Development of the inorganic nanoparticles reinforced alginate‐based hybrid fiber for wound care and healing

One-Step Microfluidic Fabrication of Bioinspired Microfibers with a Spindle-Knot Structure for Fog Harvest

Many biomimetic microfibers have been designed from spider silk to collect water efficiently from humid air as a result of its periodic spindle-knot structure, which enhances the direct movement and convergence of captured fog droplets. Here, a hydrodynamic flow-focusing microfluidic device with a theta-shaped tube is designed for the one-step fabrication of bioinspired microfibers with a spindle-knot structure for fog harvest. The morphology of the structured microfibers, including height, width, and spacing of spindle knots, can be adjusted readily by regulating the flow rate of specific phases. The production rate of these structured microfibers can reach 1100 cm/min. Moreover, the capture, transportation, and collection performance of fog droplets on various microfibers are investigated in a fog collection platform. It is demonstrated that our one-step microfluidic device presents a ready method for the fabrication of structured microfibers with spindle knots, which provide a significant facilitation on efficient fog capture and water collection.

Alginate templated synthesis, characterization and in vitro osteogenic evaluation of strontium-substituted hydroxyapatite

The objective of this study is to explore the potential role of alginate (Alg) in the crystallization of metal-substituted hydroxyapatite, with application in orthopaedic reconstruction. The alginate at different concentrations (0.5 and 1.0 wt%) facilitated in situ mineralization of hydroxyapatite (HA) and strontium-substituted HA (SHA, 10 and 30 mol%). The incorporation of the biopolymer and dopant induced notable changes in HA, including reduced crystal size from 31.0 to 16.4 nm and increased lattice volume from 577.3 to 598.0 Å3. The superior affinity of alginate for Sr2+ than for Ca2+ resulted in higher residual alginate in Alg/SHA (13.0 to 19.0 %) compared to Alg/HA (7.1 to 8.2 %). This residual alginate influenced composite properties: surface charge decreased from -26.5 to -45.7 mV, microhardness increased from 0.33 to 0.54 GPa, and dissolution increased from 0.17 to 0.39 %. The in vitro studies revealed that strontium substitution as well as the organization and crystallographic aspects of apatite regulated osteoblastic cell survival, proliferation, differentiation, and biomineralization. The findings suggest that an alginate concentration of 0.5 wt% is optimal for the crystallization of SHA with 10 mol% substitution, and its resulting composite possesses the ideal biomechanical properties to imitate native bone.

Antioxidant, Anti-Inflammatory Effects and Ability to Stimulate Wound Healing of a Common-Plantain Extract in Alginate Gel Formulations

Our study aimed to investigate the biological effects of a common-plantain (Plantago major L.) extract, encapsulated in alginate, on dermal human fibroblast cultures in vitro, in view of its potential use as a wound healing adjuvant therapy. Common-plantain extracts were obtained by infusion and ultrasound extraction, and their total polyphenolic content and antioxidant capacity were determined by spectrophotometry. The best extract, which was obtained by infusion, was further encapsulated in sodium alginate in two different formulations. Fourier Transform Infrared Spectroscopy (FTIR) was used to demonstrate the existing interactions in the obtained common-plantain extract in the alginate formulations. The encapsulation efficiency was evaluated based on the total polyphenol content. These alginate gel formulations were further used in vitro to determine their biocompatibility and antioxidant and anti-inflammatory effects by spectrophotometry and ELISA, as well as their ability to stimulate fibroblast migration (scratch test assay) at different time points. In addition, the collagen 1 and 3 levels were determined by Western blot analysis. The data showed that the microencapsulated plantain extract formulations induced an antioxidant, anti-inflammatory effect, enhanced collagen production and increased wound closure in the first 8 h of their application. These results are encouraging for the use of this alginate plantain extract formulation as an adjuvant for skin wound healing.

Polysaccharide based transdermal patches for chronic wound healing: Recent advances and clinical perspective

Polysaccharides form a major class of natural polymers with diverse applications in biomedical science and tissue engineering. One of the key thrust areas for polysaccharide materials is skin tissue engineering and regeneration, whose market is estimated to reach around 31 billion USD globally by 2030, with a compounded annual growth rate of 10.46 %. Out of this, chronic wound healing and management is a major concern, especially for underdeveloped and developing nations, mainly due to poor access to medical interventions for such societies. Polysaccharide materials have shown promising results and clinical potential in recent decades with regard to chronic wound healing. Their low cost, ease of fabrication, biodegradability, and ability to form hydrogels make them ideal candidates for managing and healing such difficult-to-heal wounds. The present review presents a summary of the recently explored polysaccharide-based transdermal patches for managing and healing chronic wounds. Their efficacy and potency of healing both as active and passive wound dressings are evaluated in several in-vitro and in-vivo models. Finally, their clinical performances and future challenges are summarized to draw a road map towards their role in advanced wound care.

