Smart Microneedles for Therapy and Diagnosis

Enhancing melanoma therapy with hydrogel microneedles

Melanoma is highly invasive and resistant to conventional treatments, accounting for nearly 75% of skin cancer-related deaths globally. Traditional therapies, such as chemotherapy and immunotherapy, often exhibit limited efficacy and are associated with significant side effects due to systemic drug exposure. Microneedles (MNs), as an emerging drug delivery system, offer multiple advantages, including safety, painlessness, minimal invasiveness, and controlled drug release. Among these, hydrogel microneedles (HMNs) stand out due to their extracellular matrix-like structure and swelling-induced continuous hydrogel channels, which enable the direct delivery of therapeutic agents into the tumor microenvironment (TME). This approach enhances drug bioavailability while reducing systemic toxicity, establishing HMNs as a promising platform for melanoma treatment. This review highlights recent advancements in HMNs for melanoma therapy, focusing on their applications in biomarker extraction for early diagnosis and their role in supporting multimodal treatment strategies, such as chemotherapy, immunotherapy, phototherapy, targeted therapy, and combination therapy. Furthermore, the current matrix materials and fabrication techniques for HMNs are discussed. Finally, the limitations of HMNs in melanoma treatment are critically analyzed, and recommendations for future research and development are provided.

Microfluidic Synthesis of Magnetic Nanoparticles for Biomedical Applications

Magnetic nanoparticles have attracted great attention and become promising candidates in the biomedicine field due to their special physicochemical properties. They are generally divided into metallic and non-metallic magnetic nanoparticles, according to their compositions. Both of the two types have shown practical values in biomedicine applications, such as drug delivery, biosensing, bioimaging, and so on. Research efforts are devoted to the improvement of synthesis strategies to achieve magnetic nanoparticles with controllable morphology, diverse composition, active surface, or multiple functions. Taking high repeatability, programmable operation, precise fluid control, and simple device into account, the microfluidics system can expand the production scale and develop magnetic nanoparticles with desired features. This review will first describe different classifications of promising magnetic nanoparticles, followed by the advancements in microfluidic synthesis and the latest biomedical applications of these magnetic nanoparticles. In addition, the challenges and prospects of magnetic nanoparticles in the biomedical field are also discussed.

Advancing frontiers in skin offensive odor management: from innovative diagnostics to cutting-edge treatments and emerging technologies

Skin bromhidrosis, commonly referred to as body odor, is caused by the microbial breakdown of sweat, leading to the formation of volatile organic compounds (VOCs) that result in unpleasant odors. While body odor is a natural consequence of sweat production, excessive or persistent odor can significantly affect quality of life, causing social stigma and psychological distress. Traditional approaches to managing body odor, such as antiperspirants and deodorants, have limitations, necessitating the development of more advanced diagnostic tools and treatments. This review aims to explore recent advancements in the diagnosis and treatment of skin offensive odor, focusing on cutting-edge technologies and novel approaches. It highlights the interplay of the skin microbiome, sweat gland activity, and external factors in odor formation and investigates innovative solutions for long-term odor management. Emerging diagnostic techniques, such as electronic nose (E-nose) technology, gas chromatography-mass spectrometry (GC-MS), and next-generation sequencing (NGS), enable precise detection and analysis of odor-causing VOCs and microbial profiles. These tools facilitate a deeper understanding of the pathophysiology of odor production. Treatment innovations include nanotechnology-based antimicrobials (e.g., silver and zinc oxide nanoparticles), probiotic formulations for microbiome modulation, and odor-neutralizing compounds such as cyclodextrins and enzymatic neutralizers. Advanced delivery systems, including microneedle patches and nanoencapsulation, enable targeted, sustained release of active ingredients. Additionally, systemic approaches like oral probiotics and dietary interventions offer complementary strategies for managing body odor. The integration of novel diagnostics with innovative topical and systemic treatments offers promising avenues for more effective and personalized management of skin offensive odor. These advancements pave the way for improved quality of life for individuals affected by bromhidrosis, with potential for widespread application in personal care and medical contexts. Clinical trial number: Not applicable.

Engineering exosomes and exosome-like nanovesicles for improving tissue targeting and retention

Exosomes are natural nano-size particles secreted by human cells, containing numerous bioactive cargos. Serving as crucial mediators of intercellular communication, exosomes are involved in many physiological and pathological processes, such as inflammation, tissue injury, cardiovascular diseases, tumorigenesis and tumor development. Exosomes have exhibited promising results in the diagnosis and treatment of cancer, cardiovascular diseases and others. They are a rapidly growing class of drug delivery vehicles with many advantages over conventional synthetic carriers. Exosomes used in therapeutic applications encounter several challenges, such as the lack of tissue targeting capabilities and short residence time. In this review, we discuss recent advances in exosome engineering to improve tissue targeting and describe the current types of engineered exosome-like nanovesicles, and summarize their preclinical applications in the treatment of diseases. Further, we also highlight the latest engineering strategies developed to extend exosomes retention time in vivo and exosome-like nanovesicles.

Microneedle drug delivery system based on hyaluronic acid for improving therapeutic efficiency of hypertrophic scars

Hypertrophic scar (HS) is a disease with excessive skin fibrosis and collagen disorder, which is generally caused by abnormal wound repair process after burn and trauma. Although intralesional injection of 5-fluorouracil (5-Fu) has been used in clinical treatment of HS, the patients' compliance of injection treatment is poor. In this study, a double-layer dissolution microneedle (MN) containing asiaticoside (AS) and 5-Fu was designed for the treatment of HS. Biological macromolecules materials affected the formability, drug release, and hardness of MNs. Therefore, several types of biomacromolecules, including hyaluronic acid (HA), chitosan, and sodium alginate, which could be used to prepare MNs, underwent prescription optimization experiments and the optimized MN prescriptions were obtained. In vitro characterization showed that the MN was sufficient to deliver drugs through the skin. Animal in vivo experiments showed that AS and 5-Fu can synergistically treat HS, significantly reduce the abnormal proliferation of fibroblasts and collagen fiber deposition, and down-regulated collagen I (Col I) and transforming growth factor-β1 (TGF-β1) expression. In conclusion, the micro-needle designed in this study has great prospects in the treatment of HS.

