PDGF-AA loaded photo-crosslinked chitosan-based hydrogel for promoting wound healing

State-of-the-art in natural hydrogel-based wound dressings: Design, functionalization, and fabrication approaches

Natural hydrogel-based wound dressings, synthesized from biopolymers such as chitosan, sodium alginate, and cellulose, are gaining recognition in wound care due to their ability to promote healing through biocompatibility, moisture retention, and biodegradability. These materials foster an ideal healing environment by supporting cell proliferation and tissue regeneration while providing a protective barrier against infection. For chronic or infected wounds, enhancing the therapeutic performance of these hydrogels is essential. This review critically evaluates advanced functionalization strategies, including chemical modifications to optimize hydrogel properties, the incorporation of bioactive agents like growth factors and antimicrobial compounds, and the development of stimuli-responsive hydrogels that adjust to environmental cues such as pH, temperature, and enzymatic activity. Furthermore, fabrication techniques-such as solution casting, freeze-drying, electrospinning, and 3D printing-are discussed for their potential to generate tailored dressings with specific mechanical properties and bioactive capabilities. By highlighting key innovations and challenges, this review provides a comprehensive roadmap for the design, functionalization, and fabrication of natural hydrogel-based wound dressings, identifying critical areas for future research and development.

Porous Sodium Carboxymethyl Starch Microspheres for Hemostasis and Skin Wound Healing

An effective and rapid hemostatic material with flexible properties for clinical wound dressings is still an unmet need. Herein, a porous sodium carboxymethyl starch (CMS-Na-P) hemostatic microsphere was successfully fabricated through polysaccharide fluffy aggregate (PSFA) technology with a facile and low-cost process. CMS-Na-P exhibited rapid water absorption capabilities alongside favorable cytocompatibility and hemocompatibility. Additionally, CMS-Na-P could absorb red blood cells (RBCs), adhere to and activate platelets, and shorten clotting time in vitro. More importantly, its good in vivo hemostatic ability was further demonstrated against hemorrhage in rat liver and tail, pig superficial skin, superficial body vein, superficial abdominal vein, and femoral artery. Meanwhile, in a rat full-thickness skin defect model, CMS-Na-P could enhance wound healing through accelerated epidermal regeneration and collagen deposition. These properties make CMS-Na-P a promising candidate for treating bleeding and full-thickness wounds.

The role of platelet-rich plasma in biomedicine: A comprehensive overview

Biomedicine has seen significant advancements in the 21st century, with platelet-rich plasma (PRP) playing a crucial role in clinical practice. This blood derivative, enriched with platelet components, has shown great potential for promoting tissue repair and regeneration. Its wide range of applications and the presence of anti-inflammatory and growth-promoting factors make it a valuable tool in the field of biomedicine. The exploration of PRP in clinical settings has been gaining momentum. Despite its cost-effectiveness, safety, and therapeutic efficacy, the widespread clinical adoption of PRP has been hindered by the absence of consistent preparation standards and standardized treatment protocols. This article provides a comprehensive analysis of the clinical uses, physiological roles, molecular mechanisms, and preparation techniques of PRP in biomedicine. The aim is to offer a thorough understanding of the potential applications and benefits of PRP in medical practice.

In Situ-Forming, Adhesive, and Antioxidant Chitosan Hydrogels for Accelerated Wound Healing

Antioxidant hydrogels that can provide a moist environment and scavenge reactive oxygen species have emerged as highly potential wound dressing materials. In situ-forming and good tissue adhesiveness will make them more desirable, as they can fill the irregular wound defect, stick to the wound, and offer intimate contact with the wound. Herein, a hydrogel dressing combining in situ-forming, good tissue adhesiveness, and excellent antioxidant capabilities was developed by simply conjugating dopamine onto carboxymethyl chitosan. The introduction of dopamine allows in situ gelation of the polymer under mild conditions using an HRP-catalyzed cross-linking reaction. The introduction of dopamine also endows the hydrogels with suitable tissue-adhesion properties. Excellent antioxidant properties were also imparted as a result of the introduction of dopamine. Thanks to the favorable moist environment provided by the hydrogel and the effectively mitigated oxidative stress at wound sites, accelerated healing and reduced scar formation were observed in a rat full-thickness skin wound model.

