Local Drug Delivery Strategies towards Wound Healing

Antibacterial Properties of Polymeric Membranes Containing Doxycycline for Potential Applications in Foot Ulcer Treatment

Membranes made from biopolymers and loaded with doxycycline were investigated for potential use in the treatment of foot ulcers in diabetic patients. Carboxymethylcellulose (CMC) and chitosan (CHS) membranes were fabricated with 7% glycerol and 1% doxycycline (DOX). Their mechanical and physical properties, biocompatibility, and antimicrobial effects were thoroughly evaluated. The results demonstrated effective antibacterial activity against S. aureus and S. mutans. Based on the mechanical, physical, and hemolytic data, DOX-loaded CMC/CHS/G membranes show promise as a topical wound delivery system.

Dexketoprofen-Loaded Alginate-Grafted Poly(N-vinylcaprolactam)-Based Hydrogel for Wound Healing

All acute and chronic wound management strategies have limitations. Therefore, there is an urgent need to develop new treatment options for wound healing. Hydrogels based on natural polymers offer advantages in wound management because they can reduce patients' pain, fight infection, and carry targeted drugs to speed up the healing process. In this study, we aimed to develop and investigate an alginate-grafted N-vinylcaprolactam-based matrix for a modified release of dexketoprofen (DEX), which is potentially useful in wound healing. Free radical polymerization and grafted techniques were used to prepare thermo-responsive hydrogels. The obtained hydrogels, unloaded hydrogel (HY) and dexketoprofen-loaded hydrogel (DEXHY), were characterized and analyzed. The concentration of DEX encapsulated in the polymer matrix was 4 mg/mL. The IC50 values found for the samples tested by us were 607.4 µg/mL for HY, 950.4 µg/mL for DEXHY, and 2239 µg/mL for DEX. The average value of cell viability (%) after the exposure of cells to DEXHY hydrogel was 75.4%. DEXHY exhibited a very good in vitro wound closure rate, given its ability to modify DEX release kinetics. The hydrogel developed in this study has shown considerable potential to facilitate and even accelerate wound healing, including surgical wounds, by inhibiting the overexpressed inflammation process.

Advancement of Nanomaterials- and Biomaterials-Based Technologies for Wound Healing and Tissue Regenerative Applications

Patients and healthcare systems face significant social and financial challenges due to the increasing number of individuals with chronic external and internal wounds that fail to heal. The complexity of the healing process remains a serious health concern, despite the effectiveness of conventional wound dressings in promoting healing. Recent advancements in materials science and fabrication techniques have led to the development of innovative dressings that enhance wound healing. To further expedite the healing process, novel approaches such as nanoparticles, 3D-printed wound dressings, and biomolecule-infused dressings have emerged, along with cell-based methods. Additionally, gene therapy technologies are being harnessed to generate stem cell derivatives that are more functional, selective, and responsive than their natural counterparts. This review highlights the significant potential of biomaterials, nanoparticles, 3D bioprinting, and gene- and cell-based therapies in wound healing. However, it also underscores the necessity for further research to address the existing challenges and integrate these strategies into standard clinical practice.

NIR-Light Activable 3D Printed Platform Nanoarchitectured with Electrospun Plasmonic Filaments for On Demand Treatment of Infected Wounds

Bacterial infections can lead to severe complications that adversely affect wound healing. Thus, the development of effective wound dressings has become a major focus in the biomedical field, as current solutions remain insufficient for treating complex, particularly chronic wounds. Designing an optimal environment for healing and tissue regeneration is essential. This study aims to optimize a multi-functional 3D printed hydrogel for infected wounds. A dexamethasone (DMX)-loaded electrospun mat, incorporated with gold nanorods (AuNRs), is structured into short filaments (SFs). The SFs are 3D printed into gelatine methacrylate (GelMA) and sodium alginate (SA) scaffold. The photo-responsive AuNRs within SFs significantly enhanced DXM release when exposed to near-infrared (NIR) light. The material exhibits excellent photothermal properties, biocompatibility, and antibacterial activity under NIR irradiation, effectively eliminating Staphylococcus aureus and Escherichia coli in vitro. In vivo, material combined with NIR light treatment facilitate infectes wound healing, killing S. aureus bacteria, reduced inflammation, and induced vascularization. The final materials' shape can be adjusted to the skin defect, release the anti-inflammatory DXM on-demand, provide antimicrobial protection, and accelerate the healing of chronic wounds.

