Enhanced Cancer Vaccination by In Situ Nanomicelle-Generating Dissolving Microneedles

Diagnostic, Therapeutic, and Theranostic Multifunctional Microneedles

Microneedles (MNs) have maintained their popularity in therapeutic and diagnostic medical applications throughout the past decade. MNs are originally designed to gently puncture the stratum corneum layer of the skin and have lately evolved into intelligent devices with functions including bodily fluid extraction, biosensing, and drug administration. MNs offer limited invasiveness, ease of application, and minimal discomfort. Initially manufactured solely from metals, MNs are now available in polymer-based varieties. MNs can be used to create systems that deliver drugs and chemicals uniformly, collect bodily fluids, and are stimulus-sensitive. Although these advancements are favorable in terms of biocompatibility and production costs, they are insufficient for the therapeutic use of MNs. This is the first comprehensive review that discusses individual MN functions toward the evolution and development of smart and multifunctional MNs for a variety of novel and impactful future applications. The study examines fabrication techniques, application purposes, and experimental details of MN constructs that perform multiple functions concurrently, including sensing, drug-molecule release, sampling, and remote communication capabilities. It is highly likely that in the near future, MN-based smart devices will be a useful and important component of standard medical practice for different applications.

Unravelling the role of microneedles in drug delivery: Principle, perspectives, and practices

In recent year, the research of transdermal drug delivery systems has got substantial attention towards the development of microneedles (MNs). This shift has occurred due to multifaceted advantages of MNs as they can be utilized to deliver the drug deeper to the skin with minimal invasion, offer successful delivery of drugs and biomolecules that are susceptible to degradation in gastrointestinal tract (GIT), act as biosensors, and help in monitoring the level of biomarkers in the body. These can be fabricated into different types based on their applications as well as material for fabrication. Some of their types include solid MNs, hollow MNs, coated MNs, hydrogel forming MNs, and dissolving MNs. These MNs deliver the therapeutics via microchannels deeper into the skin. The coated and hollow MNs have been found successful. However, they suffer from poor drug loading and blocking of pores. In contrast, dissolving MNs offer high drug loading. These MNs have also been utilized to deliver vaccines and biologicals. They have also been used in cosmetics. The current review covers the different types of MNs, materials used in their fabrication, properties of MNs, and various case studies related to their role in delivering therapeutics, monitoring level of biomarkers/hormones in body such as insulin. Various patents and clinical trials related to MNs are also covered. Covered are the major bottlenecks associated with their clinical translation and potential future perspectives.

Advancing immunotherapy using biomaterials to control tissue, cellular, and molecular level immune signaling in skin

Immunotherapies have been transformative in many areas, including cancer treatments, allergies, and autoimmune diseases. However, significant challenges persist in extending the reach of these technologies to new indications and patients. Some of the major hurdles include narrow applicability to patient groups, transient efficacy, high cost burdens, poor immunogenicity, and side effects or off-target toxicity that results from lack of disease-specificity and inefficient delivery. Thus, there is a significant need for strategies that control immune responses generated by immunotherapies while targeting infection, cancer, allergy, and autoimmunity. Being the outermost barrier of the body and the first line of host defense, the skin presents a unique immunological interface to achieve these goals. The skin contains a high concentration of specialized immune cells, such as antigen-presenting cells and tissue-resident memory T cells. These cells feature diverse and potent combinations of immune receptors, providing access to cellular and molecular level control to modulate immune responses. Thus, skin provides accessible tissue, cellular, and molecular level controls that can be harnessed to improve immunotherapies. Biomaterial platforms - microneedles, nano- and micro-particles, scaffolds, and other technologies - are uniquely capable of modulating the specialized immunological niche in skin by targeting these distinct biological levels of control. This review highlights recent pre-clinical and clinical advances in biomaterial-based approaches to target and modulate immune signaling in the skin at the tissue, cellular, and molecular levels for immunotherapeutic applications. We begin by discussing skin cytoarchitecture and resident immune cells to establish the biological rationale for skin-targeting immunotherapies. This is followed by a critical presentation of biomaterial-based pre-clinical and clinical studies aimed at controlling the immune response in the skin for immunotherapy and therapeutic vaccine applications in cancer, allergy, and autoimmunity.

Applications and prospects of microneedles in tumor drug delivery

As drug delivery devices, microneedles are used widely in the local administration of various drugs. Such drug-loaded microneedles are minimally invasive, almost painless, and have high drug delivery efficiency. In recent decades, with advancements in microneedle technology, an increasing number of adaptive, engineered, and intelligent microneedles have been designed to meet increasing clinical needs. This article summarizes the types, preparation materials, and preparation methods of microneedles, as well as the latest research progress in the application of microneedles in tumor drug delivery. This article also discusses the current challenges and improvement strategies in the use of microneedles for tumor drug delivery.

Design and Evaluation of Synthetic Delivery Formulations for Peptide-Based Cancer Vaccines

With the recent advances in neoantigen identification, peptide-based cancer vaccines offer substantial potential in the field of immunotherapy. However, rapid clearance, low immunogenicity, and insufficient antigen-presenting cell (APC) uptake limit the efficacy of peptide-based cancer vaccines. This review explores the barriers hindering vaccine efficiency, highlights recent advancements in synthetic delivery systems, and features strategies for the key delivery steps of lymph node (LN) drainage, APC delivery, cross-presentation strategies, and adjuvant incorporation. This paper also discusses the design of preclinical studies evaluating vaccine efficiency, including vaccine administration routes and murine tumor models.