MXene-Integrated Responsive Hydrogel Microneedles for Oral Ulcers Healing

Glucocorticoids such as dexamethasone have shown promising therapeutic effects in conquering oral ulcers. Challenges in this area are focused on enhancing the localized curative effects and responsive release. Herein, we presented a novel MXene-integrated responsive hydrogel microneedle delivering dexamethasone to promote the healing of oral ulceration. By loading MXene, the hydrogel microneedles enable NIR (Near Infrared)-responsive release of the inner dexamethasone for inflammation control and tissue regeneration. In addition, the MXene-induced local hyperthermia could inhibit the bacteria, preventing the possible infection of ulcer lesions in the oral cavity. Based on these features, we demonstrated that our strategy could relieve local inflammation, promote tissue reconstruction, and accelerate wound healing in rat oral ulcer models. Overall, these NIR-responsive MXene-integrated hydrogel microneedles show significant promise in promoting ulcer healing and bring new ways for oral disease treatment.

Developing mRNA Nanomedicines with Advanced Targeting Functions

The emerging messenger RNA (mRNA) nanomedicines have sprung up for disease treatment. Developing targeted mRNA nanomedicines has become a thrilling research hotspot in recent years, as they can be precisely delivered to specific organs or tissues to enhance efficiency and avoid side effects. Herein, we give a comprehensive review on the latest research progress of mRNA nanomedicines with targeting functions. mRNA and its carriers are first described in detail. Then, mechanisms of passive targeting, endogenous targeting, and active targeting are outlined, with a focus on various biological barriers that mRNA may encounter during in vivo delivery. Next, emphasis is placed on summarizing mRNA-based organ-targeting strategies. Lastly, the advantages and challenges of mRNA nanomedicines in clinical translation are mentioned. This review is expected to inspire researchers in this field and drive further development of mRNA targeting technology.

Advances in adhesion of microneedles for bioengineering

Microneedles have provided promising platforms in various fields thanks to their safety, painlessness, minimal invasiveness and ease of operation. The excellent adhesion of microneedles is the key characteristic to achieve long-term and comfortable treatment. However, a complex environment, such as the roughness of skin, various bodily fluids in vivo, and the movement of the body, presents great challenges to the adhesion characteristics of microneedles. This review mainly reports the remarkable adhesion properties of microneedles based on interlocking by shape effects, chemical bonds, and suction forces. Firstly, the main mechanisms of adhesion and various types of microneedles are introduced, with an emphasis on the progress in adhesive microneedles. Combined with the preparation and application of microneedles, the challenges and future trends of adhesive microneedles are discussed.

Smart drug delivery and responsive microneedles for wound healing

Wound healing is an ongoing concern for the medical community. The limitations of traditional dressings are being addressed by materials and manufacturing technology. Microneedles (MNs) are a novel type of drug delivery system that has been widely used in cancer therapy, dermatological treatment, and insulin and vaccine delivery. MNs locally penetrate necrotic tissue, eschar, biofilm and epidermis into deep tissues, avoiding the possibility of drug dilution and degradation and greatly improving administration efficiency with less pain. MNs represent a new direction for wound treatment and transdermal delivery. In this study, we summarise the skin wound healing process and the mechanical stimulation of MNs in the context of the wound healing process. We also introduce the structural design and manufacture of MNs. Subsequently, MNs are categorised according to the loaded drugs, where the design of the MNs according to the traumatic biological/biochemical microenvironment (pH, glucose, and bacteria) and the physical microenvironment (temperature, light, and ultrasound) is emphasised. Finally, the advantages of MNs are compared with traditional drug delivery systems and their prospects are discussed.

Biodegradable polymeric insulin microneedles - a design and materials perspective review

Microneedle (MN) delivery devices are more accepted by people than regular traditional needle injections (e.g. vaccination) due to their simplicity and adaptability. Thus, patients of chronic diseases like diabetes look for alternative pain-free treatment regimens circumventing regular subcutaneous injections. Insulin microneedles (INS-MNs) are a thoughtfully researched topic (1) to overcome needle phobia in patients, (2) for controlled delivery of the peptide, (3) decreasing the frequency of drug administration, (4) to ease the drug administration procedure, and (5) thus increasing patient adherence to the treatment dosage regimes. MNs physically disrupt the hard outer skin layer to create minuscule pores for insulin (INS) to pass through the dermal capillaries into the systemic circulation. Biodegradable polymeric MNs are of greater significance for INS and vaccine delivery than silicon, metal, glass, or non-biodegradable polymeric MNs due to their ease of fabrication, mass production, cost-effectiveness, and bioerodability. In recent years, INS-MNs have been researched to deliver INS through the transdermal implants, buccal mucosa, stomach wall, intestinal mucosal layers, and colonic mucosa apart from the usual transdermal delivery. This review focuses on the design characteristics and the applications of biodegradable/dissolvable polymeric INS-MNs in transdermal, intra-oral, gastrointestinal (GI), and implantable delivery. The prospective approaches to formulate safe, controlled-release INS-MNs were highlighted. Biodegradable/dissolvable polymers, their significance, their impact on MN morphology, and INS release characteristics were outlined. The developments in biodegradable polymeric INS-MN technology were briefly discussed. Bio-erodible polymer selection, MN fabrication and evaluation factors, and other design aspects were elaborated.

Microneedles as transdermal drug delivery system for enhancing skin disease treatment

Microneedles (MNs) serve as a revolutionary paradigm in transdermal drug delivery, heralding a viable resolution to the formidable barriers presented by the cutaneous interface. This review examines MNs as an advanced approach to enhancing dermatological pathology management. It explores the complex dermis structure and highlights the limitations of traditional transdermal methods, emphasizing MNs' advantage in bypassing the stratum corneum to deliver drugs directly to the subdermal matrix. The discourse outlines the diverse typologies of MNs, including solid, coated, hollow, hydrogel, and dissolvable versions. Each type is characterized by its unique applications and benefits. The treatise details the deployment of MNs in the alleviation of cutaneous cancers, the administration of inflammatory dermatoses such as psoriasis and atopic dermatitis, and their utility in wound management. Additionally, the paper contemplates the prospects of MNs within the realm of aesthetic dermatology and the burgeoning market traction of cosmetic MN formulations. The review summarizes the scientific and commercial challenges to the clinical adoption of MN therapeutics, including dosage calibration, pharmacodynamics, biocompatibility, patient compliance, sterilization, mass production, and regulatory oversight. It emphasizes the need for ongoing research, innovation, and regulatory harmonization to overcome these obstacles and fully realize MNs' potential in treating skin diseases and improving patient welfare.