Unfolded protein responses: Dynamic machinery in wound healing

Skin wound healing is a dynamic process consisting of multiple cellular and molecular events that must be tightly coordinated to repair the injured tissue efficiently. The healing pace is decided by the type of injuries, the depth and size of the wounds, and whether wound infections occur. However, aging, comorbidities, genetic factors, hormones, and nutrition also impact healing outcomes. During wound healing, cells undergo robust processes of synthesizing new proteins and degrading multifunctional proteins. This imposes an increasing burden on the endoplasmic reticulum (ER), causing ER stress. Unfolded protein response (UPR) represents a collection of highly conserved stress signaling pathways originated from the ER to maintain protein homeostasis and modulate cell physiology. UPR is known to be beneficial for tissue healing. However, when excessive ER stress exceeds ER's folding potential, UPR pathways trigger cell apoptosis, interrupting tissue regeneration. Understanding how UPR pathways modulate the skin's response to injuries is critical for new interventions toward the control of acute and chronic wounds. Herein, in this review, we focus on the participation of the canonical and noncanonical UPR pathways during different stages of wound healing, summarize the available evidence demonstrating UPR's unique position in balancing homeostasis and pathophysiology of healing tissues, and highlight the understudied areas where therapeutic opportunities may arise.

Transforming Medicine: Cutting-Edge Applications of Nanoscale Materials in Drug Delivery

Since their inception in the early 1960s, the development and use of nanoscale materials have progressed tremendously, and their roles in diverse fields ranging from human health to energy and electronics are undeniable. The application of nanotechnology inventions has revolutionized many aspects of everyday life including various medical applications and specifically drug delivery systems, maximizing the therapeutic efficacy of the contained drugs by means of bioavailability enhancement or minimization of adverse effects. In this review, we utilize the CAS Content Collection, a vast repository of scientific information extracted from journal and patent publications, to analyze trends in nanoscience research relevant to drug delivery in an effort to provide a comprehensive and detailed picture of the use of nanotechnology in this field. We examine the publication landscape in the area to provide insights into current knowledge advances and developments. We review the major classes of nanosized drug delivery systems, their delivery routes, and targeted diseases. We outline the most discussed concepts and assess the advantages of various nanocarriers. The objective of this review is to provide a broad overview of the evolving landscape of current knowledge regarding nanosized drug delivery systems, to outline challenges, and to evaluate growth opportunities. The merit of the review stems from the extensive, wide-ranging coverage of the most up-to-date scientific information, allowing unmatched breadth of landscape analysis and in-depth insights.

Therapeutic Potential of Microneedle Assisted Drug Delivery for Wound Healing: Current State of the Art, Challenges, and Future Perspective

Microneedles (MNs) appear as a transformative and minimally invasive platform for transdermal drug delivery, representing a highly promising strategy in wound healing therapeutics. This technology, entailing the fabrication of micron-scale needle arrays, enables the targeted and efficient delivery of bioactive agents into the epidermal and dermal layers without inducing significant pain or discomfort. The precise penetration of MNs facilitates localized and sustained drug release, which significantly enhances tissue regeneration and accelerates wound closure. Furthermore, MNs can be engineered to encapsulate essential bioactive compounds, including antimicrobial agents, growth factors, and stem cells, which are critical for modulating the wound healing cascade and mitigating infection risk. The biodegradable nature of these MNs obviates the need for device removal, rendering them particularly advantageous in the management of chronic wounds such as diabetic ulcers and pressure sores. The integration of nanotechnology within MNs further augments their drug-loading capacity, stability, and controlled-release kinetics, offering a sophisticated therapeutic modality. This cutting-edge approach has the potential to redefine wound care by optimizing therapeutic efficacy, reducing adverse effects, and enhancing patient adherence. As MN technology advances, its application in wound healing exemplifies a dynamic frontier within biomedical engineering and regenerative medicine.