Advances in biomedical systems based on microneedles: design, fabrication, and application

Wearable devices have become prevalent in biomedical studies due to their convenient portability and potential utility in biomarker monitoring for healthcare. Accessing interstitial fluid (ISF) across the skin barrier, microneedle (MN) is a promising minimally invasive wearable technology for transdermal sensing and drug delivery. MN has the potential to overcome the limitations of conventional transdermal drug administration, making it another prospective mode of drug delivery after oral and injectable. Subsequently, combining MN with multiple sensing approaches has led to its extensive application to detect biomarkers in ISF. In this context, employing MN platforms and control schemes to merge diagnostic and therapeutic capabilities into theranostic systems will facilitate on-demand therapy and point-of-care diagnostics, paving the way for future MN technologies. A comprehensive analysis of the growing advances of microneedles in biomedical systems is presented in this review to summarize the latest studies for academics in the field and to offer for reference the issues that need to be addressed in MN application for healthcare. Covering an array of novel studies, we discuss the following main topics: classification of microneedles in the biomedical field, considerations of MN design, current applications of microneedles in diagnosis and therapy, and the regulatory landscape and prospects of microneedles for biomedical applications. This review sheds light on the significance of microneedle-based innovations, presenting an analysis of their potential implications and contributions to the community of wearable healthcare technologies. The review provides a comprehensive understanding of the field's current state and potential, making it a valuable resource for academics and clinicians seeking to harness the full potential of MN applications.

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.

Tiny titans- unravelling the potential of polysaccharides and proteins based dissolving microneedles in drug delivery and theranostics: A comprehensive review

In recent years, microneedles (MNs) have emerged as a promising alternative to traditional drug delivery systems in transdermal drug delivery. The use of MNs has demonstrated significant potential in improving patient acceptance and convenience while avoiding the invasiveness of traditional injections. Dissolving, solid, hollow, coated, and hydrogel microneedles are among the various types studied for drug delivery. Dissolving microneedles (DMNs), in particular, have gained attention for their safety, painlessness, patient convenience, and high delivery efficiency. This comprehensive review primarily focuses on different types of microneedles, fabrication methods, and materials used in fabrication of DMNs such as hyaluronic acid, chitosan, alginate, gelatin, collagen, silk fibroin, albumin, cellulose and starch, to list a few. The review also provides an exhaustive discussion on the applications of DMNs, including the delivery of vaccines, cosmetic agents, contraceptives, hormone and genes, and other therapeutic applications like for treating cancer, skin diseases, and diabetes, among others, are covered in this review. Additionally, this review highlights some of the DMN systems that are presently undergoing clinical trials. Finally, the review discusses current advances and trends in DMNs, as well as future prospective directions for this ground-breaking technology in drug delivery.

Biomaterial-Based Sustained-Release Drug Formulations for Localized Cancer Immunotherapy

Cancer immunotherapy has revolutionized clinical cancer treatments by taking advantage of the immune system to selectively and effectively target and kill cancer cells. However, clinical cancer immunotherapy treatments often have limited efficacy and/or present severe adverse effects associated primarily with their systemic administration. Localized immunotherapy has emerged to overcome these limitations by directly targeting accessible tumors via local administration, reducing potential systemic drug distribution that hampers drug efficacy and safety. Sustained-release formulations can prolong drug activity at target sites, which maximizes the benefits of localized immunotherapy to increase the therapeutic window using smaller dosages than those used for systemic injection, avoiding complications of frequent dosing. The performance of sustained-release formulations for localized cancer immunotherapy has been validated preclinically using various implantable and injectable scaffold platforms. This review introduces the sustained-release formulations developed for localized cancer immunotherapy and highlights their biomaterial-based platforms for representative classes, including inorganic scaffolds, natural hydrogels, synthetic hydrogels, and microneedle patches. The design rationale and other considerations are summarized for further development of biomaterials for the construction of optimal sustained-release formulations.

A transdermal drug delivery system based on dissolving microneedles for boron neutron capture therapy of melanoma

Boron neutron capture therapy (BNCT) is a promising therapy for malignant tumors that requires selective and high concentrations of 10B accumulation in tumor cells. Despite ongoing developments in novel boron agents and delivery carriers, the progress and clinical application of BNCT is still restricted by the low 10B accumulation and tumor-to-normal tissue (T/N) ratio. Herein, a dissolving microneedle-based transdermal drug delivery system was specifically designed for BNCT in a mouse model of melanoma. By incorporating fructose-BPA (F-BPA) into PVA microneedle tips, this system successfully delivered sufficient F-BPA into the melanoma site after the application of only two patches. Notably, the T/N ratio achieved through the treatment combining PVA/F-BPA MNs with BNCT (PVA/F-BPA MNs-BNCT) surpassed 93.16, signifying a great improvement. Furthermore, this treatment approach effectively inhibited tumor growth and significantly enhanced the survival rate of the mice. In brief, our study introduces a novel, simple, and efficient administration strategy for BNCT, opening new possibilities for the design of nanomedicine for BNCT.

Advances in Polymeric Micelles: Responsive and Targeting Approaches for Cancer Immunotherapy in the Tumor Microenvironment

In recent years, to treat a diverse array of cancer forms, considerable advancements have been achieved in the field of cancer immunotherapies. However, these therapies encounter multiple challenges in clinical practice, such as high immune-mediated toxicity, insufficient accumulation in cancer tissues, and undesired off-target reactions. To tackle these limitations and enhance bioavailability, polymer micelles present potential solutions by enabling precise drug delivery to the target site, thus amplifying the effectiveness of immunotherapy. This review article offers an extensive survey of recent progress in cancer immunotherapy strategies utilizing micelles. These strategies include responsive and remodeling approaches to the tumor microenvironment (TME), modulation of immunosuppressive cells within the TME, enhancement of immune checkpoint inhibitors, utilization of cancer vaccine platforms, modulation of antigen presentation, manipulation of engineered T cells, and targeting other components of the TME. Subsequently, we delve into the present state and constraints linked to the clinical utilization of polymeric micelles. Collectively, polymer micelles demonstrate excellent prospects in tumor immunotherapy by effectively addressing the challenges associated with conventional cancer immunotherapies.

