Layered GelMA/PEGDA Hydrogel Microneedle Patch as an Intradermal Delivery System for Hypertrophic Scar Treatment

Bioprinted platform for parallelized screening of engineered microtissues in vivo

Human engineered tissues hold great promise for therapeutic tissue regeneration and repair. Yet, development of these technologies often stalls at the stage of in vivo studies due to the complexity of engineered tissue formulations, which are often composed of diverse cell populations and material elements, along with the tedious nature of in vivo experiments. We introduce a "plug and play" platform called parallelized host apposition for screening tissues in vivo (PHAST). PHAST enables parallelized in vivo testing of 43 three-dimensional microtissues in a single 3D-printed device. Using PHAST, we screen microtissue formations with varying cellular and material components and identify formulations that support vascular graft-host inosculation and engineered liver tissue function in vivo. Our studies reveal that the cellular population(s) that should be included in engineered tissues for optimal in vivo performance is material dependent. PHAST could thus accelerate development of human tissue therapies for clinical regeneration and repair.

Enhancing vaccine stability in transdermal microneedle platforms

Micron-scale needles, so-called microneedles (MNs) offer a minimally invasive, nearly painless, and user-friendly method for effective intradermal immunization. Maintaining the stability of antigens and therapeutics is the primary challenge in producing vaccine or drug-loaded MNs. The manufacturing of MNs patches involves processes at ambient or higher temperatures and various physio-mechanical stresses that can impact the therapeutic efficacy of sensitive biologics or vaccines. Therefore, it is crucial to develop techniques that safeguard vaccines and other biological payloads within MNs. Despite growing research interest in deploying MNs as an efficient tool for delivering vaccines, there is no comprehensive review that integrates the strategies and efforts to preserve the thermostability of vaccine payloads to ensure compatibility with MNs fabrication. The discussion delves into various physical and chemical approaches for stabilizing antigens in vaccine formulations, which are subsequently integrated into the MNs matrix. The primary focus is to comprehensively examine the challenges associated with the translation of thermostable vaccine MNs for clinical applications while considering a safe, cost-effective approach with a regulatory roadmap. The recent cutting-edge advances facilitating flexible and scalable manufacturing of stabilized MNs patches have been emphasized. In conclusion, the ability to stabilize vaccines and therapeutics for MNs applications could bolster the effectiveness, safety and user-compliance for various drugs and vaccines, potentially offering a substantial impact on global public health.

Therapeutic strategies: Bioactive hydrogels oxidized sodium alginate/strontium/betamethasone for preventing intrauterine adhesion

Intrauterine adhesion (IUA) is an endometrial damage repair disorder that leads to menstrual loss, amenorrhea, and infertility in women; therefore, addressing this dilemma is a critical challenge. In this study, a multifunctional hydrogel, comprising oxidized sodium alginate (OSA), strontium carbonate (SrCO3), and betamethasone 21-phosphate sodium (BSP), was formulated to facilitate angiogenesis, reduce fibrosis, and support tissue repair in the treatment of IUA. The composite hydrogels showed significant bioactivity on human endometrial stromal cells (HESCs) and human umbilical vein endothelial cells (HUVECs), promoting the injured HESCs repair, reversing the degree of fibrosis to a certain extent, and enhancing the proliferation and migration of HUVECs. These results were also verified in the IUA model of sexually mature female rats. Compared with the model group, the selection of the appropriate hydrogel significantly increased endometrial thickness (p < 0.01), the number of glands (p < 0.001), decreased the degree of fibrosis (p < 0.05), and Vimentin (p < 0.01), CK19 (p < 0.01), CD31 (p < 0.01), and Ki67 (p < 0.01) molecular expression increased remarkably. In summary, in situ injection of this multifunctional hydrogel into the uterine cavity not only serves as a physical barrier, isolating the damaged endometrium, but also gradually releases drugs as the hydrogel degrades. This multifunctional hydrogel promotes endometrial proliferation and angiogenesis while reducing fibrosis, and provides therapeutic strategies for patients with clinical IUA.