Local Treatment of Wound Infections: A Review of Clinical Trials from 2013 to 2024

Significance: Management of infection is a critical aspect of wound care. It involves the application of various interventions to treat the wound and prevent the infection from spreading to other parts of the body, which may lead to serious complications, including sepsis. Local treatment of skin wound infections is the favored route of administration, reducing the risk of adverse systemic effects while providing very high therapeutic concentrations at the target site. The purpose of this article was to review clinical trials from 2013 and onward, focusing on local treatment of acute wounds and burns as well as chronic wounds as their primary outcome measurement. Recent Advances: Based on our literature search, 49 clinical trials were focusing on treating infected chronic wounds, and 6 trials studied infection as their primary outcome in acute wounds during the last 10 years. Critical Issues: Currently commercially available local treatments do not prevent the onset of invasive infection. Therefore, there is a need for more effective local therapies. Future Directions: Despite multiple preclinical studies introducing novel and promising strategies in terms of novel antimicrobial agents and delivery methods to prevent and treat skin wound infections locally, many have yet to be tested in a clinical setting. These preclinically tested approaches could still be valuable additions to today's care of infected skin wounds.

Niosome-Based Hydrogel of Quince Extract: A Promising Strategy for Expedited Full-thickness Wound Healing in Rat

BACKGROUND

The regeneration of tissue damage involves a series of molecular and cellular events that can be mediated by various natural compounds. Recent studies have highlighted the anti-inflammatory, anti-ulcer, and skin-protecting properties of Cydonia oblonga (Quince), which are mainly attributed to phenolic compounds. These compounds may have some drawbacks when targeting wound applications, including low bioavailability at the wound site. Moreover, to overcome these limitations, surfactant-based nanovesicular systems have been developed as carriers of such compounds for wound healing.

OBJECTIVE

This study aimed to highlight the possible therapeutic potential of niosome-based hydrogel from Quince extract to stabilize and deliver the related bioactive compounds to full-thickness wounds in rats.

METHODS

The niosomal hydrogel was prepared using a thin-film hydration method with the fruit extract (70% methanol). The formulation was optimized by evaluating size, zeta potential, dispersion index, and drug encapsulation efficiency. Full-thickness wounds were created on the dorsal cervical area of Wistar rats, and histopathological analysis of biopsy specimens was conducted on the 12th day of treatment.

RESULTS

Under the study conditions, niosomal hydrogel displayed good physicochemical stability. Histopathological findings demonstrated that niosomal gel promoted angiogenesis, fibroblast maturation, collagen deposition, keratinization, and epidermal layer formation more effectively than control and hydrogel base. Furthermore, niosomal gel treatment markedly reduced inflammation. The total phenol concentration was determined to be 13.34 ± 0.90 mg gallic acid equivalents per gram of dried extract.

CONCLUSION

The niosomal hydrogel containing C. oblonga extract shows potential as a novel approach for wound healing, warranting further investigation in this field.

Collagen-β-cyclodextrin hydrogels for advanced wound dressings: super-swelling, antibacterial action, inflammation modulation, and controlled drug release

A key strategy in enhancing the efficacy of collagen-based hydrogels involves incorporating polysaccharides, which have shown great promise for wound healing. In this study, semi-interpenetrating polymeric network (semi-IPN) hydrogels comprised of collagen (Col) with the macrocyclic oligosaccharide β-cyclodextrin (β-CD) (20-80 wt.%) were synthesised. Fourier-transform infrared (FTIR) spectroscopy confirmed the successful fabrication of these Col/β-CD hydrogels, evidenced by the presence of characteristic absorption bands, including the urea bond band at ∼1740 cm-1, related with collagen crosslinking. Higher β-CD content was associated with increased crosslinking, higher swelling, and faster gelation. The β-CD content directly influenced the morphology and semi-crystallinity. All Col/β-CD hydrogels displayed superabsorbent properties, enhanced thermal stability, and exhibited slow degradation rates. Mechanical properties were significantly improved with contents higher than β-CD 40 wt.%. These hydrogels inhibited the growth of Escherichia coli bacteria and facilitated the controlled release of agents, such as malachite green, methylene blue, and ketorolac. The chemical composition of the Col/β-CD hydrogels did not induce cytotoxic effects on monocytes and fibroblast cells. Instead, they actively promoted cellular metabolic activity, encouraging cell growth and proliferation. Moreover, cell signalling modulation was observed, leading to changes in the expression of TNF-α and IL-10 cytokines. In summary, the results of this research indicate that these novel hydrogels possess multifunctional characteristics, including biocompatibility, super-swelling capacity, good thermal, hydrolytic, and enzymatic degradation resistance, antibacterial activity, inflammation modulation, and the ability to be used for controlled delivery of therapeutic agents, indicating high potential for application in advanced wound dressings.