Microneedle-based cell delivery and cell sampling for biomedical applications

Cell-based therapeutics are novel therapeutic strategies that can potentially treat many presently incurable diseases through novel mechanisms of action. Cell therapies may benefit from the ease, safety, and efficacy of administering therapeutic cells. Despite considerable recent technological and biological advances, several barriers remain to the clinical translation and commercialization of cell-based therapies, including low patient compliance, personal handling inconvenience, poor biosafety, and limited biocompatibility. Microneedles (MNs) are emerging as a promising biomedical device option for improved cell delivery with little invasion, pain-free administration, and simplicity of disposal. MNs have shown considerable promise in treating a wide range of diseases and present the potential to improve cell-based therapies. In this review, we first summarized the latest advances in the various types of MNs developed for cell delivery and cell sampling. Emphasis was given to the design and fabrication of various types of MNs based on their structures and materials. Then we focus on the recent biomedical applications status of MNs-mediated cell delivery and sampling, including tissue repair (wound healing, heart repair, and endothelial repair), cancer treatment, diabetes therapy, cell sampling, and other applications. Finally, the current status of clinical application, potential perspectives, and the challenges for clinical translation are also highlighted.

Application of microneedles combined with dendritic cell-targeted nanovaccine delivery system in percutaneous immunotherapy for triple-negative breast cancer

This work aims at developing a strategy to activate the antigen-presenting cells to enhance the effect of immunotherapy in triple-negative breast cancer (TNBC) through the dissolving microneedle patch (DMNP). In present study, mannosylated chitosan (MCS) nanoparticles (NPs) were designed to target dendritic cells (DCs), and the immunotherapy effect was enhanced by the adjuvant Bacillus Calmette-Guerin polysaccharide (BCG-PSN), achieving the purpose of transdermal immunotherapy for TNBC. Vaccination studies with mice demonstrated that MCS NPs effectively induce DCs maturation in the tumor-draining lymph nodes to stimulate strong immune responses in TNBC. Overall, chitosan-based DMNPs with complex adjuvant constituted a new potent transdermal vaccine delivery platform capable of exploiting more DCs in the skin for effective immunization.

Biomaterial-based delivery platforms for transdermal immunotherapy

Nowadays, immunotherapy is one of the most essential treatments for various diseases and a broad spectrum of disorders are assumed to be treated by altering the function of the immune system. For this reason, immunotherapy has attracted a great deal of attention and numerous studies on different approaches for immunotherapies have been investigated, using multiple biomaterials and carriers, from nanoparticles (NPs) to microneedles (MNs). In this review, the immunotherapy strategies, biomaterials, devices, and diseases supposed to be treated by immunotherapeutic strategies are reviewed. Several transdermal therapeutic methods, including semisolids, skin patches, chemical, and physical skin penetration enhancers, are discussed. MNs are the most frequent devices implemented in transdermal immunotherapy of cancers (e.g., melanoma, squamous cell carcinoma, cervical, and breast cancer), infectious (e.g., COVID-19), allergic and autoimmune disorders (e.g., Duchenne's muscular dystrophy and Pollinosis). The biomaterials used in transdermal immunotherapy vary in shape, size, and sensitivity to external stimuli (e.g., magnetic field, photo, redox, pH, thermal, and even multi-stimuli-responsive) were reported. Correspondingly, vesicle-based NPs, including niosomes, transferosomes, ethosomes, microemulsions, transfersomes, and exosomes, are also discussed. In addition, transdermal immunotherapy using vaccines has been reviewed for Ebola, Neisseria gonorrhoeae, Hepatitis B virus, Influenza virus, respiratory syncytial virus, Hand-foot-and-mouth disease, and Tetanus.

Application of Nano-Delivery Systems in Lymph Nodes for Tumor Immunotherapy

Immunotherapy has become a promising research "hotspot" in cancer treatment. "Soldier" immune cells are not uniform throughout the body; they accumulate mostly in the immune organs such as the spleen and lymph nodes (LNs), etc. The unique structure of LNs provides the microenvironment suitable for the survival, activation, and proliferation of multiple types of immune cells. LNs play an important role in both the initiation of adaptive immunity and the generation of durable anti-tumor responses. Antigens taken up by antigen-presenting cells in peripheral tissues need to migrate with lymphatic fluid to LNs to activate the lymphocytes therein. Meanwhile, the accumulation and retaining of many immune functional compounds in LNs enhance their efficacy significantly. Therefore, LNs have become a key target for tumor immunotherapy. Unfortunately, the nonspecific distribution of the immune drugs in vivo greatly limits the activation and proliferation of immune cells, which leads to unsatisfactory anti-tumor effects. The efficient nano-delivery system to LNs is an effective strategy to maximize the efficacy of immune drugs. Nano-delivery systems have shown beneficial in improving biodistribution and enhancing accumulation in lymphoid tissues, exhibiting powerful and promising prospects for achieving effective delivery to LNs. Herein, the physiological structure and the delivery barriers of LNs were summarized and the factors affecting LNs accumulation were discussed thoroughly. Moreover, developments in nano-delivery systems were reviewed and the transformation prospects of LNs targeting nanocarriers were summarized and discussed.

Microneedle-mediated treatment for superficial tumors by combining multiple strategies

Superficial tumors are still challenging to overcome due to the high risk and toxicity of surgery and conventional chemotherapy. Microneedles (MNs) are widely used in the treatment of superficial skin tumors (SST) due to the high penetration rate of the stratum corneum (SC), excellent biocompatibility, simple preparation process, high patient compliance, and minimal invasion. Most importantly, MNs can provide not only efficient and rarely painful delivery carriers, but also combine multi-model strategies with photothermal therapy (PTT), immunotherapy, and gene therapy for synergistic efficacy. To promote an in-depth understanding of their superiorities, this paper systematically summarized the latest application progress of MNs in the treatment of SST by delivering various types of photosensitizers, immune signal molecules, genes, and chemotherapy drugs. Just as important, the advantages, limitations, and drug release mechanisms of MNs based on different materials are introduced in the paper. In addition, the application of MN technology to clinical practice is the ultimate goal of all the work. The obstacles and possible difficulties in expanding the production of MNs and achieving clinical transformation are briefly discussed in this paper. To be anticipated, our work will provide new insights into the precise and rarely painful treatment of SST in the future.

