Enzyme-mediated fabrication of nanocomposite hydrogel microneedles for tunable mechanical strength and controllable transdermal efficiency

Transdermal delivery of timolol maleate using hydrogel microneedles for the treatment of infantile haemangiomas

Infantile haemangioma (IH), the most prevalent vascular tumour in infants, requires early intervention because of the potential complications in critical areas such as the head and face. Current treatments, including topical timolol maleate (TIM), face challenges such as poor compliance, low drug utilisation, and lengthy treatment durations. In this study, we developed a hydrogel microneedle (MN) using photocurable bovine serum albumin methacryloyl (BSAMA) as a carrier for TIM. Our results showed the controlled release of TIM from BSAMA-TIM MNs, with approximately 69 % release ratio within 72 h. In-vivo studies on nude mice demonstrated that BSAMA-TIM-MNs inhibited the growth of haemangioma xenografts. Our TIM-delivering MNs exhibited high therapeutic efficacy, minimal cytotoxicity, and reduced dosing frequency. In conclusion, BSAMA-TIM MNs provide a promising strategy for treating IH.

Dissolving microneedles in transdermal drug delivery: A critical analysis of limitations and translation challenges

Microneedles (MNs) have emerged as an innovative approach for transdermal drug delivery, offering an efficient and minimally invasive alternative to conventional injections and oral delivery systems. While their potential has been widely recognized and extensively studied, the translation of MN technology into clinical practice remains limited. Despite the vast amount of published research, much of it involves over-complexification without addressing the core barriers to practical application. For example, dissolving/degradable MNs face key limitations such as poor drug loading capacity, low dosing consistency, and challenges in delivering effective therapeutic concentrations. These constraints restrict their utility to niche applications, such as vaccination or delivering potent drugs that require minimal doses. Additionally, the lack of standardized quality control measures, the complex manufacturing processes, and the high costs associated specifically with sterile/aseptic production further impede clinical translation. Regulatory frameworks for MNs remain vague, slowing the development of products that meet approval standards. This review critically examines the fundamental barriers to dissolving/degradable MN commercialization, as the most studied type of MN, while exploring promising strategies to overcome them. Advances in formulation science, fabrication techniques, and material engineering have demonstrated potential in enhancing drug loading efficiency and delivery consistency. Moreover, the establishment of clearer regulatory guidelines and scalable production strategies could significantly accelerate the commercialization of MN technology. By shifting focus toward pragmatic and clinically relevant solutions, this review aims to bridge the gap between research innovations and real-world applications, paving the way for broader implementation of MN technology in medicine.

Enzyme-mediated hydrogelation for biomedical applications: A review

Hydrogels possess significant potential for biomedical applications due to their flexibility and biocompatibility. However, current physical or chemical methods for their preparation often fail to balance biocompatibility and mechanical properties, limiting their application scope. Enzymatic preparation of hydrogels offers advantages including mild reaction conditions, absence of toxic substances, and superior biocompatibility. This review focuses on the enzymatic preparation systems of hydrogels and its application in the fast-growing biomedical field. Firstly, the mechanisms of enzyme-mediated hydrogel preparation can be categorized into four classes: enzyme cross-linking, enzyme polymerization, enzyme-mediated self-assembly of small molecular gelators, and enzyme-induced pH changes. Hydrogels prepared through the first two mechanisms retain the mechanical advantages of chemically cross-linked hydrogels while preserving the inherent biocompatibility. Additionally, hydrogels prepared via the latter two mechanisms exhibit rapid responses to external stimuli similar to physically crosslinked hydrogels while maintaining high biocompatibility. Furthermore, we discuss their application in biomedical scope and analyze the correlation between the mechanism of enzyme-mediated hydrogels and their respective application domains. Finally, the current challenges faced by enzymatically mediated hydrogelation are summarized; notably that enzymes incorporated and immobilized during hydrogel preparation remain active, resulting in catalytic activity exhibited by these enzymatically mediated hydrogels, which broadens their potential applications.

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.

Microneedle-based nanodrugs for tumor immunotherapy

Microneedles have emerged as a promising and effective method for delivering therapeutic drugs and immunobiologics to treat various diseases. It is widely recognized that immune therapy has limited efficacy in solid tumors due to physical barriers and the immunosuppressive tumor microenvironment. Microneedle-based nanodrugs (NDMNs) offer a novel approach to overcome these limitations. These tiny needles are designed to load a variety of inorganic and organic nanoparticles, antigen vaccines, gene drugs, oncolytic viruses, and more. Utilizing microneedle arrays, NDMNs can effectively penetrate the skin barrier, delivering drugs precisely to the tumor site or immunoactive regions within the skin. Additionally, by designing and optimizing the microneedle structure, shape, and functionality, NDMNs enable precise drug release and efficient penetration, thereby enhancing the efficacy of tumor immunotherapy. In this review, we comprehensively discuss the pivotal role of NDMNs in cancer immunotherapy, summarizing innovative microneedle design strategies, mechanisms of immune activation, and delivery strategies of various nanodrugs. Furthermore, we explore the current clinical realities, limitations, and future prospects of NDMNs in tumor immunotherapy.