Innovative approaches to wound healing: insights into interactive dressings and future directions

The objective of this review is to provide an up-to-date and all-encompassing account of the recent advancements in the domain of interactive wound dressings. Considering the gap between the achieved and desired clinical outcomes with currently available or under-study wound healing therapies, newer more specific options based on the wound type and healing phase are reviewed. Starting from the comprehensive description of the wound healing process, a detailed classification of wound dressings is presented. Subsequently, we present an elaborate and significant discussion describing interactive (unconventional) wound dressings. Latter includes biopolymer-based, bioactive-containing and biosensor-based smart dressings, which are discussed in separate sections together with their applications and limitations. Moreover, recent (2-5 years) clinical trials, patents on unconventional dressings, marketed products, and other information on advanced wound care designs and techniques are discussed. Subsequently, the future research direction is highlighted, describing peptides, proteins, and human amniotic membranes as potential wound dressings. Finally, we conclude that this field needs further development and offers scope for integrating information on the healing process with newer technologies.

Gingerol containing polymeric nanofibers: a healing touch for accelerated wound recovery

OBJECTIVE

In the current research, 6-gingerol (GA)-loaded nanofiber drug delivery system were developed, and their potential usage in wound healing was evaluated.

SIGNIFICANCE

This study investigates the effectiveness of nanofibrous membranes composed of sodium alginate (SA), poly(vinyl alcohol) (PVA), and 6-gingerol (GA) as delivery systems for anti-inflammatory agents in the context of wound dressings.

METHODS

GA-loaded SA/PVA nanofiber was prepared using electrospinning. In vitro characterization of this nanofiber included the examination of comprehensive in vitro characterization, anti-inflammatory and antioxidant activities, cytotoxicity, a scratch tes and in vivo skin test.

RESULTS

GA was extracted from Zingiber officinale, and its successful isolation was confirmed through analyses such as H-NMR, C-NMR. Then GA was electrospuned into the SA/PVA nanofibers, and scanning electron microscopy (SEM) imaging revealed that the fiber diameters of the formulations ranged between 148 nm and 176 nm. Anti-inflammatory and antioxidant studies demonstrated that the effectiveness of GA increased with higher doses; however, this increase was accompanied by decreased cell viability. In vitro release studies revealed that GA exhibited a burst release within the first 8 h, followed by a controlled release, reaching completion within 24 h. Within the scope of in vitro release kinetics, release data are mathematically compatible with the Weibull model with high correlation. The scratch test results indicated that TB2 (%1 GA) promoted epithelialization. Furthermore, it was determined that TB2 (%1 GA) did not cause any irritation.

CONCLUSIONS

As a result, TB2 shows promise as a formulation for wound dressings, offering potential benefits in the field of wound care.

Advancements in wound healing: integrating biomolecules, drug delivery carriers, and targeted therapeutics for enhanced tissue repair