The role of macrophages in hypertrophic scarring: molecular to therapeutic insights

Hypertrophic Scar (HS) is a common fibrotic disease of the skin, usually caused by injury to the deep dermis due to trauma, burns, or surgical injury. The main feature of HS is the thickening and hardening of the skin, often accompanied by itching and pain, which seriously affects the patient's quality of life. Macrophages are involved in all stages of HS genesis through phenotypic changes. M1-type macrophages primarily function in the early inflammatory phase by secreting pro-inflammatory factors, while M2-type macrophages actively contribute to tissue repair and fibrosis. Despite advances in understanding HS pathogenesis, the precise mechanisms linking macrophage phenotypic changes to fibrosis remain incompletely elucidated. This review addresses these gaps by discussing the pathological mechanisms of HS formation, the phenotypic changes of macrophages at different stages of HS formation, and the pathways through which macrophages influence HS progression. Furthermore, emerging technologies for HS treatment and novel therapeutic strategies targeting macrophages are highlighted, offering potential avenues for improved prevention and treatment of HS.

A Narrative Review of Bioactive Hydrogel Microspheres: Ingredients, Modifications, Fabrications, Biological Functions, and Applications

Hydrogel microspheres are important in regenerative medicine and tissue engineering, acting as cargos of cells, drugs, growth factors, bio-inks for 3D printing, and medical devices. The antimicrobial and anti-inflammatory characteristics of hydrogel microspheres are good for treating injured tissues. However, the biological properties of hydrogel microspheres should be modified for optimal treatment of various body parts with different physiological and biochemical environments. In addition, specific preparation methods are required to produce customized hydrogel microspheres with different shapes and sizes for various clinical applications. Herein, the advances in hydrogel microspheres for biomedical applications are reviewed. Synthesis methods for hydrogel precursor solutions, manufacturing methods, and strategies for enhancing the biological functions of these hydrogel microspheres are described. The involvement of bioactive hydrogel microspheres in tissue repair is also discussed. This review anticipates fostering more insights into the design, production, and application of hydrogel microspheres in biomedicine.

Skin microincision technique to enhance drug penetration for the treatment of keloid and hypertrophic scars

The synergistic effect of corticosteroids and 5-fluorouracil (5-FU) for the treatment of pathological scarring is widely documented. While topical administration can be a painless, convenient way to convey the two active ingredients, physical enhancement techniques such as microneedling are required to deepen their skin penetration and achieve the therapeutic effect. A novel approach to keloid and scar treatment is given by microincision, i.e., micrometric-sized columnar perforations which allow the drugs to diffuse into the skin and promote tissue proliferation in a more physiological structure. Combining the delivery of triamcinolone acetonide (TAC) and 5-FU with microincision is an innovative approach that could improve the speed and efficacy of regenerative treatments. This study evaluated the effectiveness of the skin treatment with a device combining microincisions and photobiomodulation, in the skin permeation of a combination of TAC and 5-FU. Increasing treatment times (4, 6, and 8 min) led to higher drug penetration compared to intact skin, with a more noticeable effect for 5-FU compared to TAC. Specifically, all treatment durations were significantly more effective (p < 0.05) than the control for 5-FU, while TAC showed less variation between treatments. Moreover, it was shown that in-vitro, the permeation improvement given by the red-light treatment was mainly due to the mechanical massage, which pushed the actives into the microchannels created by the treatment. The application of prolonged skin microincision times ensured much higher skin permeation of both TAC and 5-FU compared to microneedling on healthy excised skin.

Leveraging Microneedles for Raised Scar Management

Disruption of the molecular pathways during physiological wound healing can lead to raised scar formation, characterized by rigid, thick scar tissue with associated symptoms of pain and pruritus. A key mechanical factor in raised scar development is excessive tension at the wound site. Recently, microneedles (MNs) have emerged as promising tools for scar management as they engage with scar tissue and provide them with mechanical off-loading from both internal and external sources. This review explores the mechanisms by which physical intervention of drug-free MNs alleviates mechanical tension on fibroblasts within scar tissue, thereby promoting tissue remodeling and reducing scar severity. Additionally, the role of MNs as an efficient cargo delivery system for the controlled and sustained release of a wide range of therapeutic agents into scar tissue is highlighted. By penetrating scar tissue, MNs facilitate controlled and sustained localized drug administration to modulate inflammation and fibroblastic cell growth. Finally, the remaining challenges and the future perspective of the field have been highlighted.