Multifunctional Hydrogel Microneedles (HMNs) in Drug Delivery and Diagnostics

Hydrogel microneedles (HMNs) have emerged as a transformative platform for minimally invasive drug delivery and biosensing, offering enhanced bioavailability, controlled drug release, and real-time biomarker detection. By leveraging swelling hydrogels, nanomaterial integration, and stimuli-responsive properties, HMNs provide precision medicine capabilities across diverse therapeutic and diagnostic applications. However, challenges remain in mechanical stability, as hydrogel-based MNs must balance flexibility with sufficient strength for skin penetration. Drug retention and controlled release require optimization to prevent premature diffusion and ensure sustained therapeutic effects. Additionally, biosensing accuracy is influenced by variability in interstitial fluid extraction and signal transduction. Clinical translation is hindered by regulatory hurdles, scalability concerns, and the need for extensive safety validation in human trials. This review critically examines the key materials, fabrication techniques, functional properties, and testing frameworks of HMNs while addressing these limitations. Furthermore, we explore future research directions in smart wearable MNs, AI-assisted biosensing, and hybrid drug-device platforms to optimize transdermal medicine. Overcoming these barriers will drive the clinical adoption of HMNs, paving the way for next-generation patient-centered therapeutics and diagnostics.

Design of nanosystems for melanoma treatment

Melanoma is a prevalent and concerning form of skin cancer affecting millions of individuals worldwide. Unfortunately, traditional treatments can be invasive and painful, prompting the need for alternative therapies with improved efficacy and patient outcomes. Nanosystems offer a promising solution to these obstacles through the rational design of nanoparticles (NPs) which are structured into nanocomposite forms, offering efficient approaches to cancer treatment procedures. A range of NPs consisting of polymeric, metallic and metal oxide, carbon-based, and virus-like NPs have been studied for their potential in treating skin cancer. This review summarizes the latest developments in functional nanosystems aimed at enhancing melanoma treatment. The fundamentals of these nanosystems, including NPs and the creation of various functional nanosystem types, facilitating melanoma treatment are introduced. Then, the advances in the applications of functional nanosystems for melanoma treatment are summarized, outlining both their benefits and the challenges encountered in implementing nanosystem therapies.

Biomaterials for non-invasive trans-tympanic drug delivery: requirements, recent advances and perspectives

Various non-invasive delivery systems have recently been developed as an alternative to conventional injections. Local transdermal administration represents the most attractive method due to the low systemic side effects, excellent ease of administration, and persistent drug release. The tympanic membrane (TM), a major barrier between the outer and middle ear, has a similar structure of the stratum corneum compared to the surface of the skin. After several attempts, non-invasive trans-tympanic drug delivery has been regarded as a promising option in the treatment of middle and inner ear diseases. The round window membrane (RWM) was a possible non-invasive delivery approach from the middle to inner ear. The improved permeability of nanocarriers crossing the RWM is a current hotspot in therapeutics for inner ear diseases. In this review, we include the latest studies exploring non-invasive trans-tympanic delivery to treat middle and inner ear diseases. Both passive and active delivery systems are described. A summary of the benefits and disadvantages of various delivery systems in clinical practice and production procedures is introduced. Finally, future possible approaches for its effective application as a non-invasive middle and inner ear drug delivery system are characterised.

Progress in Topical and Transdermal Drug Delivery Research-Focus on Nanoformulations

Skin is the largest organ and a multifunctional interface between the body and its environment. It acts as a barrier against cold, heat, injuries, infections, chemicals, radiations or other exogeneous factors, and it is also known as the mirror of the soul. The skin is involved in body temperature regulation by the storage of fat and water. It is an interesting tissue in regard to the local and transdermal application of active ingredients for prevention or treatment of pathological conditions. Topical and transdermal delivery is an emerging route of drug and cosmetic administration. It is beneficial for avoiding side effects and rapid metabolism. Many pharmaceutical, technological and cosmetic innovations have been described and patented recently in the field. In this review, the main features of skin morphology and physiology are presented and are being followed by the description of classical and novel nanoparticulate dermal and transdermal drug formulations. The biophysical aspects of the penetration of drugs and cosmetics into or across the dermal barrier and their investigation in diffusion chambers, skin-on-a-chip devices, high-throughput measuring systems or with advanced analytical techniques are also shown. The current knowledge about mathematical modeling of skin penetration and the future perspectives are briefly discussed in the end, all also involving nanoparticulated systems.

Application of hydrogel microneedles in the oral cavity

Microneedles are a transdermal drug delivery system in which the needle punctures the epithelium to deliver the drug directly to deep tissues, thus avoiding the influence of the first-pass effect of the gastrointestinal tract and minimizing the likelihood of pain induction. Hydrogel microneedles are microneedles prepared from hydrogels that have good biocompatibility, controllable mechanical properties, and controllable drug release and can be modified to achieve environmental control of drug release in vivo. The large epithelial tissue in the oral cavity is an ideal site for drug delivery via microneedles. Hydrogel microneedles can overcome mucosal hindrances to delivering drugs to deep tissues; this prevents humidity and a highly dynamic environment in the oral cavity from influencing the efficacy of the drugs and enables them to obtain better therapeutic effects. This article analyzes the materials and advantages of common hydrogel microneedles and reviews the application of hydrogel microneedles in the oral cavity.