Wound healing, a critical biological process vital for tissue restoration, has spurred a global market exceeding $15 billion for wound care products and $12 billion for scar treatment. Chronic wounds lead to delayed or impaired wound healing. Natural bioactive compounds, prized for minimal side effects, stand out as promising candidates for effective wound healing. In response, researchers are turning to nanotechnology, employing the encapsulation of these agents into drug delivery carriers. Drug delivery system will play a crucial role in enabling targeted delivery of therapeutic agents to promote tissue regeneration and address underlying issues such as inflammation, infection, and impaired angiogenesis in chronic wound healing. Drug delivery carriers offer distinct advantages, exhibiting a substantial ratio of surface area to volume and altered physical and chemical properties. These carriers facilitate sustained and controlled release, proving particularly advantageous for the extended process of wound healing, that typically comprise a diverse range of components, integrating both natural and synthetic polymers. Additionally, they often incorporate bioactive molecules. Despite their properties, including poor solubility, rapid degradation, and limited bioavailability, various natural bioactive agents face challenges in clinical applications. With a global research, emphasis on harnessing nanomaterial for wound healing application, this research overview engages advancing drug delivery technologies to augment the effectiveness of tissue regeneration using bioactive molecules. Recent progress in drug delivery has poised to enhance the therapeutic efficacy of natural compounds in wound healing applications.

Antiseptic pyolytics and warming wet compresses improve the prospect of healing chronic wounds

Infection and suppuration of chronic wounds reduce the effectiveness of their treatment with a course of antibiotics and antiseptics combined with frequently renewed dressings. Therefore, daily short-term procedures of cleaning wounds from purulent-necrotic masses by mechanical methods, including the use of cleansing solutions and necrophage fly larvae, are also part of the general practice of chronic wound treatment. But even they do not always provide rapid healing of chronic wounds. In this connection, it is suggested to supplement the treatment of chronic wounds with preparations dissolving dense pus and wound dressings made in the form of warm moist compresses creating a local greenhouse effect in the wounds. Solutions of 3% hydrogen peroxide and 2–10% sodium bicarbonate heated to a temperature of 37°–45°С, possessing alkaline activity at рН 8.4–8.5 and enriched with dissolved carbon dioxide or oxygen gas (due to overpressure of 0.2 atm were suggested as pyolytic drugs. The first results of the use of pyolytics and warm moist dressings-compresses in the treatment of chronic wounds demonstrate a wound-healing effect. It is suggested to consider sanitizing therapy with pyolytics and warm moist wound dressings-compresses as an alternative to the use of modern cleansing solutions and artificial introduction of larvae of the necrophage fly into the purulent masses of chronic wounds to dissolve dense pus and accelerate the healing process.

Tea polyphenols (TPP) as a promising wound healing agent: TPP exerts multiple and distinct mechanisms at different phases of wound healing in a mouse model

Polyphenols have been widely used to treat various chronic skin diseases because they are beneficial in wound healing and show anti-inflammatory effects, however, the mechanism of action remains ambiguous. Previously, we reported the wound healing capability of tea polyphenols (TPP), the major functional component of tea, in vivo. The current study aimed to address the mechanisms of TPP in wound healing during different phases (inflammation, proliferation and remodeling). During the inflammation phase, TPP reduced the production of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) and inhibited infiltration of neutrophils; during the proliferation phase, TPP promoted the expression of growth factor VEGF-A, which can promote vascular endothelial cell division and induce angiogenesis; TPP improved the morphology of the wound and restored the ratio of type III/I collagens during the remodeling phase, as determined by Masson-trichrome staining and Sirius red staining assays. By tracking the changes in the wound area, TPP and recombinant human epidermal growth factor (rhEGF), rather than povidone-iodine (PVP-I), were able to promote wound healing. These results suggest that TPP plays a pivotal role in all the key stages of wound healing and displays distinct mechanisms from rhEGF, suggesting clinical significance for the future application of TPP as a natural wound healing agent.

Radiosterilized Pig Skin, Silver Nanoparticles and Skin Cells as an Integral Dressing Treatment for Burns: Development, Pre-Clinical and Clinical Pilot Study

