, encompassing preparation methods, materials, fundamental research, and preclinical applications in the field of science, technology, and engineering. The existing challenges and prospects of electrospun nanofiber scaffolds in STE are also addressed.

Anti-inflammatory potential of ulvan

Green seaweeds are a widespread group of marine macroalgae that could be regarded as biorenewable source of valuable compounds, in particular sulfated polysaccharides like ulvans with interesting biological properties. Among them, anti-inflammatory activity represents an interesting target, since ulvans could potentially avoid side effects of conventional therapies. However, a great variability in ulvan content, composition, structure and properties occurs depending on seaweed specie and growth and processing conditions. All these aspects should be carefully considered in order to have reproducible and well characterized products. This review presents some concise ideas on ulvan composition and general concepts on inflammation mechanisms. Then, the main focus is on the importance of adequate selection of extraction, depolymerization and purification technologies followed by an updated survey on anti-inflammatory properties of ulvans through modulation of different signaling pathways. The potential application in a number of diseases, with special emphasis on inflammaging, gut microbiota dysbiosis, wound repair, and metabolic diseases is also discussed. This multidisciplinary overview tries to present the potential of ulvans considering not only mechanistic, but also processing and applications aspects, trusting that it can aid in the development and application of this widely available and renewable resource as an efficient and versatile anti-inflammatory agent.

Biochemical characterization of a new ulvan lyase and its applicability in utilization of ulvan and preparation of ulva oligosaccharides

Ulva is globally distributed specie and has a high economic value. Ulvan is one of the main active substances in Ulva, which has a variety of biological properties. Ulvan lyase degrades ulvan through a β-elimination mechanism which cleaves the β-glycosidic bond between Rha3S and GlcA or IdoA. The complex monosaccharide composition of ulvan makes it promising for use in food and pharmaceutical applications. This thesis explores a putative ulvan lyase from Alteromonas sp. KUL_42. We expressed and purified the protein, performed a series of characterizations and signal peptide had been removed. The results showed that the protein molecular weight of ULA-2 was 53.97 kDa, and it had the highest catalytic activity at 45 °C and pH 8.0 in Tris-HCl buffer. The Km and Vmax values were 2.24 mg · mL-1 and 2.048 μmol · min-1 · mL-1, respectively. The activity of ULA-2 was able to maintain more than 80% at 20 ~ 30 °C. ESI-MS analysis showed that the primary end-products were mainly disaccharides to tetrasaccharides. The study of ULA-2 enriches the ulvan lyase library, promotes the development and high-value utilization of Ulva resources, and facilitates further research applications of ulvan lyase in ulva oligosaccharides.

Electrospun Nanofibers for Biomedical, Sensing, and Energy Harvesting Functions

The process of electrospinning is over a century old, yet novel material and method achievements, and later the addition of nanomaterials in polymeric solutions, have spurred a significant increase in research innovations with several unique applications. Significant improvements have been achieved in the development of electrospun nanofibrous matrices, which include tailoring compositions of polymers with active agents, surface functionalization with nanoparticles, and encapsulation of functional materials within the nanofibers. Recently, sequentially combining fabrication of nanofibers with 3D printing was reported by our group and the synergistic process offers fiber membrane functionalities having the mechanical strength offered by 3D printed scaffolds. Recent developments in electrospun nanofibers are enumerated here with special emphasis on biomedical technologies, chemical and biological sensing, and energy harvesting aspects in the context of e-textile and tactile sensing. Energy harvesting offers significant advantages in many applications, such as biomedical technologies and critical infrastructure protection by using the concept of finite state machines and edge computing. Many other uses of devices using electrospun nanofibers, either as standalone or conjoined with 3D printed materials, are envisaged. The focus of this review is to highlight selected novel applications in biomedical technologies, chem.-bio sensing, and broadly in energy harvesting for use in internet of things (IoT) devices. The article concludes with a brief projection of the future direction of electrospun nanofibers, limitations, and how synergetic combination of the two processes will open pathways for future discoveries.

A propitious role of marine sourced polysaccharides: Drug delivery and biomedical applications

Numerous compounds, with extensive applications in biomedical and biotechnological fields, are present in the oceans, which serve as a prime renewable source of natural substances, further promoting the development of novel medical systems and devices. Polysaccharides are present in the marine ecosystem in abundance, promoting minimal extraction costs, in addition to their solubility in extraction media, and an aqueous solvent, along with their interactions with biological compounds. Certain algae-derived polysaccharides include fucoidan, alginate, and carrageenan, while animal-derived polysaccharides comprise hyaluronan, chitosan and many others. Furthermore, these compounds can be modified to facilitate their processing into multiple shapes and sizes, as well as exhibit response dependence to external conditions like temperature and pH. All these properties have promoted the use of these biomaterials as raw materials for the development of drug delivery carrier systems (hydrogels, particles, capsules). The present review enlightens marine polysaccharides providing its sources, structures, biological properties, and its biomedical applications. In addition to this, their role as nanomaterials is also portrayed by the authors, along with the methods employed to develop them and associated biological and physicochemical properties designed to develop suitable drug delivery systems.