Emerging biomedical technologies for scarless wound healing

Complete wound healing without scar formation has attracted increasing attention, prompting the development of various strategies to address this challenge. In clinical settings, there is a growing preference for emerging biomedical technologies that effectively manage fibrosis following skin injury, as they provide high efficacy, cost-effectiveness, and minimal side effects compared to invasive and costly surgical techniques. This review gives an overview of the latest developments in advanced biomedical technologies for scarless wound management. We first introduce the wound healing process and key mechanisms involved in scar formation. Subsequently, we explore common strategies for wound treatment, including their fabrication methods, superior performance and the latest research developments in this field. We then shift our focus to emerging biomedical technologies for scarless wound healing, detailing the mechanism of action, unique properties, and advanced practical applications of various biomedical technology-based therapies, such as cell therapy, drug therapy, biomaterial therapy, and synergistic therapy. Finally, we critically assess the shortcomings and potential applications of these biomedical technologies and therapeutic methods in the realm of scar treatment.

Prevention of early thrombosis in transplanted vein model by encapsulation with tirofiban microneedle drug delivery system

Early thrombosis following coronary artery bypass grafting (CABG) surgery leads to perioperative myocardial infarction, which causes difficulties for clinicians and patients. Moreover, once perioperative myocardial infarction occurs, the mortality rate is extremely high. In recent years, microneedle (MN) drug delivery systems have become a research hotspot with broad clinical application prospects. These systems are capable of achieving sustained, safe, and painless local drug release. In cardiovascular applications, MNs maximize local anticoagulant effects, inhibit endometrial hyperplasia, and reduce systemic side effects. We speculate that a MN drug delivery system can be used to target transplanted veins to inhibit their thrombosis and reduce the incidence of perioperative myocardial infarction after CABG surgery. Therefore, this study developed a hyaluronic acid MN patch loaded with tirofiban and conducted preliminary physicochemical tests. The safety, efficacy, biocompatibility, and targeting of the MN system were evaluated usingin vitroandin vivoexperiments using a jugular vein transplantation model. The results indicate that the MN system has excellent physical properties, safety, effectiveness, biocompatibility, and strong targeting, which can effectively inhibit early local thrombus formation. In addition, the observation of early postoperative endometrial hyperplasia activation provides a foundation for future research.

Research trends and hot topics of wearable sensors in wound care over past 18 years: A bibliometric analysis

Objective

This study determined the development trends, analyzed collaboration networks, and identified research hotspots in the field of wearable sensors for wound care from 2007 to 2024 using a rigorous bibliometric analysis approach.

Methods

Bibliometric and scientometric analyses were performed utilizing data sourced from the Web of Science Core Collection database. This study examined publication trends, contributions from various countries and institutions, author productivity, keyword prevalence, and citation patterns to discern research hotspots and potential future avenues in the application of wearable sensors for wound care.

Results

This study included 1177 articles, which demonstrated a marked increase in publications since 2016 and underscores the burgeoning interest in wearable sensors for wound care. China and the United States have emerged as prominent contributors to the research field, exhibiting numerous international collaborations. An analysis of keywords and citation bursts highlighted wound healing, hydrogels, and sensors as the key research foci with recent trends shifting towards the integration of wearable technology with advanced materials and artificial intelligence for advanced wound management. The research landscape is characterized by a diverse network of international collaborations and an emphasis on interdisciplinary approaches that integrate materials science, sensor technology, and clinical applications.

Conclusion

The utilization of wearable sensors in wound care constitutes a rapidly progressing area of research, garnering significant interest and promising avenues for future advances. The integration of wearable sensors with advanced materials and AI technologies presents a frontier of opportunity for innovating wound care methodologies, enhancing patient outcomes, and optimizing the allocation of healthcare resources.

Advanced Wound Healing and Scar Reduction Using an Innovative Anti-ROS Polysaccharide Hydrogel with Recombinant Human Collagen Type III

Excessive fibrotic scar formation during skin defect repair poses a formidable challenge, impeding the simultaneous acceleration of wound healing and prevention of scar formation and hindering the restoration of skin integrity and functionality. Drawing inspiration from the structural, compositional, and biological attributes of skin, we developed a hydrogel containing modified recombinant human collagen type III and thiolated hyaluronic acid to address the challenges of regenerating skin appendages and improving the recovery of skin functions after injury by reducing fibrotic scarring. The hydrogel displayed favorable biocompatibility, antioxidant properties, angiogenic potential, and fibroblast migration stimulation in vitro. In a rat full-layer defect model, it reduced inflammation, promoted microvascular formation, and significantly enhanced the wound healing speed and effectiveness. Additionally, by upregulating fibrosis-associated genes, such as TGFB1, it facilitated collagen accumulation and a beneficial balance between type I and type III collagen, potentially expediting skin regeneration and functional recovery. In conclusion, the utilization of rhCol III-HS demonstrated considerable potential as a wound dressing, offering a highly effective strategy for the restoration and rejuvenation of complete skin defects.