Emerging Technological Advancement for Chronic Wound Treatment and Their Role in Accelerating Wound Healing

Chronic wounds are a major healthcare burden and may severely affect the social, mental, and economic status of the patients. Any impairment in wound healing stages due to underlying factors leads to a prolonged healing time and subsequently to chronic wounds. Traditional approaches for the treatment of chronic wounds include dressing free local therapy, dressing therapy, and tissue engineering based scaffold therapies. However, traditional therapies need improvisation and have been advanced through breakthrough technologies. The present review spans traditional therapies and further gives an extensive account of advancements in the treatment of chronic wounds. Cutting edge technologies, such as 3D printing, which includes inkjet printing, fused deposition modeling, digital light processing, extrusion-based printing, microneedle array-based therapies, gene therapy, which includes microRNAs (miRNAs) therapy, and smart wound dressings for real time monitoring of wound conditions through assessment of pH, temperature, oxygen, moisture, metabolites, and their use for planning of better treatment strategies have been discussed in detail. The review further gives the future direction of treatments that will aid in lowering the healthcare burden caused due to chronic wounds.

Microneedles based on hyaluronic acid-polyvinyl alcohol with antibacterial, anti-inflammatory, and antioxidant effects promote diabetic wound healing

Diabetic wound healing has become one of the major clinical burdens due to uncontrolled bacterial growth and an increase in the risk of various microbial infections. Despite excellent antioxidant properties, the poor aqueous solubility of resveratrol (RES) hampers its applicability. In this study, we proposed a novel multifunctional microneedle patch loaded with RES-encapsulated polymeric micelles. Resveratrol micelles (RES MC) were loaded in the microneedle tip, while the base part was coated with the antibiotic gentamicin (GEN) to promote wound healing. The microneedle tip composed of sodium hyaluronate (HA) could effectively deliver the anti-inflammatory and antioxidant RES MC. Furthermore, the base of the microneedle patch composed of polyvinyl alcohol (PVA) offered excellent flexibility, releasing GEN and providing resistance to bacterial contamination, thereby further promoting wound repair. In vitro antibacterial experiments indicated that the bactericidal rate reached 99 %. Further, the wound healing rate was recorded as 86.05 % on the 11th day of diabetes wound treatment. Together, the multifunctional microneedle patch with excellent biocompatibility exhibited anti-inflammatory, antioxidant, and antibacterial effects on the wound healing process, potentiating its efficacy in the treatment of diabetic wounds.

Responsive porous microneedles with riboflavin ocular microinjection capability for facilitating corneal crosslinking

Riboflavin-5-phosphate (riboflavin) is the most commonly used photosensitizer in corneal crosslinking (CXL); while its efficient delivery into the stroma through the corneal epithelial barrier is challenging. In this paper, we presented novel responsive porous microneedles with ocular microinjection capability to deliver riboflavin controllably inside the cornea to facilitate CXL. The microneedle patch was composed of Poly (N-isopropyl acrylamide) (PNIPAM), graphene oxide (GO), and riboflavin-loaded gelatin. After penetrating the cornea by the stiff and porous gelatin needle tip, the photothermal-responsive characteristic of the PNIPAM/GO hydrogel middle layer could realize the contraction of the gel under the stimulation of near-infrared light, which subsequently could control the release of riboflavin from the backing layer into the cornea stromal site both in vitro and in vivo. Based on the microneedles system, we have demonstrated that this microinjection technique exhibited superior riboflavin delivery capacity and treatment efficacy to the conventional epithelial-on protocol in a rabbit keratoconus model, with benefits including minimal invasiveness and precise administering. Thus, we believe the responsive porous microneedles with riboflavin ocular microinjection capability are promising for clinical corneal crosslinking without epithelial debridement.

Cutting-edge microneedle innovations: Transforming the landscape of cardiovascular and metabolic disease management

Cardiovascular diseases (CVDs) and metabolic disorders (MDs) have surfaced as formidable challenges to global health, significantly imperiling human well-being. Recently, microneedles (MNs) have garnered substantial interest within the realms of CVD and MD research. Offering a departure from conventional diagnostic and therapeutic methodologies, MNs present a non-invasive, safe, and user-friendly modality for both monitoring and treatment, thereby marking substantial strides and attaining pivotal achievements in this avant-garde domain, while also unfurling promising avenues for future inquiry. This thorough review encapsulates the latest developments in employing MNs for both the surveillance and management of CVDs and MDs. Initially, it succinctly outlines the foundational principles and approaches of MNs in disease surveillance and therapy. Subsequently, it delves into the pioneering utilizations of MNs in the surveillance and management of CVDs and MDs. Ultimately, this discourse synthesizes and concludes the primary findings of this investigation, additionally prognosticating on the trajectory of MN technology.

Advances of Smart Stimulus-Responsive Microneedles in Cancer Treatment

Microneedles (MNs) have emerged as a highly promising technology for delivering drugs via the skin. They provide several benefits, including high drug bioavailability, non-invasiveness, painlessness, and high safety. Traditional strategies for intravenous delivery of anti-tumor drugs have risks of systemic toxicity and easy development of drug resistance, while MN technology facilitates precise delivery and on-demand release of drugs in local tissues. In addition, by further combining with stimulus-responsive materials, the construction of smart stimulus-responsive MNs can be achieved, which can respond to specific physical/chemical stimuli from the internal or external environment, thereby further improving the accuracy of tumor treatment and reducing toxicity to surrounding tissues/cells. This review systematically summarizes the classification, materials, and reaction mechanisms of stimulus-responsive MNs, outlines the benefits and challenges of various types of MNs, and details their application and latest progress in cancer treatment. Finally, the development prospects of smart MNs in tumor treatment are also discussed, bringing inspiration for future precision treatment of tumors.

Microneedle patch casting using a micromachined carbon master for enhanced drug delivery

For successful treatment of diseases, sufficient therapeutics must be provided to the body. Microneedle applications in therapeutic delivery and analytics sampling are restricted because of various issues, including smaller area for drug loading and analytics sampling. To achieve sufficient drug loading and analytics sampling and improve drug penetration while maintaining painless administration, patch-type microneedle arrays were designed and fabricated using polymer casting from a conical cavity mold. Microcavities were formed on a carbon plate via micromechanical machining. A porous polymer layer was coated on a microneedle patch (MNP). The pores of the porous polymer layer provided space and channels for drug delivery. A pH-sensitive polymer layer was employed to cap the porous polymer layer, which prevented drug leakage during storage and provided a stimulus drug release in response to body pH conditions. The drug can be delivered through holes connected to both sides of the patch. The drug release of the MNP was investigated in vitro and in vivo and showed conceptual proof that these MNs have the potential to enhance treatment protocols for various diseases with the flexibility of coating and therapeutic materials and offer significant scope for further variations and advancement.