Biomaterials Facilitating Dendritic Cell-Mediated Cancer Immunotherapy

Dendritic cell (DC)-based cancer immunotherapy has exhibited remarkable clinical prospects because DCs play a central role in initiating and regulating adaptive immune responses. However, the application of traditional DC-mediated immunotherapy is limited due to insufficient antigen delivery, inadequate antigen presentation, and high levels of immunosuppression. To address these challenges, engineered biomaterials have been exploited to enhance DC-mediated immunotherapeutic effects. In this review, vital principal components that can enhance DC-mediated immunotherapeutic effects are first introduced. The parameters considered in the rational design of biomaterials, including targeting modifications, size, shape, surface, and mechanical properties, which can affect biomaterial optimization of DC functions, are further summarized. Moreover, recent applications of various engineered biomaterials in the field of DC-mediated immunotherapy are reviewed, including those serve as immune component delivery platforms, remodel the tumor microenvironment, and synergistically enhance the effects of other antitumor therapies. Overall, the present review comprehensively and systematically summarizes biomaterials related to the promotion of DC functions; and specifically focuses on the recent advances in biomaterial designs for DC activation to eradicate tumors. The challenges and opportunities of treatment strategies designed to amplify DCs via the application of biomaterials are discussed with the aim of inspiring the clinical translation of future DC-mediated cancer immunotherapies.

Sustained release hydrogel for durable locoregional chemoimmunotherapy for BRAF-mutated melanoma

The wide prevalence of BRAF mutations in diagnosed melanomas drove the clinical advancement of BRAF inhibitors in combination with immune checkpoint blockade for treatment of advanced disease. However, deficits in therapeutic potencies and safety profiles motivate the development of more effective strategies that improve the combination therapy's therapeutic index. Herein, we demonstrate the benefits of a locoregional chemoimmunotherapy delivery system, a novel thermosensitive hydrogel comprised of gelatin and Pluronic® F127 components already widely used in humans in both commercial and clinical products, for the co-delivery of a small molecule BRAF inhibitor with immune checkpoint blockade antibody for the treatment of BRAF-mutated melanoma. In vivo evaluation of administration route and immune checkpoint target effects revealed intratumoral administration of antagonistic programmed cell death protein 1 antibody (aPD-1) lead to potent antitumor therapy in combination with BRAF inhibitor vemurafenib. The thermosensitive F127-g-Gelatin hydrogel that was evaluated in multiple murine models of BRAF-mutated melanoma that facilitated prolonged local drug release within the tumor (>1 week) substantially improved local immunomodulation, tumor control, rates of tumor response, and animal survival. Thermosensitive F127-g-Gelatin hydrogels thus improve upon the clinical benefits of vemurafenib and aPD-1 in a locoregional chemoimmunotherapy approach for the treatment of BRAF-mutated melanoma.

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.

Supramolecular Dissolving Microneedle Patch Loading Hydrophobic Glucocorticoid for Effective Psoriasis Treatment

Glucocorticoid-based creams are commonly used for treatments of psoriatic skin lesions while showing poor permeation because the thickened stratum corneum severely limits drug absorption. Although dissolving microneedle (DMN) patches have been employed in treating skin disease by virtue of their direct target to the lesion site, conventional DMN patches are generally fabricated from the water-soluble matrix, making them difficult to efficiently encapsulate hydrophobic glucocorticoids. Here, we develop a mechanically robust supramolecular DMN composed of hydroxypropyl β-cyclodextrin (HPCD) to effectively and uniformly load triamcinolone acetonide (TA). The TA-loaded HPCD DMN (TAMN) exhibits excellent mechanical performance that can easily pierce the thickened psoriasis lesions and deliver TA efficiently. Owing to the increased water solubility and bioavailability of TA after inclusion into HPCD, TAMN shows a superior in vitro inhibitory effect on immortalized human keratinocyte (HaCaT) cells. Importantly, the administration of TAMN twice a week effectively alleviates psoriatic signs and reduces the expression of Ki67, IL-23, and IL-17 in the ear lesions of imiquimod-induced psoriasis-like mice. This supramolecular DMN provides a promising strategy for the efficient treatment of psoriasis and other skin diseases, greatly broadens the applications of supramolecular materials in transdermal drug delivery, and widens the range of drugs in DMNs.

Research progress of physical transdermal enhancement techniques in tumor therapy

The advancement and popularity of transdermal drug delivery (TDD) based on the physical transdermal enhancement technique (PTET) has opened a new paradigm for local tumor treatment. The drug can be directly delivered to the tumor site through the skin, thus avoiding the toxic side effects caused by the first-pass effect and achieving high patient compliance. Further development of PTETs has provided many options for antitumor drugs and laid the foundation for future applications of wearable closed-loop targeting drug delivery systems. In this highlight, the different types of PTETs and related mechanisms, and applications of PTET-related tumor detection and therapy are highlighted. According to their type and characteristics, PTETs are categorized as follows: (1) iontophoresis, (2) electroporation, (3) ultrasound, (4) thermal ablation, and (5) microneedles. PTET-related applications in the local treatment of tumors are categorized as follows: (1) melanoma, (2) breast tumor, (3) squamous cell carcinoma, (4) cervical tumor, and (5) others. The challenges and future prospects of existing PTETs are also discussed. This highlight will provide guidance for the design of PTET-based wearable closed-loop targeting drug delivery systems and personalized therapy for tumors.

Highly Prolonged Release of the Cancer Vaccine and Immunomodulator via a Two-Layer Biodegradable Microneedle for Prophylactic Treatment of Metastatic Cancer

Simultaneous sustained release of cancer vaccines and immunomodulators may effectively trigger durable immune responses and avoid multiple administrations. Here, we established a biodegradable microneedle (bMN) based on a biodegradable copolymer matrix made of polyethylene glycol (PEG) and poly(sulfamethazine ester urethane) (PSMEU). This bMN was applied to the skin and slowly degraded in the epidermis/dermis layers. Then, the complexes composed of a positively charged polymer (DA3), cancer DNA vaccine (pOVA), and toll-like receptor 3 agonist poly(I/C) were synchronously released from the matrix in a pain-free manner. The whole microneedle patch was fabricated with two layers. The basal layer was formed using polyvinyl pyrrolidone/polyvinyl alcohol that could be rapidly dissolved upon applying the microneedle patch to the skin, whereas the microneedle layer was formed by complexes encapsulating biodegradable PEG-PSMEU, which was stuck at the injection site for sustained release of therapeutic agents. According to the results, 10 days is the time for the complexes to be completely released and express specific antigens in antigen-presenting cells in vitro and in vivo. It is noteworthy that this system could successfully elicit cancer-specific humoral immune responses and inhibit metastatic tumors in the lungs after a single shot of immunization.