Alginate-Based Bio-Composites and Their Potential Applications

Over the last two decades, bio-polymer fibers have attracted attention for their uses in gene therapy, tissue engineering, wound-healing, and controlled drug delivery. The most commonly used bio-polymers are bio-sourced synthetic polymers such as poly (glycolic acid), poly (lactic acid), poly (e-caprolactone), copolymers of polyglycolide and poly (3-hydroxybutyrate), and natural polymers such as chitosan, soy protein, and alginate. Among all of the bio-polymer fibers, alginate is endowed with its ease of sol–gel transformation, remarkable ion exchange properties, and acid stability. Blending alginate fibers with a wide range of other materials has certainly opened many new opportunities for applications. This paper presents an overview on the modification of alginate fibers with nano-particles, adhesive peptides, and natural or synthetic polymers, in order to enhance their properties. The application of alginate fibers in several areas such as cosmetics, sensors, drug delivery, tissue engineering, and water treatment are investigated. The first section is a brief theoretical background regarding the definition, the source, and the structure of alginate. The second part deals with the physico-chemical, structural, and biological properties of alginate bio-polymers. The third part presents the spinning techniques and the effects of the process and solution parameters on the thermo-mechanical and physico-chemical properties of alginate fibers. Then, the fourth part presents the additives used as fillers in order to improve the properties of alginate fibers. Finally, the last section covers the practical applications of alginate composite fibers.

Fabrication, Property and Application of Calcium Alginate Fiber: A Review

As a natural linear polysaccharide, alginate can be gelled into calcium alginate fiber and exploited for functional material applications. Owing to its high hygroscopicity, biocompatibility, nontoxicity and non-flammability, calcium alginate fiber has found a variety of potential applications. This article gives a comprehensive overview of research on calcium alginate fiber, starting from the fabrication technique of wet spinning and microfluidic spinning, followed by a detailed description of the moisture absorption ability, biocompatibility and intrinsic fire-resistant performance of calcium alginate fiber, and briefly introduces its corresponding applications in biomaterials, fire-retardant and other advanced materials that have been extensively studied over the past decade. This review assists in better design and preparation of the alginate bio-based fiber and puts forward new perspectives for further study on alginate fiber, which can benefit the future development of the booming eco-friendly marine biomass polysaccharide fiber.

Synthesis and In Vitro/Ex Vivo Characterizations of Ceftriazone-Loaded Sodium Alginate/Poly(Vinyl Alcohol) Clay Reinforced Nanocomposites: Possible Applications in Wound Healing

(1) Background: Nanocomposite films are widely applied in the pharmaceutical industry (e.g., nanodrug delivery systems—NDDS). Indeed, these nanomaterials can be produced at a large industrial scale and display valuable properties (e.g., antibacterial, renewability, biodegradability, bioavailability, safety, tissue-specific targeting, and biocompatibility), which can enhance the activity of conventional marketed drugs. (2) Aim: To fabricate and investigate the in vitro properties of the antibiotic ceftriaxone sodium (CTX) once encapsulated into sodium alginate (SA)/poly(vinyl alcohol)PVA-clay reinforced nanocomposite films. (3) Methods: Different ratios of the polymers (i.e., SA, PVA) and CTX drug were used for the synthesis of nanocomposite films by solvent casting technique. Montmorillonite (MMT), modified organically, was added as a nanofiller to increase their thermal and mechanical strength. The prepared samples were physically characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and energy-dispersive X-ray analysis (EDX). The physicochemical behavior (i.e., swelling, erosion, dissolution/drug release behavior and rat skin permeation) was also assessed. Comparisons were made with the currently marketed free CTX dosage form. (4) Results: TGA of the nanoformulation showed increased thermostability. XRD revealed its semi-crystalline nature. SEM depicted a homogeneous drug-loaded SA/PVA nanocomposite with an average size ranging between 300 and 500 nm. EDX confirmed the elemental composition and uniform distribution of mixing components. The water entrapment efficiency study showed that the highest swelling and erosion ratio is encountered with the nanoformulations S100(3) and S100D15(3). Ex vivo permeation revealed a bi-step discharge mode with an early burst liberation chased by continued drug discharge of devised nanoparticles (NPs). The dissolution studies of the drug-loaded polymer nanocomposites elicited sustained pH-dependent drug release. The cumulative drug release was the highest (90.93%) with S100D15(3). (5) Conclusion: S100D15(3) was the finest formulation. To the best of our knowledge, we also pioneered the use of solvent casting for the preparation of such nanoformulations. Polymers and reinforcing agent, concentrations and pH were rate-deterring features for the preparation of the optimized formulation. Thus, CTX-loaded SA/PVA-MMT reinforced nanocomposite appeared as a promising nanodrug delivery system (NDDS) based on its in vitro physicochemical properties.

Poly(lactic acid)/Zinc/Alginate Complex Material: Preparation and Antimicrobial Properties

The aim of this study was to investigate an antimicrobial and degradable composite material consisting of melt-blown poly(lactic acid) nonwoven fabrics, alginate, and zinc. This paper describes the method of preparation and the characterization of the physicochemical and antimicrobial properties of the new fibrous composite material. The procedure consists of fabrication of nonwoven fabric and two steps of dip-coating modification: (1) impregnation of nonwoven samples in the solution of alginic sodium salt and (2) immersion in a solution of zinc (II) chloride. The characterization and analysis of new material included scanning electron microscopy (SEM), specific surface area (SSA), and total/average pore volume (BET). The polylactide/alginate/Zn fibrous composite were subjected to microbial activity tests against colonies of Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli) bacterial strains, and the following fungal strains: Aspergillus niger van Tieghem and Chaetomium globosum. These results lay a technical foundation for the development and potential application of new composite as an antibacterial/antifungal material in biomedical areas.