Research Progress of Hydrogel Microneedles in Wound Management

Microneedles are a novel drug delivery system that offers advantages such as safety, painlessness, minimally invasive administration, simplicity of use, and controllable drug delivery. As a type of polymer microneedle with a three-dimensional network structure, hydrogel microneedles (HMNs) possess excellent biocompatibility and biodegradability and encapsulate various therapeutic drugs while maintaining drug activity, thus attracting significant attention. Recently, they have been widely employed to promote wound healing and have demonstrated favorable therapeutic effects. Although there are reviews about HMNs, few of them focus on wound management. Herein, we present a comprehensive overview of the design and preparation methods of HMNs, with a particular emphasis on their application status in wound healing, including acute wound healing, infected wound healing, diabetic wound healing, and scarless wound healing. Finally, we examine the advantages and limitations of HMNs in wound management and provide suggestions for future research directions.

Machine Learning Assists in the Design and Application of Microneedles

Microneedles (MNs), characterized by their micron-sized sharp tips, can painlessly penetrate the skin and have shown significant potential in disease treatment and biosensing. With the development of artificial intelligence (AI), the design and application of MNs have experienced substantial innovation aided by machine learning (ML). This review begins with a brief introduction to the concept of ML and its current stage of development. Subsequently, the design principles and fabrication methods of MNs are explored, demonstrating the critical role of ML in optimizing their design and preparation. Integration between ML and the applications of MNs in therapy and sensing were further discussed. Finally, we outline the challenges and prospects of machine learning-assisted MN technology, aiming to advance its practical application and development in the field of smart diagnosis and treatment.

Simulated skin model for in vitro evaluation of insertion performance of microneedles: design, development, and application verification

Microneedles, as a new efficient and safe transdermal drug delivery technology, has a wide range of applications in drug delivery, vaccination, medical cosmetology, and diagnostics. The degree of microneedles penetration into the skin determines the reliability of the delivery dose, but its evaluation is not yet well-established, which is one of the major constraints in the commercialization of microneedles. In this paper, a novel visual simulated skin model was developed with reference to the physical properties of real skin. The simulated skin model was well-designed and its prescription was optimized to make the thickness, hardness, elasticity, and other parameters close to those of real skin. It not only meets the need to assess the degree of insertion of microneedles but also provides a visual observation of the insertion state of microneedles.

Construct a Magnetic Pt/Ru Alloy Peroxidase Mimic As a Reusable and Cost-Effective "Signal-Off" Sensing Platform for Sensitive and Wide-Linear-Range Assay

"Signal-off" nanozyme sensing platforms are usually employed to detect analytes (e.g., ascorbic acid (AA) and alkaline phosphatase (ALP)), which are mostly based on oxidase (OXD) nanozymes. However, their drawbacks, like dissolved oxygen-dependent catalysis capability, relatively low enzyme activity, limited amount, and kind, may not favor sensing platforms' optimization. Meanwhile, with the need for sustainable development, a reusable "signal-off" sensing platform is essential for cutting down the cost of the assay, but it is rarely developed in previous studies. Magnetic peroxidase (POD) nanozymes potentially make up the deficiencies and become reusable and better "signal-off" sensing platforms. As a proof of concept, we first construct Fe3O4@polydopamine-supported Pt/Ru alloy nanoparticles (IOP@Pt/Ru) without stabilizers. IOP@Pt/Ru shows high POD activity with Vmax of 83.24 × 10-8 M·s-1 for 3,3',5,5'-Tetramethylbenzidine (TMB) oxidation. Meanwhile, its oxidation rate for TMB is slower than the reduction of oxidized TMB by reducers, favorable for a more significant detection signal. On the other hand, IOP@Pt/Ru possesses great magnet-responsive capability, making itself be recycled and reused for at least 15-round catalysis. When applying IOP@Pt/Ru for AA (ALP) detection, it performs better detectable adaptability, with a linear range of 0.01-0.2 mM (0.1-100 U/L) and a limit of detection of 0.01 mM (0.05 U/L), superior to most of OXD nanozyme-based ALP sensing platform. Finally, IOP@Pt/Ru's reusable assay was demonstrated in real blood samples for ALP assay, which has never been explored in previous studies. Overall, this study develops a reusable "signal-off" nanozyme sensing platform with superior assay capabilities than traditional OXD nanozymes, paves a new way to optimize nanozyme-based "signal-off" sensing platforms, and provides an idea for constructing inexpensive and sustainable sensing platforms.

Spatiotemporal fate of nanocarriers-embedded dissolving microneedles: the impact of needle dissolving rate

OBJECTIVE

Dissolving microneedles (DMNs) have shown great potential for transdermal drug delivery due to their excellent skin-penetrating ability and combination with nanocarriers (NCs) can realize targeted drug delivery. The objective of this study was to investigate the impact of microneedle dissolving rate on the in vivo fate of NC-loaded DMNs, which would facilitate the clinical translation of such systems.

METHODS

Solid lipid nanoparticles (SLNs) were selected as the model NC for loading in DMNs, which were labeled by P4 probes with aggregation-quenching properties. Sodium hyaluronate acid (HA) and chitosan (CS), with different aqueous dissolving rates, were chosen as model tip materials. The effects of needle dissolving rate on the in vivo fate of NC-loaded DMNs was investigated by tracking the distribution of fluorescence signals after transdermal exposure.

RESULTS

P4 SLNs achieved a deeper diffusion depth of 180 μm in DMN-HA with a faster dissolution rate, while the diffusion depth in DMN-CS with a slower dissolution rate was lower (140 μm). The in vivo experiments demonstrated that P4 SLNs had a T1/2 value of 12.14 h in DMN-HA, whilst a longer retention time was found in DMN-CS, with a T1/2 of 13.12 h.

CONCLUSIONS

This study confirmed that the in vivo diffusion rate of NC-loaded DMNs was determined by the dissolving rate of DMNs materials and provided valuable guidance for the design and development of NC-loaded DMNs in the future.