Polymeric Microneedle Drug Delivery Systems: Mechanisms of Treatment, Material Properties, and Clinical Applications—A Comprehensive Review

Our comprehensive review plunges into the cutting-edge advancements of polymeric microneedle drug delivery systems, underscoring their transformative potential in the realm of transdermal drug administration. Our scrutiny centers on the substrate materials pivotal for microneedle construction and the core properties that dictate their efficacy. We delve into the distinctive interplay between microneedles and dermal layers, underscoring the mechanisms by which this synergy enhances drug absorption and precision targeting. Moreover, we examine the acupoint–target organ–ganglion nexus, an innovative strategy that steers drug concentration to specific targets, offering a paradigm for precision medicine. A thorough analysis of the clinical applications of polymeric microneedle systems is presented, highlighting their adaptability and impact across a spectrum of therapeutic domains. This review also accentuates the systems’ promise to bolster patient compliance, attributed to their minimally invasive and painless mode of drug delivery. We present forward-looking strategies aimed at optimizing stimulation sites to amplify therapeutic benefits. The anticipation is set for the introduction of superior biocompatible materials with advanced mechanical properties, customizing microneedles to cater to specialized clinical demands. In parallel, we deliberate on safety strategies aimed at boosting drug loading capacities and solidifying the efficacy of microneedle-based therapeutics. In summation, this review accentuates the pivotal role of polymeric microneedle technology in contemporary healthcare, charting a course for future investigative endeavors and developmental strides within this burgeoning field.

Polymeric Microneedle Drug Delivery Systems: Mechanisms of Treatment, Material Properties, and Clinical Applications-A Comprehensive Review

Our comprehensive review plunges into the cutting-edge advancements of polymeric microneedle drug delivery systems, underscoring their transformative potential in the realm of transdermal drug administration. Our scrutiny centers on the substrate materials pivotal for microneedle construction and the core properties that dictate their efficacy. We delve into the distinctive interplay between microneedles and dermal layers, underscoring the mechanisms by which this synergy enhances drug absorption and precision targeting. Moreover, we examine the acupoint-target organ-ganglion nexus, an innovative strategy that steers drug concentration to specific targets, offering a paradigm for precision medicine. A thorough analysis of the clinical applications of polymeric microneedle systems is presented, highlighting their adaptability and impact across a spectrum of therapeutic domains. This review also accentuates the systems' promise to bolster patient compliance, attributed to their minimally invasive and painless mode of drug delivery. We present forward-looking strategies aimed at optimizing stimulation sites to amplify therapeutic benefits. The anticipation is set for the introduction of superior biocompatible materials with advanced mechanical properties, customizing microneedles to cater to specialized clinical demands. In parallel, we deliberate on safety strategies aimed at boosting drug loading capacities and solidifying the efficacy of microneedle-based therapeutics. In summation, this review accentuates the pivotal role of polymeric microneedle technology in contemporary healthcare, charting a course for future investigative endeavors and developmental strides within this burgeoning field.

Swellable Microneedles in Drug Delivery and Diagnostics

This manuscript explores the transformative potential of swellable microneedles (MNs) in drug delivery and diagnostics, addressing critical needs in medical treatment and monitoring. Innovations in hydrogel-integrated MN arrays facilitate controlled drug release, thereby expanding treatment options for chronic diseases and conditions that require precise dosage control. The review covers challenges, such as scalability, patient compliance, and manufacturing processes, as well as achievements in advanced manufacturing, biocompatibility, and versatile applications. Nonetheless, limitations in physiological responsiveness and long-term stability remain, necessitating further research in material innovation and integration with digital technologies. Future directions focus on expanding biomedical applications, material advancements, and regulatory considerations for widespread clinical adoption.