Advances of naturally derived biomedical polymers in tissue engineering

The extensive utilization of natural polymers in tissue engineering is attributed to their excellent biocompatibility, degradability, and resemblance to the natural extracellular matrix. These polymers have a wide range of applications such as delivering therapeutic medicine, detecting diseases, sensing biological substances, promoting tissue regeneration, and treating diseases. This is a brief review of current developments in the properties and uses of widely used biomedical polymers derived from nature. Additionally, it explores the correlation between the characteristics and functions of these materials in different biomedical applications and highlights the prospective direction for the advancement of natural polymer materials in tissue engineering.

Cord Blood Platelet Lysate-Loaded Thermo-Sensitive Hydrogels for Potential Treatment of Chronic Skin Wounds

BACKGROUND/OBJECTIVES

Chronic skin wounds (CSWs) are a worldwide healthcare problem with relevant impacts on both patients and healthcare systems. In this context, innovative treatments are needed to improve tissue repair and patient recovery and quality of life. Cord blood platelet lysate (CB-PL) holds great promise in CSW treatment thanks to its high growth factors and signal molecule content. In this work, thermo-sensitive hydrogels based on an amphiphilic poly(ether urethane) (PEU) were developed as CB-PL carriers for CSW treatment.

METHODS

A Poloxamer 407®-based PEU was solubilized in aqueous medium (10 and 15% w/v) and added with CB-PL at a final concentration of 20% v/v. Hydrogels were characterized for their gelation potential, rheological properties, and swelling/dissolution behavior in a watery environment. CB-PL release was also tested, and the bioactivity of released CB-PL was evaluated through cell viability, proliferation, and migration assays.

RESULTS

PEU aqueous solutions with concentrations in the range 10-15% w/v exhibited quick (within a few minutes) sol-to-gel transition at around 30-37 °C and rheological properties modulated by the PEU concentration. Moreover, CB-PL loading within the gels did not affect the overall gel properties. Stability in aqueous media was dependent on the PEU concentration, and payload release was completed between 7 and 14 days depending on the polymer content. The CB-PL-loaded hydrogels also showed biocompatibility and released CB-PL induced keratinocyte migration and proliferation, with scratch wound recovery similar to the positive control (i.e., CB-PL alone).

CONCLUSIONS

The developed hydrogels represent promising tools for CSW treatment, with tunable gelation properties and residence time and the ability to encapsulate and deliver active biomolecules with sustained and controlled kinetics.

A photocrosslinkable and anti-inflammatory hydrogel of loxoprofen-conjugated chitosan methacrylate

Polymer-drug conjugates are widely used for drug delivery. Herein, we report an injectable hydrogel for local delivery of nonsteroidal anti-inflammatory drugs (NSAIDs) using chitosan (CS) as a carrier polymer. Loxoprofen (LOX) was conjugated to the backbone of CS via carbodiimide chemistry to obtain the LOX-CS conjugate. This conjugation transformed the water-insoluble unmodified CS into the water-soluble LOX-CS conjugate. In particular, the LOX-CS conjugate did not precipitate at pH 7, allowing smooth subsequent chemical modification with methacrylic anhydride (MA) to synthesize LOX-CS methacrylate (LOX-CS-MA) with significantly higher methacrylation substitution. The LOX-CS-MA was capable of in situ gel formation under visible light irradiation in the presence of a benzoin-2,4,6-trimethylbenzoylphosphinate lithium (LAP) photoinitiator. Our results show that the LOX-CS-MA hydrogel exhibited good cytocompatibility and blood compatibility. It promoted M2 polarization, inhibited pro-inflammatory gene expression, and upregulated anti-inflammatory gene expression of macrophages. Furthermore, the LOX-CS-MA hydrogel significantly reduced reactive oxygen species (ROS) and nitric oxide (NO) produced by lipopolysaccharide (LPS)-stimulated macrophages. A subcutaneous implanted LOX-CS-MA hydrogel in a rat model revealed significantly reduced inflammatory cell density, decreased cell infiltration, and a much thinner fibrous capsule compared to the CS methacrylate (CS-MA) hydrogel, thus markedly alleviating the inflammatory response. This study highlights the feasibility of CS-drug conjugates in preparing CS-based methacrylate hydrogels for sustained drug release.