The Therapeutic Potential of Human Umbilical Cord Mesenchymal Stromal Cells Derived Exosomes for Wound Healing: Harnessing Exosomes as a Cell-free Therapy

Wound healing is a complicated process that involves many different types of cells and signaling pathways. Mesenchymal stromal cells (MSCs) have shown great potential as a treatment to improve wound healing because they can modulate inflammation, promote the growth of new blood vessels, and stimulate the regeneration of tissue. Recent evidence indicates MSCs-derived extracellular vesicles known as exosomes may mediate many of the therapeutic effects of MSCs on wound healing. Exosomes contain bioactive molecules such as proteins, lipids, and RNAs that can be transferred to recipient cells to modulate cellular responses. This article reviews current evidence on the mechanisms and therapeutic effects of human umbilical cord MSCs (hUCMSCs)-derived exosomes on wound healing. In vitro and animal studies demonstrate that hUCMSC-derived exosomes promote fibroblast proliferation/migration, angiogenesis, and re-epithelialization while reducing inflammation and scar formation. These effects are mediated by exosomal transfer of cytokines, growth factors, and regulatory microRNAs that modulate signaling pathways involved in wound healing. Challenges remain in exosome isolation methods, optimizing targeting/retention, and translation to human studies. Nevertheless, hUCMSCs-derived exosomes show promise as a novel cell-free therapeutic approach to accelerate wound closure and improve healing outcomes. Further research is warranted to fully characterize hUCMSCs-exosomal mechanisms and explore their clinical potential for wound management.

Biological scaffold as potential platforms for stem cells: Current development and applications in wound healing

Wound repair is a complex challenge for both clinical practitioners and researchers. Conventional approaches for wound repair have several limitations. Stem cell-based therapy has emerged as a novel strategy to address this issue, exhibiting significant potential for enhancing wound healing rates, improving wound quality, and promoting skin regeneration. However, the use of stem cells in skin regeneration presents several challenges. Recently, stem cells and biomaterials have been identified as crucial components of the wound-healing process. Combination therapy involving the development of biocompatible scaffolds, accompanying cells, multiple biological factors, and structures resembling the natural extracellular matrix (ECM) has gained considerable attention. Biological scaffolds encompass a range of biomaterials that serve as platforms for seeding stem cells, providing them with an environment conducive to growth, similar to that of the ECM. These scaffolds facilitate the delivery and application of stem cells for tissue regeneration and wound healing. This article provides a comprehensive review of the current developments and applications of biological scaffolds for stem cells in wound healing, emphasizing their capacity to facilitate stem cell adhesion, proliferation, differentiation, and paracrine functions. Additionally, we identify the pivotal characteristics of the scaffolds that contribute to enhanced cellular activity.

A Review of Recent Advances in Microneedle-Based Sensing within the Dermal ISF That Could Transform Medical Testing

Interstitial fluid (ISF) has attracted extensive attention in an extremely wide range of areas due to its unique advantages, such as portability, high precision, comfortable operation, and superior stability. In recent years, the microneedle (MN) technique has been considered to be an excellent tool for extracting ISF because it is painless and noninvasive. Recent reports have shown that MN has good application prospects in ISF extraction. In this review, we provide comprehensive and in-depth insight into integrated MN devices for ISF detection, covering the basic structure as well as the fabrication of integrated MN devices and various applications in ISF extraction. Challenges and prospects are highlighted, with a discussion on how to transition such MN-integrated devices toward personalized healthcare monitoring systems.

Recent advances in nanomaterial-driven strategies for diagnosis and therapy of vascular anomalies

Nanotechnology has demonstrated immense potential in various fields, especially in biomedical field. Among these domains, the development of nanotechnology for diagnosing and treating vascular anomalies has garnered significant attention. Vascular anomalies refer to structural and functional anomalies within the vascular system, which can result in conditions such as vascular malformations and tumors. These anomalies can significantly impact the quality of life of patients and pose significant health concerns. Nanoscale contrast agents have been developed for targeted imaging of blood vessels, enabling more precise identification and characterization of vascular anomalies. These contrast agents can be designed to bind specifically to abnormal blood vessels, providing healthcare professionals with a clearer view of the affected areas. More importantly, nanotechnology also offers promising solutions for targeted therapeutic interventions. Nanoparticles can be engineered to deliver drugs directly to the site of vascular anomalies, maximizing therapeutic effects while minimizing side effects on healthy tissues. Meanwhile, by incorporating functional components into nanoparticles, such as photosensitizers, nanotechnology enables innovative treatment modalities such as photothermal therapy and photodynamic therapy. This review focuses on the applications and potential of nanotechnology in the imaging and therapy of vascular anomalies, as well as discusses the present challenges and future directions.

Protein-based microneedles for biomedical applications: A systematic review

Microneedles are minimally-invasive devices with the unique capability of bypassing physiological barriers. Hence, they are widely used for different applications from drug/vaccine delivery to diagnosis and cosmetic fields. Recently, natural biopolymers (particularly carbohydrates and proteins) have garnered attention as safe and biocompatible materials with tailorable features for microneedle construction. Several review articles have dealt with carbohydrate-based microneedles. This review aims to highlight the less-noticed role of proteins through a systematic search strategy based on the PRISMA guideline from international databases of PubMed, Science Direct, Scopus, and Google Scholar. Original English articles with the keyword "microneedle(s)" in their titles along with at least one of the keywords "biopolymers, silk, gelatin, collagen, zein, keratin, fish-scale, mussel, and suckerin" were collected and those in which the proteins undertook a structural role were screened. Then, we focused on the structures and applications of protein-based microneedles. Also, the unique features of some protein biopolymers that make them ideal for microneedle construction (e.g., excellent mechanical strength, self-adhesion, and self-assembly), as well as the challenges associated with them were reviewed. Altogether, the proteins identified so far seem not only promising for the fabrication of "better" microneedles in the future but also inspiring for designing biomimetic structural biopolymers with ideal characteristics.

Exploration of the Delivery of Oncolytic Newcastle Disease Virus by Gelatin Methacryloyl Microneedles

Oncolytic Newcastle disease virus is a new type of cancer immunotherapy drug. This paper proposes a scheme for delivering oncolytic viruses using hydrogel microneedles. Gelatin methacryloyl (GelMA) was synthesized by chemical grafting, and GelMA microneedles encapsulating oncolytic Newcastle disease virus (NDV) were prepared by micro-molding and photocrosslinking. The release and expression of NDV were tested by immunofluorescence and hemagglutination experiments. The experiments proved that GelMA was successfully synthesized and had hydrogel characteristics. NDV was evenly dispersed in the allantoic fluid without agglomeration, showing a characteristic virus morphology. NDV particle size was 257.4 ± 1.4 nm, zeta potential was -13.8 ± 0.5 mV, virus titer TCID50 was 107.5/mL, and PFU was 2 × 107/mL, which had a selective killing effect on human liver cancer cells in a dose and time-dependent manner. The NDV@GelMA microneedles were arranged in an orderly cone array, with uniform height and complete needle shape. The distribution of virus-like particles was observed on the surface. GelMA microneedles could successfully penetrate 5% agarose gel and nude mouse skin. Optimal preparation conditions were freeze-drying. We successfully prepared GelMA hydrogel microneedles containing NDV, which could effectively encapsulate NDV but did not detect the release of NDV.