In Vitro Investigation of Vocal Fold Cellular Response to Variations in Hydrogel Porosity and Elasticity

Tissue regeneration is intricately influenced by the dynamic interplay between the physical attributes of tissue engineering scaffolds and the resulting biological responses. A tunable microporous hydrogel system was engineered using gelatin methacryloyl (GelMA) and polyethylene glycol diacrylate (PEGDA), with polyethylene glycol (PEG) serving as a porogen. Through systematic variation of PEGDA molecular weights, hydrogels with varying mechanical and architectural properties were obtained. The objective of the present study was to elucidate the impact of substrate mechanics and architecture on the immunological and reparative activities of vocal fold tissues. Mechanical characterization of the hydrogels was performed using tensile strength measurements and rheometry. Their morphological properties were investigated using scanning electron microscopy (SEM) and confocal microscopy. A series of biological assays were conducted. Cellular morphology, differentiation, and collagen synthesis of human vocal fold fibroblasts (hVFFs) were evaluated using immunostaining. Fibroblast proliferation was studied using the WST-1 assay, and cell migration was investigated via the Boyden chamber assay. Macrophage polarization and secretions were also examined using immunostaining and ELISA. The results revealed that increasing the molecular weight of PEGDA from 700 Da to 10,000 Da resulted in decreased hydrogel stiffness, from 62.6 to 8.8 kPa, and increased pore dimensions from approximately 64.9 to 137.4 μm. Biological evaluations revealed that hydrogels with a higher stiffness promoted fibroblast proliferation and spreading, albeit with an increased propensity for fibrosis, as indicated by a surge in myofibroblast differentiation and collagen synthesis. In contrast, hydrogels with greater molecular weights had a softer matrix with expanded pores, enhancing cellular migration and promoting an M2 macrophage phenotype conducive to tissue healing. The findings show that the hydrogels formulated with a PEGDA molecular weight of 6000 Da are best among the hydrogels considered for vocal fold repair. The microporous hydrogels could be tuned to serve in other tissue engineering applications.

Unveiling the versatility of gelatin methacryloyl hydrogels: a comprehensive journey into biomedical applications

Gelatin methacryloyl (GelMA) hydrogels have gained significant recognition as versatile biomaterials in the biomedical domain. GelMA hydrogels emulate vital characteristics of the innate extracellular matrix by integrating cell-adhering and matrix metalloproteinase-responsive peptide motifs. These features enable cellular proliferation and spreading within GelMA-based hydrogel scaffolds. Moreover, GelMA displays flexibility in processing, as it experiences crosslinking when exposed to light irradiation, supporting the development of hydrogels with adjustable mechanical characteristics. The drug delivery landscape has been reshaped by GelMA hydrogels, offering a favorable platform for the controlled and sustained release of therapeutic actives. The tunable physicochemical characteristics of GelMA enable precise modulation of the kinetics of drug release, ensuring optimal therapeutic effectiveness. In tissue engineering, GelMA hydrogels perform an essential role in the design of the scaffold, providing a biomimetic environment conducive to cell adhesion, proliferation, and differentiation. Incorporating GelMA in three-dimensional printing further improves its applicability in drug delivery and developing complicated tissue constructs with spatial precision. Wound healing applications showcase GelMA hydrogels as bioactive dressings, fostering a conducive microenvironment for tissue regeneration. The inherent biocompatibility and tunable mechanical characteristics of GelMA provide its efficiency in the closure of wounds and tissue repair. GelMA hydrogels stand at the forefront of biomedical innovation, offering a versatile platform for addressing diverse challenges in drug delivery, tissue engineering, and wound healing. This review provides a comprehensive overview, fostering an in-depth understanding of GelMA hydrogel's potential impact on progressing biomedical sciences.

Preparation of Compound Salvia miltiorrhiza-Blumea balsamifera Nanoemulsion Gel and Its Effect on Hypertrophic Scars in the Rabbit Ear Model