A 3D self-floating solar vapor generator based on a novel self-healing aero-hydrogel containing peach gum polysaccharide with durability and continuous operation

Solar energy interfacial evaporation represents a promising and sustainable approach with considerable potential for seawater desalination and wastewater treatment. Nonetheless, creating durable evaporators for continuous operation presents a challenge. Motivated by natural self-healing mechanisms, this study developed a novel 3D hybrid aero-hydrogel, which exhibited a self-healing efficiency of 89.4 % and an elongation at break post-healing of 637.7 %, featuring self-healing capabilities and continuous operation potential. Especially, the incorporation of hyperbranched water-soluble polymers (peach gum polysaccharide) endow the final solar water evaporators with a lower evaporation enthalpy of water, resulting in that the refined SVG3, with a notable water surface architecture and an expanded evaporation area, achieved a steam generation rate of 2.13 kg m-2 h-1 under 1 Sun. Notably, SVG2 achieved a high evaporation rate of 2.43 kg m-2 h-1 with the combined energy input of 1 Sun and 6 V, significantly surpassing the rate of 1.96 kg m-2 h-1 without voltage input. The results indicate that electrical energy significantly enhances and synergizes with SVG, facilitating continuous operation both day and night through the combined use of solar energy and electrical input. This study offers insightful perspectives for the strategic design of multifunctional hydrogels for solar water evaporation.

Trends in sustainable chitosan-based hydrogel technology for circular biomedical engineering: A review

Eco-friendly materials have emerged in biomedical engineering, driving major advances in chitosan-based hydrogels. These hydrogels offer a promising green alternative to conventional polymers due to their non-toxicity, biodegradability, biocompatibility, environmental friendliness, affordability, and easy accessibility. Known for their remarkable properties such as drug encapsulation, delivery capabilities, biosensing, functional scaffolding, and antimicrobial behavior, chitosan hydrogels are at the forefront of biomedical research. This paper explores the fabrication and modification methods of chitosan hydrogels for diverse applications, highlighting their role in advancing climate-neutral healthcare technologies. It reviews significant scientific advancements and trends chitosan hydrogels focusing on cancer diagnosis, drug delivery, and wound care. Additionally, it addresses current challenges and green synthesis practices that support a circular economy, enhancing biomedical sustainability. By providing an in-depth analysis of the latest evidence on climate-neutral management, this review aims to facilitate informed decision-making and foster the development of sustainable strategies leveraging chitosan hydrogel technology. The insights from this comprehensive examination are pivotal for steering future research and applications in sustainable biomedical solutions.

Protamine-grafted carboxymethyl chitosan based hydrogel with adhesive and long-term antibacterial properties for hemostasis and skin wound healing

In this study, we developed a tissue-adhesive and long-term antibacterial hydrogel consisting of protamine (PRTM) grafted carboxymethyl chitosan (CMC) (PCMC), catechol groups modified CMC (DCMC), and oxidized hyaluronic acid (OHA), named DCMC-OHA-PCMC. According to the antibacterial experiments, the PCMC-treated groups showed obvious and long-lasting inhibition zones against E. coli (and S. aureus), and the corresponding diameters varied from 10.1 mm (and 15.3 mm) on day 1 to 9.8 mm (and 15.3 mm) on day 7. The DCMC-OHA-PCMC hydrogel treated groups also exhibited durable antibacterial ability against E. coli (and S. aureus), and the antibacterial rates changed from 99.3 ± 0.21 % (and 99.6 ± 0.36 %) on day 1 to 76.2 ± 1.74 % (and 84.2 ± 1.11 %) on day 5. Apart from good mechanical and tissue adhesion properties, the hydrogel had excellent hemostatic ability mainly because of the grafted positive-charged PRTM. As the animal assay results showed, the hydrogel was conducive to promoting the deposition of new collagen (0.84 ± 0.03), the regeneration of epidermis (98.91 ± 6.99 μm) and wound closure in the process of wound repairing. In conclusion, the presented outcomes underline the prospective potential of the multifunctional CMC-based hydrogel for applications in wound dressings.