Design and fabrication of customizable microneedles enabled by 3D printing for biomedical applications

Microneedles (MNs) is an emerging technology that employs needles ranging from 10 to 1000 μm in height, as a minimally invasive technique for various procedures such as therapeutics, disease monitoring and diagnostics. The commonly used method of fabrication, micromolding, has the advantage of scalability, however, micromolding is unable to achieve rapid customizability in dimensions, geometries and architectures, which are the pivotal factors determining the functionality and efficacy of the MNs. 3D printing offers a promising alternative by enabling MN fabrication with high dimensional accuracy required for precise applications, leading to improved performance. Furthermore, enabled by its customizability and one-step process, there is propitious potential for growth for 3D-printed MNs especially in the field of personalized and on-demand medical devices. This review provides an overview of considerations for the key parameters in designing MNs, an introduction on the various 3D-printing techniques for fabricating this new generation of MNs, as well as highlighting the advancements in biomedical applications facilitated by 3D-printed MNs. Lastly, we offer some insights into the future prospects of 3D-printed MNs, specifically its progress towards translation and entry into market.

Swellable colorimetric microneedles for glucose detection based on glucose oxidase-like gold nanoparticles

BACKGROUND

Regular blood glucose monitoring is very important for diabetic patients. The composition of skin interstitial fluid (ISF) is similar to that of blood, which can be used for daily blood sugar detection and disease care. However, most methods of ISF extraction have complicated steps, may cause skin damage, and can only extract a limited amount of ISF, resulting in low detection efficiency. Therefore, it is very necessary to develop a detection method that can not only extract a large amount of ISF safely, efficiently, and conveniently, but also realize rapid detection of glucose level in ISF.

RESULTS

Here, we developed a gold nanoparticle (AuNP)-based swellable colorimetric MN patch with minimally invasive sampling function and real-time ISF glucose analysis ability. The MN patch could quickly absorb a large amount of skin ISF, and 60.2 mg of ISF was extracted within 10 min in vitro. It was divided into two layers: the tip layer was embedded with AuNPs with glucose oxidase (GOx)-like activity, which catalyzed the oxidation of glucose extracted from ISF and produced hydrogen peroxide (H2O2); horseradish peroxidase (HRP) encapsulated in the backing layer catalyzed the oxidation of 3, 3', 5, 5'-tetramethylbenzidine (TMB) by H2O2 to produce oxTMB, which led to a visible color shift in the backing layer. The ISF glucose level was judged by naked eyes and further quantified by color analysis with Image J software. As a result, the colorimetric MN patch successfully identified the normal blood sugar and hyperglycemia state in vivo.

SIGNIFICANCE

The colorimetric MN patch combined in-situ colorimetric sensing based on AuNP nanozyme with MN patch, which detected glucose level without blood drawing, increasing patients' compliance and reducing detection steps and time. Compared with the detection methods based on natural nanozymes, our method had better stability and sensitivity to complex environments (extreme pH and high temperature, etc.) in actual detection.

Novel microneedle platforms for the treatment of wounds by drug delivery: A review

The management and treatment of wounds are complex and pose a substantial financial burden to the patient. However, the complex environment of wounds leads to inadequate drug absorption to achieve the desired therapeutic effect. As a novel technological platform, microneedles are widely used in drug delivery because of their multiple drug loading, multistage drug release, and multiple designs of topology. This study systematically summarizes and analyzes the manufacturing methods and limitations of different microneedles, as well as the latest research advances in pain management, drug delivery, and healing promotion, and presents the challenges and opportunities for clinical applications. On this basis, the development of microneedles in external wound repair and management is envisioned, and it is hoped that this study can provide guidelines for the design of microneedle systems in different application contexts, including the selection of materials, preparation methods, and structural design, to achieve better healing and regeneration results.

Advancement in Biosensor Technologies of 2D MaterialIntegrated with Cellulose-Physical Properties

This review paper provides an in-depth analysis of recent advancements in integrating two-dimensional (2D) materials with cellulose to enhance biosensing technology. The incorporation of 2D materials such as graphene and transition metal dichalcogenides, along with nanocellulose, improves the sensitivity, stability, and flexibility of biosensors. Practical applications of these advanced biosensors are explored in fields like medical diagnostics and environmental monitoring. This innovative approach is driving research opportunities and expanding the possibilities for diverse applications in this rapidly evolving field.

Multifunctional Microneedle Patches via Direct Ink Drawing of Nanocomposite Inks for Personalized Transdermal Drug Delivery

Additive manufacturing, commonly known as 3D printing, allows decentralized drug fabrication of orally administered tablets. Microneedles are comparatively favorable for self-administered transdermal drug delivery with improved absorption and bioavailability. Due to the cross-scale geometric characteristics, 3D-printed microneedles face a significant trade-off between the feature resolution and production speed in conventional layer-wise deposition sequences. In this study, we introduce an economical and scalable direct ink drawing strategy to create drug-loaded microneedles. A freestanding microneedle is efficiently generated upon each pneumatic extrusion and controlled drawing process. Sharp tips of ∼5 μm are formed with submillimeter nozzles, representing 2 orders of magnitude improved resolution. As the key enabler of this fabrication strategy, the yield-stress fluid inks are formulated by simply filling silica nanoparticles into regular polymer solutions. The approach is compatible with various microneedles based on dissolvable, biodegradable, and nondegradable polymers. Various matrices are readily adopted to adjust the release behaviors of the drug-loaded microneedles. Successful fabrication of multifunctional patches with heterogeneously integrated microneedles allows the treatment of melanoma via synergistic photothermal therapy and combination chemotherapy. The personalized patches are designed for cancer severity to achieve high therapeutic efficacy with minimal side effects. The direct ink drawing reported here provides a facile and low-cost fabrication strategy for multifunctional microneedle patches for self-administering transdermal drug delivery.