Demonstrating Biological Fate of Nanoparticle-Loaded Dissolving Microneedles with Aggregation-Caused Quenching Probes: Influence of Application Sites

Integrating dissolving microneedles (DMNs) and nanocarriers (NC) holds great potential in transdermal drug delivery because it can simultaneously overcome the stratum corneum barrier and achieve efficient and controlled drug delivery. However, different skin sites with different thicknesses and compositions can affect the transdermal diffusion of NC-loaded DMNs. There are few reports on the biological fate (especially transdermal diffusion) of NC-loaded DMNs, and inaccurate bioimaging information of intact NC limits the accurate understanding of the in vivo fate of NC-loaded DMNs. The aggregation-caused quenching (ACQ) probes P4 emitted intense fluorescence signals in intact NC while quenched after the degradation of NC, had been demonstrated the feasibility of label intact NC. In this study, P4 was loaded in solid lipid nanoparticles (SLNs), and further encapsulated into DMNs, to track the transdermal diffusion of SLNs delivered at different skin sites. The results showed that SLNs had excellent stability after being loaded into DMNs with no significant changes in morphology and fluorescence properties. The in vivo live and ex vivo imaging showed that the transdermal diffusion rate of NC-loaded DMNs was positively correlated with skin thickness, with the order ear > abdomen > back. In conclusion, this study confirmed the site-dependency of transdermal diffusion in NC-loaded DMNs.

Metallic Microneedles for Transdermal Drug Delivery: Applications, Fabrication Techniques and the Effect of Geometrical Characteristics

Current procedures for transdermal drug delivery (TDD) have associated limitations including poor administration of nucleic acid, small or large drug molecules, pain and stress for needle phobic people. A painless micro-sized device capable of delivering drugs easily and efficiently, eliminating the disadvantages of traditional systems, has yet to be developed. While polymeric-based microneedle (MN) arrays have been used successfully and clinically as TDD systems, these devices lack mechanical integrity, piercing capacity and the ability to achieve tailored drug release into the systemic circulation. Recent advances in micro/nano fabrication techniques using Additive Manufacturing (AM), also known as 3D printing, have enabled the fabrication of metallic MN arrays, which offer the potential to overcome the limitations of existing systems. This review summarizes the different types of MNs used in TDD and their mode of drug delivery. The application of MNs in the treatment of a range of diseases including diabetes and cancer is discussed. The potential role of solid metallic MNs in TDD, the various techniques used for their fabrication, and the influence of their geometrical characteristics (e.g., shape, size, base diameter, thickness, and tip sharpness) on effective TDD are explored. Finally, the potential and the future directions relating to the optimization of metallic MN arrays for TDD are highlighted.

Next-Generation 3D Scaffolds for Nano-Based Chemotherapeutics Delivery and Cancer Treatment

Cancer is the leading cause of death after cardiovascular disease. Despite significant advances in cancer research over the past few decades, it is almost impossible to cure end-stage cancer patients and bring them to remission. Adverse effects of chemotherapy are mainly caused by the accumulation of chemotherapeutic agents in normal tissues, and drug resistance hinders the potential therapeutic effects and curing of this disease. New drug formulations need to be developed to overcome these problems and increase the therapeutic index of chemotherapeutics. As a chemotherapeutic delivery platform, three-dimensional (3D) scaffolds are an up-and-coming option because they can respond to biological factors, modify their properties accordingly, and promote site-specific chemotherapeutic deliveries in a sustainable and controlled release manner. This review paper focuses on the features and applications of the variety of 3D scaffold-based nano-delivery systems that could be used to improve local cancer therapy by selectively delivering chemotherapeutics to the target sites in future.

Strong and Tough Supramolecular Microneedle Patches with Ultrafast Dissolution and Rapid-Onset Capabilities

Dissolving microneedle (DMN) patches are emerging as a minimally invasive and efficient transdermal drug delivery platform. Generally, noncrystalline, water-soluble, and high-molecular-weight polymers are employed in DMNs because their sufficient intermolecular interactions can endow the DMNs with necessary mechanical strength and toughness. However, high viscosity and heavy chain entanglement of polymer solutions greatly hinder processing and dissolution of polymeric DMNs. Here, a strong and tough supramolecular DMN patch made of highly water-soluble cyclodextrin (CD) derivatives is described. Due to the synergy of multiple supramolecular interactions, the CD DMN patch exhibits robust mechanical strength outperforming the state-of-the-art polymeric DMNs. The CD DMN displays ultrafast dissolution (<30 s) in skin models by virtue of the dynamic and weak noncovalent bonds, which also enables the CD DMN and its payloads to diffuse rapidly into the deep skin layer. Moreover, the unique supramolecular structure of CD allows the CD DMNs to load not only hydrophilic drugs (e.g., rhodamine B as a model) but also hydrophobic model drugs (e.g., ibuprofen). As a proof-of-concept, CD DMNs loading ibuprofen show a rapid onset of therapeutic action in a xylene-induced acute inflammation model in mice. This work opens a new avenue for the development of mechanically robust supramolecular DMNs and broadens the applications of supramolecular materials.

Recent Advances in Delivery Systems for Genetic and Other Novel Vaccines

Vaccination is one of the most successful and cost-effective prophylactic measures against diseases, especially infectious diseases including smallpox and polio. However, the development of effective prophylactic or therapeutic vaccines for other diseases such as cancer remains challenging. This is often due to the imprecise control of vaccine activity in vivo which leads to insufficient/inappropriate immune responses or short immune memory. The development of new vaccine types in recent decades has created the potential for improving the protective potency against these diseases. Genetic and subunit vaccines are two major categories of these emerging vaccines. Owing to their nature, they rely heavily on delivery systems with various functions, such as effective cargo protection, immunogenicity enhancement, targeted delivery, sustained release of antigens, selective activation of humoral and/or cellular immune responses against specific antigens, and reduced adverse effects. Therefore, vaccine delivery systems may significantly affect the final outcome of genetic and other novel vaccines and are vital for their development. This review introduces these studies based on their research emphasis on functional design or administration route optimization, presents recent progress, and discusses features of new vaccine delivery systems, providing an overview of this field.