Development of Novel Pharmaceutical Forms of the Marine Bioactive Pigment Echinochrome A Enabling Alternative Routes of Administration

Echinochrome A (EchA), a marine bioactive pigment isolated from various sea urchin species, is the active agent of the clinically approved drug Histochrome^®. EchA is currently only available in the form of an isotonic solution of its di- and tri-sodium salts due to its poor water solubility and sensitivity to oxidation. Electrospun polymeric nanofibers have lately emerged as promising drug carriers capable of improving the dissolution and bioavailability of drugs with limited water solubility. In the current study, EchA isolated from sea urchins of the genus Diadema collected at the island of Kastellorizo was incorporated in electrospun micro-/nanofibrous matrices composed of polycaprolactone and polyvinylpyrrolidone in various combinations. The physicochemical properties of the micro-/nanofibers were characterized using SEM, FT-IR, TGA and DSC analyses. The fabricated matrices exhibited variable dissolution/release profiles of EchA, as evidenced in in vitro experiments using gastrointestinal-like fluids (pH 1.2, 4.5 and 6.8). Ex vivo permeability studies using the EchA-loaded micro-/nanofibrous matrices showed an increased permeation of EchA across the duodenum barrier. The results of our study clearly show that electrospun polymeric micro-/nanofibers represent promising carriers for the development of new pharmaceutical formulations with controlled release, as well as increased stability and solubility of EchA, suitable for oral administration, while offering the potential for targeted delivery.

Valorization of Fish Waste: Isolation and Characterization of Acid- and Pepsin-Soluble Collagen from the Scales of Mediterranean Fish and Fabrication of Collagen-Based Nanofibrous Scaffolds

In search of alternative and sustainable sources of collagenous materials for biomedical applications, the scales of five Mediterranean fish species-fished in high tonnage in the Mediterranean region since they represent popular choices for the local diet-as well as those of the Atlantic salmon for comparison purposes, were comparatively studied for their acid- and pepsin-soluble collagen content. Fish scales that currently represent a discarded biomass of no value could be efficiently exploited for the production of a high added-value biomaterial. The isolated collagenous materials, which showed the typical electrophoretic patterns of type I collagen, were morphologically and physicochemically characterized. Using scanning electron microscopy the fibrous morphology of the isolated collagens was confirmed, while the hydroxyproline content, in conjunction with infrared spectroscopy and X-ray diffraction studies verified the characteristic for collagen amino acid profile and its secondary structure. The acid- and pepsin-soluble collagens isolated from the fish scales were blended with the bioactive sulfated marine polysaccharide ulvan and polyethylene oxide and electrospun to afford nanofibrous scaffolds that could find applications in the biomedical sector.

Development of Ulvan-Containing Liposomes as Antibacterial Drug Delivery Platforms

Liposomes, due to their safety profile and targeting ability, are among the most studied nanocarriers as antimicrobial delivery systems. However, due to lack of stability and the non-specific interaction of liposomes with cells and proteins, their use is relatively limited. Aiming to overcome these drawbacks, it was envisaged that incorporation of ulvan, a bioactive marine sulfated polysaccharide isolated from green algae, in liposomes could improve their physicochemical properties and overall stability. Thus, we initially studied the interactions of ulvan with neutral, negatively, and positively charged lipids using Differential Scanning Calorimetry and subsequently, based on the obtained results, we prepared the respective ulvan–containing neutral and charged liposomes, where ulvan interacts with both lipid chains and polar groups in the liposomal bilayer. In a further step, we entrapped in the liposomes fusidic acid, used as a model antibacterial drug, and proceeded with the evaluation of their antibacterial activity against Staphylococcus aureus. The physicochemical properties (size and ζ-potential), stability, morphology, and entrapment efficiency of the prepared liposomal formulations were determined.

Ulvan-Based Nanofibrous Patches Enhance Wound Healing of Skin Trauma Resulting from Cryosurgical Treatment of Keloids

Keloids are skin fibroproliferative disorders, resulting from abnormal healing of deep cutaneous injuries. Cryosurgery, the most common treatment for keloids, causes skin traumas. Even though the clinical practice of cryosurgery has increased, effective wound healing therapy is still lacking. In this investigation, nonwoven nanofibrous patches composed of ulvan, a marine sulfated polysaccharide exhibiting anti-inflammatory and antioxidant activities, and polyethylene oxide (PEO) were fabricated through electrospinning and characterized. Their wound healing efficacy on skin traumas resulting from cryosurgical treatment of keloids was clinically tested and evaluated in comparison to a reference product. Twenty-four volunteer patients undergoing cryosurgery as a treatment of keloids were selected to apply either the ulvan/PEO patch or the reference product for 21 days. The ulvan/PEO patch, 21 days after cryosurgery, showed significant wound healing, elimination of skin inflammation, restoration of biophysical parameters similar to normal values and significant decrease in haemoglobin concentration, skin texture and volume, while no discomfort or adverse reaction was observed. In contrast, the reference product showed inferior performance in all evaluated parameters. The designed ulvan/PEO patch represents the first wound dressing to effectively heal skin trauma after cryosurgical treatment of keloids.