Modern microelectronics and microfluidics on microneedles

Possessing the attractive advantages of moderate invasiveness and high compliance, there is no doubt that microneedles (MNs) have been a gradually rising star in the field of medicine. Recent evidence implies that microelectronics technology based on microcircuits, microelectrodes and other microelectronic elements combined with MNs can realize mild electrical stimulation, drug release and various types of electrical sensing detection. In addition, the combination of microfluidics technology and MNs makes it possible to transport fluid drugs and access a small quantity of body fluids which have shown significant untapped potential for a wide range of diagnostics. Of particular note is that combining both technologies and MNs is more difficult, but is promising to build a modern healthcare platform with more comprehensive functions. This review introduces the properties of MNs that can form integrated systems with microelectronics and microfluidics, and summarizes these systems and their applications. Furthermore, the future challenges and perspectives of the integrated systems are conclusively proposed.

Going below and beyond the surface: Microneedle structure, materials, drugs, fabrication, and applications for wound healing and tissue regeneration

Microneedle, as a novel drug delivery system, has attracted widespread attention due to its non-invasiveness, painless and simple administration, controllable drug delivery, and diverse cargo loading capacity. Although microneedles are initially designed to penetrate stratum corneum of skin for transdermal drug delivery, they, recently, have been used to promote wound healing and regeneration of diverse tissues and organs and the results are promising. Despite there are reviews about microneedles, few of them focus on wound healing and tissue regeneration. Here, we review the recent advances of microneedles in this field. We first give an overview of microneedle system in terms of its potential cargos (e.g., small molecules, macromolecules, nucleic acids, nanoparticles, extracellular vesicle, cells), structural designs (e.g., multidrug structures, adhesive structures), material selection, and drug release mechanisms. Then we briefly summarize different microneedle fabrication methods, including their advantages and limitations. We finally summarize the recent progress of microneedle-assisted wound healing and tissue regeneration (e.g., skin, cardiac, bone, tendon, ocular, vascular, oral, hair, spinal cord, and uterine tissues). We expect that our article would serve as a guideline for readers to design their microneedle systems according to different applications, including material selection, drug selection, and structure design, for achieving better healing and regeneration efficacy.

Development of fast dissolving polymer-based microneedles for delivery of an antigenic melanoma cell membrane

Delivery of cancer cell membranes (CM) is a new approach for the activation of the immune system and the induction of immunotherapy of cancer. Local delivery of melanoma CM into skin can induce efficient immune stimulation of antigen presenting cells (APCs), such as dendritic cells. In the current study, fast dissolving microneedles (MNs) were developed for the delivery of melanoma B16F10 CM. Two polymers were tested for the fabrication of MNs: poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) and hyaluronic acid (HA). The incorporation of CM in MNs was achieved through coating of the MNs using a multi-step layering procedure or the micromolding technique. The CM loading and its stabilization were improved by adding sugars (sucrose and trehalose) and a surfactant (Poloxamer 188), respectively. In an ex vivo experiment, both PMVE-MA and HA showed fast dissolutions (<30 s) after insertion into porcine skin. However, HA-MN showed better mechanical properties, namely improved resistance to fracture when submitted to a compression force. Overall, a B16F10 melanoma CM-dissolving MN system was efficiently developed as a promising device suggesting further studies in immunotherapy and melanoma applications.

Recent advancements in the expedition of microneedles: from lab worktops to diagnostic care centers

Microneedle (MN) technology plays a significant role in bioengineering as it allows for minimally invasive exposure to the skin via the non-invasive procedure, increased drug permeability, and improved biological molecule detectability in the epidermal layers, all while improving therapeutic safety and effectiveness. However, MNs have several significant drawbacks, including difficulty scaling up, variability in drug delivery pattern regarding the skin's external environment, blockage of dermal tissues, induction of inflammatory response at the administration site, and limitation of dosing based on the molecular weight of drug and size. Despite these drawbacks, MNs have emerged as a special transdermal theranostics instrument in clinical research to assess physiological parameters. Bioimaging technology relies on microneedles that can measure particular analytes in the extracellular fluid effectively by crossing the stratum corneum, making them "a unique tool in diagnostics detection and therapeutic application inside the body." This review article discusses the recent advances in the applications especially related to the diagnostics and toxicity challenges of microneedles. In addition, this review article discusses the clinical state and commercial accessibility of microneedle technology-based devices in order to provide new information to scientists and researchers.

Exosome-loaded microneedle patches: Promising factor delivery route

During the past decades, the advent of different microneedle patch (MNPs) systems paves the way for the targeted and efficient delivery of several growth factors into the injured sites. MNPs consist of several micro-sized (25-1500 μm) needle rows for painless delivery of incorporated therapeutics and increase of regenerative outcomes. Recent data have indicated the multifunctional potential of varied MNP types for clinical applications. Advances in the application of materials and fabrication processes enable researchers and clinicians to apply several MNP types for different purposes such as inflammatory conditions, ischemic disease, metabolic disorders, vaccination, etc. Exosomes (Exos) are one of the most interesting biological bioshuttles that participate in cell-to-cell paracrine interaction with the transfer of signaling biomolecules. These nano-sized particles, ranging from 50 to 150 nm, can exploit several mechanisms to enter the target cells and deliver their cargo into the cytosol. In recent years, both intact and engineered Exos have been increasingly used to accelerate the healing process and restore the function of injured organs. Considering the numerous benefits provided by MNPs, it is logical to hypothesize that the development of MNPs loaded with Exos provides an efficient therapeutic platform for the alleviation of several pathologies. In this review article, the authors collected recent advances in the application of MNP-loaded Exos for therapeutic purposes.

The use of cellulose, chitosan and hyaluronic acid in transdermal therapeutic management of obesity: A review

Obesity is a clinical condition with rising popularity and detrimental impacts on human health. According to the World Health Organization, obesity is the sixth most common cause of death worldwide. It is challenging to combat obesity because medications that are successful in the clinical investigation have harmful side effects when administered orally. The conventional approaches for treating obesity primarily entail synthetic compounds and surgical techniques but possess severe adverse effects and recurrences. As a result, a safe and effective strategy to combat obesity must be initiated. Recent studies have shown that biological macromolecules of the carbohydrate class, such as cellulose, hyaluronic acid, and chitosan, can enhance the release and efficacy of medications for obesity but due to their short biological half-lives and poor oral bioavailability, their distribution rate is affected. This helps to comprehend the need for an effective therapeutic approach via a transdermal drug delivery system. This review focuses on the transdermal administration, utilizing cellulose, chitosan, and hyaluronic acid via microneedles, as it offers a promising solution to overcome existing therapy limitations in managing obesity and it also highlights how microneedles can effectively deliver therapeutic substances through the skin's outer layer, bypassing pain receptors and specifically targeting adipose tissue.