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.

Engineered multifunctional nanocarriers for controlled drug delivery in tumor immunotherapy

The appearance of chemoresistance in cancer is a major issue. The main barriers to conventional tumor chemotherapy are undesirable toxic effects and multidrug resistance. Cancer nanotherapeutics were developed to get around the drawbacks of conventional chemotherapy. Through clinical evaluation of thoughtfully developed nano delivery systems, cancer nanotherapeutics have recently offered unmatched potential to comprehend and combat drug resistance and toxicity. In different design approaches, including passive targeting, active targeting, nanomedicine, and multimodal nanomedicine combination therapy, were successful in treating cancer in this situation. Even though cancer nanotherapy has achieved considerable technological development, tumor biology complexity and heterogeneity and a lack of full knowledge of nano-bio interactions remain important hurdles to future clinical translation and commercialization. The recent developments and advancements in cancer nanotherapeutics utilizing a wide variety of nanomaterial-based platforms to overcome cancer treatment resistance are covered in this article. Additionally, an evaluation of different nanotherapeutics-based approaches to cancer treatment, such as tumor microenvironment targeted techniques, sophisticated delivery methods for the precise targeting of cancer stem cells, as well as an update on clinical studies are discussed. Lastly, the potential for cancer nanotherapeutics to overcome tumor relapse and the therapeutic effects and targeted efficacies of modern nanosystems are analyzed.

The role of imaging in targeted delivery of nanomedicine for cancer therapy

Nanomedicines overcome the pharmacokinetic limitations of traditional drug formulations and have promising prospect in cancer treatment. However, nanomedicine delivery in vivo is still facing challenges from the complex physiological environment. For the purpose of effective tumor therapy, they should be designed to guarantee the five features principle, including long blood circulation, efficient tumor accumulation, deep matrix penetration, enhanced cell internalization and accurate drug release. To ensure the excellent performance of the designed nanomedicine, it would be better to monitor the drug delivery process as well as the therapeutic effects by real-time imaging. In this review, we summarize strategies in developing nanomedicines for efficiently meeting the five features of drug delivery, and the role of several imaging modalities (fluorescent imaging (FL), magnetic resonance imaging (MRI), computed tomography (CT), photoacoustic imaging (PAI), positron emission tomography (PET), and electron microscopy) in tracing drug delivery and therapeutic effect in vivo based on five features principle.

Recent Advancements in Microneedle Technology for Multifaceted Biomedical Applications

Microneedle (MNs) technology is a recent advancement in biomedical science across the globe. The current limitations of drug delivery, like poor absorption, low bioavailability, inadequate skin permeation, and poor biodistribution, can be overcome by MN-based drug delivery. Nanotechnology made significant changes in fabrication techniques for microneedles (MNs) and design shifted from conventional to novel, using various types of natural and synthetic materials and their combinations. Nowadays, MNs technology has gained popularity worldwide in biomedical research and drug delivery technology due to its multifaceted and broad-spectrum applications. This review broadly discusses MN’s types, fabrication methods, composition, characterization, applications, recent advancements, and global intellectual scenarios.

Potential of Microneedle Systems for COVID-19 Vaccination: Current Trends and Challenges

To prevent the coronavirus disease 2019 (COVID-19) pandemic and aid restoration to prepandemic normality, global mass vaccination is urgently needed. Inducing herd immunity through mass vaccination has proven to be a highly effective strategy for preventing the spread of many infectious diseases, which protects the most vulnerable population groups that are unable to develop immunity, such as people with immunodeficiencies or weakened immune systems due to underlying medical or debilitating conditions. In achieving global outreach, the maintenance of the vaccine potency, transportation, and needle waste generation become major issues. Moreover, needle phobia and vaccine hesitancy act as hurdles to successful mass vaccination. The use of dissolvable microneedles for COVID-19 vaccination could act as a major paradigm shift in attaining the desired goal to vaccinate billions in the shortest time possible. In addressing these points, we discuss the potential of the use of dissolvable microneedles for COVID-19 vaccination based on the current literature.

Advanced Biomaterials for Cell-Specific Modulation and Restore of Cancer Immunotherapy

The past decade has witnessed the explosive development of cancer immunotherapies. Nevertheless, low immunogenicity, limited specificity, poor delivery efficiency, and off-target side effects remain to be the major limitations for broad implementation of cancer immunotherapies to patient bedside. Encouragingly, advanced biomaterials offering cell-specific modulation of immunological cues bring new solutions for improving the therapeutic efficacy while relieving side effect risks. In this review, focus is given on how functional biomaterials can enable cell-specific modulation of cancer immunotherapy within the cancer-immune cycle, with particular emphasis on antigen-presenting cells (APCs), T cells, and tumor microenvironment (TME)-resident cells. By reviewing the current progress in biomaterial-based cancer immunotherapy, here the aim is to provide a better understanding of biomaterials' role in targeting modulation of antitumor immunity step-by-step and guidelines for rationally developing targeting biomaterials for more personalized cancer immunotherapy. Moreover, the current challenge and future perspective regarding the potential application and clinical translation will also be discussed.