Hypertrophic scars (HS) still remain an urgent challenge in the medical community. Traditional Chinese medicine (TCM) has unique advantages in the treatment of HS. However, due to the natural barrier of the skin, it is difficult for the natural active components of TCM to more effectively penetrate the skin and exert therapeutic effects. Therefore, the development of an efficient drug delivery system to facilitate enhanced transdermal absorption of TCM becomes imperative for its clinical application. In this study, we designed a compound Salvia miltiorrhiza-Blumea balsamifera nanoemulsion gel (CSB-NEG) and investigated its therapeutic effects on rabbit HS models. The prescription of CSB-NEG was optimized by single-factor, pseudoternary phase diagram, and central composite design experiments. The results showed that the average particle size and PDI of the optimized CSB-NE were 46.0 ± 0.2 nm and 0.222 ± 0.004, respectively, and the encapsulation efficiency of total phenolic acid was 93.37 ± 2.56%. CSB-NEG demonstrated excellent stability and skin permeation in vitro and displayed a significantly enhanced ability to inhibit scar formation compared to the CSB physical mixture in vivo. After 3 weeks of CSB-NEG treatment, the scar appeared to be flat, pink, and flexible. Furthermore, this treatment also resulted in a decrease in the levels of the collagen I/III ratio and TGF-β1 and Smad2 proteins while simultaneously promoting the growth and remodeling of microvessels. These findings suggest that CSB-NEG has the potential to effectively address the barrier properties of the skin and provide therapeutic benefits for HS, offering a new perspective for the prevention and treatment of HS.

Injectable and Photocurable Gene Scaffold Facilitates Efficient Repair of Spinal Cord Injury

RNA interference-based gene therapy has led to a strategy for spinal cord injury (SCI) therapy. However, there have been high requirements regarding the optimal gene delivery vector for siRNA-based SCI gene therapy. Here, we developed an injectable and photocurable lipid nanoparticle GelMA (PLNG) hydrogel scaffold for controlled dual siRNA delivery at the SCI wound site. The prepared PLNG scaffold could efficiently protect and retain the bioactivity of the siRNA nanocomplex. It facilitated sustainable siRNA release along with degradation in 7 days. After loading dual siRNA targeting phosphatase and tensin homologue (PTEN) and macrophage migration inhibitory factor (MIF) simultaneously, the locally administered siRNAs/PLNG scaffold efficiently improved the Basso mouse scale (BMS) score and recovered ankle joint movement and plantar stepping after treatment with only three doses. We further proved that the siRNAs/PLNG scaffold successfully regulated the activities of neurons, microglia, and macrophages, thus promoting neuron axon regeneration and remyelination. The protein array results suggested that the siRNAs/PLNG scaffold could increase the expression of growth factors and decrease the expression of inflammatory factors to regulate neuroinflammation in SCI and create a neural repair environment. Our results suggested that the PLNG scaffold siRNA delivery system is a potential candidate for siRNA-based SCI therapy.

Hydrogel Loaded with Components for Therapeutic Applications in Hypertrophic Scars and Keloids

Hypertrophic scars and keloids are common fibroproliferative diseases following injury. Patients with pathologic scars suffer from impaired quality of life and psychological health due to appearance disfiguration, itch, pain, and movement disorders. Recently, the advancement of hydrogels in biomedical fields has brought a variety of novel materials, methods and therapeutic targets for treating hypertrophic scars and keloids, which exhibit broad prospects. This review has summarized current research on hydrogels and loaded components used in preventing and treating hypertrophic scars and keloids. These hydrogels attenuate keloid and hypertrophic scar formation and progression by loading organic chemicals, drugs, or bioactive molecules (such as growth factors, genes, proteins/peptides, and stem cells/exosomes). Among them, smart hydrogels (a very promising method for loading many types of bioactive components) are currently favoured by researchers. In addition, combining hydrogels and current therapy (such as laser or radiation therapy, etc.) could improve the treatment of hypertrophic scars and keloids. Then, the difficulties and limitations of the current research and possible suggestions for improvement are listed. Moreover, we also propose novel strategies for facilitating the construction of target multifunctional hydrogels in the future.

Microneedle-mediated drug delivery for scar prevention and treatment

Scars are an inevitable natural outcome of most wound healing processes and affect skin functions, leading to cosmetic, psychological and social problems. Several strategies, including surgery, radiation, cryotherapy, laser therapy, pressure therapy and corticosteroids, can be used to either prevent or treat scars. However, these strategies are ineffective, have side effects and are typically expensive. Microneedle (MN) technology is a powerful, minimally invasive platform for transdermal drug delivery. This review discusses the most recent progress in MN-mediated drug delivery to prevent and treat pathological scars (hypertrophic and keloids). A comprehensive overview of existing challenges and future perspectives is also provided.