Flexible Monitoring, Diagnosis, and Therapy by Microneedles with Versatile Materials and Devices toward Multifunction Scope

Microneedles (MNs) have drawn rising attention owing to their merits of convenience, noninvasiveness, flexible applicability, painless microchannels with boosted metabolism, and precisely tailored multifunction control. MNs can be modified to serve as novel transdermal drug delivery, which conventionally confront with the penetration barrier caused by skin stratum corneum. The micrometer-sized needles create channels through stratum corneum, enabling efficient drug delivery to the dermis for gratifying efficacy. Then, incorporating photosensitizer or photothermal agents into MNs can conduct photodynamic or photothermal therapy, respectively. Besides, health monitoring and medical detection by MN sensors can extract information from skin interstitial fluid and other biochemical/electronic signals. Here, this review discloses a novel monitoring, diagnostic, and therapeutic pattern by MNs, with elaborate discussion about the classified formation of MNs together with various applications and inherent mechanism. Hereby, multifunction development and outlook from biomedical/nanotechnology/photoelectric/devices/informatics to multidisciplinary applications are provided. Programmable intelligent MNs enable logic encoding of diverse monitoring and treatment pathways to extract signals, optimize the therapy efficacy, real-time monitoring, remote control, and drug screening, and take instant treatment.

Tailoring micro/nano-fibers for biomedical applications

Nano/micro fibers have evoked much attention of scientists and have been researched as cutting edge and hotspot in the area of fiber science in recent years due to the rapid development of various advanced manufacturing technologies, and the appearance of fascinating and special functions and properties, such as the enhanced mechanical strength, high surface area to volume ratio and special functionalities shown in the surface, triggered by the nano or micro-scale dimensions. In addition, these outstanding and special characteristics of the nano/micro fibers impart fiber-based materials with wide applications, such as environmental engineering, electronic and biomedical fields. This review mainly focuses on the recent development in the various nano/micro fibers fabrication strategies and corresponding applications in the biomedical fields, including tissue engineering scaffolds, drug delivery, wound healing, and biosensors. Moreover, the challenges for the fabrications and applications and future perspectives are presented.

Globefish-Inspired Balloon Catheter with Intelligent Microneedle Coating for Endovascular Drug Delivery

Balloon catheters exhibit important values in treating cardiovascular diseases, while their functions are still under improvements. Here, inspired by the thorn-hiding and deflating-inflating characteristics of globefish, intelligent balloon catheters decorated with invisible microneedles are presented for endovascular drug delivery to inhibit postintervention restenosis (PIRS). These microneedle balloon catheters (MNBCs) fabricated by dipping and rolling-assisted template replication contain three coating layers of sandwiched drug-carrying microneedles and black phosphorus (BP)-carrying gelatin. During the emplacement, the microneedles of MNBCs are hidden under the outermost gelatin protective layer, allowing smooth movements inside the blood vessel. After reaching the destination, the embedded BP converts near infrared (NIR) into heat, increases local temperature, and melts the gelatin layer, enabling the exposure and vascular penetration of the microneedles. Besides, as the innermost gelatin also melts, the microneedles can detach from the balloon catheter and be left inside the blood vessel for continuous drug release. Based on advantages of responsiveness, penetration capacity, and biosafety, it is demonstrated that the MNBCs behave satisfactorily in delivering rapamycin to inhibit abdominal aorta restenosis in rats. All these features indicate that these MNBCs are promising medical devices for clinical applications.

Polymeric microneedles for enhanced drug delivery in cancer therapy

Microneedles (MNs) have attracted the interest of researchers. Polymeric MNs offer tremendous promise as drug delivery vehicles for bio-applications because of their high loading capacity, strong patient adherence, excellent biodegradability and biocompatibility, low toxicity, and extremely cheap cost. Incorporating enhanced-property nanomaterials into polymeric MNs matrix increases their features such as better mechanical strength, sustained drug delivery, lower toxicity, and higher therapeutic effects, therefore considerably increasing their biomedical application. This paper discusses polymeric MN fabrication techniques and the present status of polymeric MNs as a delivery method for enhanced drug delivery in cancer therapeutic applications. Furthermore, the opportunities and challenges of polymeric MNs for improved drug delivery in cancer therapy are highlighted.

Christmas Tree-Shaped Microneedles as FOLFIRINOX Spatiotemporal Delivery System for Pancreatic Cancer Treatment

As an effective combination chemotherapy, FOLFIRINOX regimen (fluorouracil, leucovorin, irinotecan, and oxaliplatin) has shown definite antitumor efficacy for treating pancreatic cancer (PC) nowadays. However, the traditional systematic administration of these chemotherapeutics limits the drug targeting and causes unwanted effects. Herein, we present a novel Christmas tree-shaped adhesive microneedle (MN) patch coloading fluorouracil, leucovorin, irinotecan, and oxaliplatin simultaneously to realize spatiotemporal FOLFIRINOX therapy in situ. Such MN patch was fabricated by using a layer-by-layer mold replication method, in which oxaliplatin and leucovorin are encapsulated in the top MNs, while irinotecan and fluorouracil are encapsulated in the bottom MNs. The multilayer structure imparts the MNs with enhanced adhesive ability and spatiotemporal drug release property, contributing to the antitumor effect on PC organoid models. Therefore, our Christmas tree-shaped MN patch represents an innovative approach for spatiotemporal multiple-drug delivering and realizes the combination chemotherapy for PC in a single platform.

Microneedles-based drug delivery strategies: A breakthrough approach for the management of pain

Pain is a personalized event or body alarm system that can limit a patient's activities and lead to negative repercussions. The commercially available conventional treatment strategies like oral, parenteral, and topical drug delivery systems for pain management are associated with side effects and poor patient compliance. The transdermal route is eminent for its painless distribution. Among transdermal drug delivery system, microneedles (MNs) are gaining attention for their application with delivery at the deeper dermal layer because it bypasses the major barrier of the skin, easily accesses the skin dermal microcirculation, prevents damage to dermal blood vessels, and can be simply inserted into the skin without utilizing any additional applicator devices. Hence, considered a promising drug delivery strategy with high patient compliance. This review highlights the recent advancements of MNs in pain management. The present work mainly emphasizes all the case studies reported from the past 10 years that utilize MNs containing therapeutics in the treatment of chronic pain-associated diseases like rheumatoid arthritis, neuropathic pain, osteoarthritis, psoriatic arthritis, and atopic dermatitis. These studies have proven the efficacious application of MNs in the management of chronic pain and inflammation. The review also covered the clinical trials, patents, and future goals of pain management by using MNs.