Radiosterilized pig skin (RPS) has been used as a dressing for burns since the 1980s. Its similarity to human skin in terms of the extracellular matrix (ECM) allows the attachment of mesenchymal stem cells, making it ideal as a scaffold to create cellularized constructs. The use of silver nanoparticles (AgNPs) has been proven to be an appropriate alternative to the use of antibiotics and a potential solution against multidrug-resistant bacteria. RPS can be impregnated with AgNPs to develop nanomaterials capable of preventing wound infections. The main goal of this study was to assess the use of RPS as a scaffold for autologous fibroblasts (Fb), keratinocytes (Kc), and mesenchymal stem cells (MSC) in the treatment of second-degree burns (SDB). Additionally, independent RPS samples were impregnated with AgNPs to enhance their properties and further develop an antibacterial dressing that was initially tested using a burn mouse model. This protocol was approved by the Research and Ethics Committee of the INRLGII (INR 20/19 AC). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis of the synthesized AgNPs showed an average size of 10 nm and rounded morphology. Minimum inhibitory concentrations (MIC) and Kirby-Bauer assays indicated that AgNPs (in solution at a concentration of 125 ppm) exhibit antimicrobial activity against the planktonic form of S. aureus isolated from burned patients; moreover, a log reduction of 1.74 ± 0.24 was achieved against biofilm formation. The nanomaterial developed with RPS impregnated with AgNPs solution at 125 ppm (RPS-AgNPs125) facilitated wound healing in a burn mouse model and enhanced extracellular matrix (ECM) deposition, as analyzed by Masson's staining in histological samples. No silver was detected by energy-dispersive X-ray spectroscopy (EDS) in the skin, and neither by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in different organs of the mouse burn model. Calcein/ethidium homodimer (EthD-1), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), and scanning electron microscopy (SEM) analysis demonstrated that Fb, Kc, and MSC could attach to RPS with over 95% cell viability. Kc were capable of releasing FGF at 0.5 pg above control levels, as analyzed by ELISA assays. An autologous RPS-Fb-Kc construct was implanted in a patient with SDB and compared to an autologous skin graft. The patient recovery was assessed seven days post-implantation, and the patient was followed up at one, two, and three months after the implantation, exhibiting favorable recovery compared to the gold standard, as measured by the cutometer. In conclusion, RPS effectively can be used as a scaffold for the culture of Fb, Kc, and MSC, facilitating the development of a cellularized construct that enhances wound healing in burn patients.

Wound healing strategies based on nanoparticles incorporated in hydrogel wound patches

The intricate, tightly controlled mechanism of wound healing that is a vital physiological mechanism is essential to maintaining the skin's natural barrier function. Numerous studies have focused on wound healing as it is a massive burden on the healthcare system. Wound repair is a complicated process with various cell types and microenvironment conditions. In wound healing studies, novel therapeutic approaches have been proposed to deliver an effective treatment. Nanoparticle-based materials are preferred due to their antibacterial activity, biocompatibility, and increased mechanical strength in wound healing. They can be divided into six main groups: metal NPs, ceramic NPs, polymer NPs, self-assembled NPs, composite NPs, and nanoparticle-loaded hydrogels. Each group shows several advantages and disadvantages, and which material will be used depends on the type, depth, and area of the wound. Better wound care/healing techniques are now possible, thanks to the development of wound healing strategies based on these materials, which mimic the extracellular matrix (ECM) microenvironment of the wound. Bearing this in mind, here we reviewed current studies on which NPs have been used in wound healing and how this strategy has become a key biotechnological procedure to treat skin infections and wounds.

Nanofiber Scaffolds as Drug Delivery Systems Promoting Wound Healing

Nanofiber scaffolds have emerged as a revolutionary drug delivery platform for promoting wound healing, due to their unique properties, including high surface area, interconnected porosity, excellent breathability, and moisture absorption, as well as their spatial structure which mimics the extracellular matrix. However, the use of nanofibers to achieve controlled drug loading and release still presents many challenges, with ongoing research still exploring how to load drugs onto nanofiber scaffolds without loss of activity and how to control their release in a specific spatiotemporal manner. This comprehensive study systematically reviews the applications and recent advances related to drug-laden nanofiber scaffolds for skin-wound management. First, we introduce commonly used methods for nanofiber preparation, including electrostatic spinning, sol-gel, molecular self-assembly, thermally induced phase separation, and 3D-printing techniques. Next, we summarize the polymers used in the preparation of nanofibers and drug delivery methods utilizing nanofiber scaffolds. We then review the application of drug-loaded nanofiber scaffolds for wound healing, considering the different stages of wound healing in which the drug acts. Finally, we briefly describe stimulus-responsive drug delivery schemes for nanofiber scaffolds, as well as other exciting drug delivery systems.