Exosome-mediated delivery of transforming growth factor-β receptor 1 kinase inhibitors and toll-like receptor 7/8 agonists for combination therapy of tumors

In this study, combination therapy with the transforming growth factor-β receptor I (TGFβRI) kinase inhibitor SD-208 and a toll-like receptor (TLR)-7/8 agonist resiquimod (R848) was examined along with serum-derived exosomes (EXOs) as versatile carriers. SD-208-encapsulated EXOs (SD-208/EXOs) and R848-encapsulated EXOs (R848/EXOs) were successfully prepared with a size of 87 ± 8 nm and 51 ± 4 nm, respectively, which were stable in aqueous solution at pH 7.4. SD-208/EXOs and R848/EXOs reduced the migration of cancer cells (B16F10 and PC-3) and triggered the release of proinflammatory cytokines from stimulated macrophages and dendritic cells, respectively. The fluorescent dye-labeled EXOs showed significantly improved penetration through the PC-3/fibroblast co-culture spheroids and enhanced accumulation in the B16F10 mouse tumor model compared with the free fluorescent dye. In addition, the combination therapy of R848/EXOs (R848 dose of 0.36 mg/kg) and SD-208/EXOs (SD-208 dose of 0.75 mg/kg) reduced tumor growth and improved survival rate at low doses in the B16F10 tumor xenograft model. Taken together, the combination therapy using the TGFβRI kinase inhibitor and TLR 7/8 agonist with EXOs may serve as a promising strategy to treat melanoma and prostate cancer. STATEMENT OF SIGNIFICANCE: Owing to the prevalence of several non-responding cancers that resist treatment, it is necessary to identify a novel combined treatment strategy with biomaterials to maximize therapeutic efficacy and minimize the undesirable side effects. In this study, we aimed to examine the use of the TGFβRI kinase inhibitor SD-208 and the TLR7/8 agonist resiquimod (R848) encapsulated within serum-derived EXOs for their synergistic antitumor effects. We first demonstrated that combined treatment with SD-208 and R848 can be a convincing strategy to circumvent tumor growth in vivo using serum-derived exosomes as promising carriers. Therefore, we believe this manuscript would be of great interest to the biomaterial communities especially who are studying immunotherapy.

Microneedle-Based Natural Polysaccharide for Drug Delivery Systems (DDS): Progress and Challenges

In this focused progress review, the most widely accepted methods of transdermal drug delivery are hypodermic needles, transdermal patches and topical creams. However, microneedles (MNs) (or microneedle arrays) are low-invasive 3D biomedical constructs that bypass the skin barrier and produce systemic and localized pharmacological effects. In the past, biomaterials such as carbohydrates, due to their physicochemical properties, have been extensively used to manufacture microneedles (MNs). Due to their wide range of functional groups, carbohydrates enable the design and development of tunable properties and functionalities. In recent years, numerous microneedle products have emerged on the market, although much research needs to be undertaken to overcome the various challenges before the successful introduction of microneedles into the market. As a result, carbohydrate-based microarrays have a high potential to achieve a future step in sensing, drug delivery, and biologics restitution. In this review, a comprehensive overview of carbohydrates such as hyaluronic acid, chitin, chitosan, chondroitin sulfate, cellulose and starch is discussed systematically. It also discusses the various drug delivery strategies and mechanical properties of biomaterial-based MNs, the progress made so far in the clinical translation of carbohydrate-based MNs, and the promotional opportunities for their commercialization. In conclusion, the article summarizes the future perspectives of carbohydrate-based MNs, which are considered as the new class of topical drug delivery systems.

Microneedle Array Patch Made of Kangfuxin/Chitosan/Fucoidan Complex Enables Full-Thickness Wound Healing

Skin wound caused by external injury is usually difficult to be cured by conventional topical administration because of its poor drug diffusion across the stratum corneum. It has been recognized that stratum corneum is the major obstacle for transdermal drug delivery. To address this issue, microneedles (MNs) have been developed to penetrate the stratum corneum of the skin and then form micron-sized pores between the epidermis and the dermis layers. As such, biomacromolecule drugs and/or insoluble drug molecules can be allowed for effective transdermal penetration. A multifunctional microneedle array patch that can avoid wound infection and promote tissue remolding has important value for wound healing. Among others, marine polysaccharides have attracted much attention in multifarious biomedical applications due to their excellent (bio)physical and chemical properties. Herein, we developed a microneedle array patch using a blend of kangfuxin (KFX), chitosan (CS), and fucoidan (FD), named KCFMN, for accelerating full-thickness wound healing. The traditional Chinese medicine KFX extracted from Periplaneta americana (PA) has effective bio-functions in promoting wound healing. The macro-/micro-morphology and (bio)physicochemical properties of such composite microneedles were also studied. We showed that the KCFMN patch displayed noticeable antibacterial properties and good cytocompatibility. In particular, the KCFMN patch significantly accelerated the wound healing development in a full-thickness wound in rats by improving the epithelial thickness and collagen deposition. Thus, this versatile KCFMN patch has great prospects as a dressing for full-thickness wound healing.

Lyotropic liquid crystal-based transcutaneous peptide delivery system: Evaluation of skin permeability and potential for transcutaneous vaccination

Transcutaneous drug delivery is a promising method in terms of drug repositioning and reformulation because of its non-invasive and easy-to-use features. To overcome the skin barrier, which is the biggest challenge in transcutaneous drug delivery, a number of techniques, such as microemulsion, solid-in-oil dispersions and liposomes, have been studied extensively. However, the low viscosity of these formulations limits drug retention on the skin and reduces patient acceptability. Although viscosity can be increased by adding a thickening reagent, such an addition often alters formulation nanostructures and drug solubility, and importantly, decreases skin permeability. In this study, a gel-like lyotropic liquid crystal (LLC) was used as a tool to enhance skin permeability. In particular, we prepared 1-monolinolein (ML)-based LLCs with different water contents. All LLCs significantly enhanced skin permeation of a peptide drug, an epitope peptide of melanoma, despite their high viscoelasticity. Fourier transform infra-red spectroscopic analysis of the skin surface treated with the LLCs revealed that the gyroid geometry more strongly interacted with the lamellar structure inside the stratum corneum (SC) than the diamond geometry. Finally, as the result of the in vivo tumor challenge experiment using B16F10 melanoma-bearing mice, the LLC with the gyroid geometry showed stronger vaccine effect against tumor than a subcutaneous injection. Collectively, ML-based LLCs, especially with the gyroid geometry, are a promising strategy to deliver biomacromolecules into skin. STATEMENT OF SIGNIFICANCE: Transcutaneous drug delivery is a promising method for drug repositioning and reformulation because of its non-invasive and easy-to-use features. To overcome the skin barrier, which is the biggest challenge in transcutaneous drug delivery, we used a gel-like lyotropic liquid crystal (LLC) as a novel tool to enhance skin permeability. In this paper, we demonstrated that an LLC with a specific liquid crystalline structure has the highest skin permeation enhancement effect for a peptide antigen as a model drug. Moreover, the peptide antigen-loaded LLC showed a vaccine effect that was comparable to a subcutaneous injection in vivo. This study provides a basis for designing a transcutaneous delivery system of peptide drugs with LLC.

Amalgamated Microneedle Array Bearing Ribociclib-Loaded Transfersomes Eradicates Breast Cancer via CD44 Targeting

HR+/HER2- metastatic breast cancer (MBC) is one of the most common and life-threatening conditions diagnosed in women. The endocrine therapy using an orally active CDK4/6 inhibitor, ribociclib (RB), is the most intriguing approach for treating HR+/HER2- MBC. However, the repeated three to six cycles of multiple dosing and non-targeted distribution of RB led to severe neutropenia; hepatobiliary, gastrointestinal, and renal toxicities, and QT interval prolongation. Here, a novel organic solvent-free HA-PVA-PVP (hyaluronic acid-polyvinyl alcohol-polyvinyl pyrrolidone) composed of a microneedle (MN) array is formulated to deliver RB, integrated with amphiphilic conjugated polymer (HA-GMS)-anchored ultradeformable transfersomes. This unique MN array efficiently crafts microchannels in the skin, allowing HA-RB-Ts to internalize into the tumor cells through lymphatic and systemic absorption and interact with CD44 both spatially and temporally with an amplification of drug release time up to 6-folds. The pharmacokinetic and tissue distribution studies portray drug concentrations within the therapeutic window as long as 48 h, facilitating thrice-a-week frequency with the lower dose, and rule out severe toxicities, with a significant reduction in 8.3-fold RB concentration in vital organs that ultimately enhances the survival rate. Thus, the novel MN system pursues a unique embeddable feature and offers an effective, self-administrable, biodegradable, and chronic treatment option for patients requiring long-term cancer treatments.

Bioinspired and Biomimetic Delivery Platforms for Cancer Vaccines

Cancer vaccines aim at eliciting tumor-specific responses for the immune system to identify and eradicate malignant tumor cells while sparing the normal tissues. Furthermore, cancer vaccines can potentially induce long-term immunological memory for antitumor responses, preventing metastasis and cancer recurrence, thus presenting an attractive treatment option in cancer immunotherapy. However, clinical efficacy of cancer vaccines has remained low due to longstanding challenges, such as poor immunogenicity, immunosuppressive tumor microenvironment, tumor heterogeneity, inappropriate immune tolerance, and systemic toxicity. Recently, bioinspired materials and biomimetic technologies have emerged to play a part in reshaping the field of cancer nanomedicine. By mimicking desirable chemical and biological properties in nature, bioinspired engineering of cancer vaccine delivery platforms can effectively transport therapeutic cargos to tumor sites, amplify antigen and adjuvant bioactivities, and enable spatiotemporal control and on-demand immunoactivation. As such, integration of biomimetic designs into delivery platforms for cancer vaccines can enhance efficacy while retaining good safety profiles, which contributes to expediting the clinical translation of cancer vaccines. Recent advances in bioinspired delivery platforms for cancer vaccines, existing obstacles faced, as well as insights and future directions for the field are discussed here.

Microneedle-mediated transdermal nanodelivery systems: a review

The greatest limitation in the development of transdermal drug delivery systems is that only a few drugs can permeate the skin due to the barrier function of the stratum corneum. Active and passive methods are generally available for improving the ability of drug transdermal delivery. However, nanoparticles, as a passive approach, exhibit capacity-constrained permeation enhancement. Thus, microneedle-mediated nanoparticles possess enormous potential and broad prospects. Microneedles promote the penetration of macromolecules by creating microchannels on the skin surface. In this review, the prevailing subknowledge on microneedles (mechanism, classification, and applications of microneedles combined with nanoparticles) is discussed to provide a guideline for readers and a basic reference for further in-depth studies of this novel drug delivery system.

Transdermal Drug delivery: A step towards treatment of cancer

BACKGROUND

Transdermal drug delivery is an emerging and tempting system over oral and hypodermic drug delivery system. With the new developments in skin penetration techniques, anticancer drugs ranging from hydrophilic macromolecules to lipophilic drugs can be administered via transdermal route to treat cancer.

OBJECTIVE

In the present review, various approaches to enhance the transdermal delivery of drugs is discussed including the micro and nanotechnology based transdermal formulations like chemotherapy, gene therapy, immunotherapy, phototherapy, vaccines and medical devices. Limitations and advantages of various transdermal technologies is also elaborated.

METHOD

In this review, patent applications and recent literature of transdermal drug delivery systems employed to cure mainly cancer are covered.

RESULTS

Transdermal drug delivery systems have proved their potential to cure cancer. They increase the bioavailability of drug by site specific drug delivery and can reduce the side effects/toxicity associated with anticancer drugs.

CONCLUSION

The potential of transdermal drug delivery systems to carry the drug may unclutter novel ways for therapeutic intercessions in various tumors.

Dissolving microneedle-assisted long-acting Liraglutide delivery to control type 2 diabetes and obesity

Integrating nanoparticles (NPs) as a smart and targeted tool for drug delivery with dissolving microneedle (DMN) patch, the non-invasive device for drug delivery, is a promising for future therapeutic delivery applications. Liraglutide (Lira) encapsulation in poly (lactic-co-glycolic acid) (PLGA) NPs provides a sustained release of Lira to 15 days in a biphasic profile which 80% of released content happens in the first 8 days. Embedding such sustained release NPs in the DMN comprising poly vinyl pyrrolidone (PVP) 50% w/v, eliminates the need for Lira subcutaneous injection. Additionally, NPs containing DMN enhance mechanical strength of needles to 5.31 N compared to DMN with pure Lira content which was 4.32 N. The flexible backing layer of the DMN was obtained via blending of PVP and poly vinyl alcohol (PVA) in 10% w/v. Circular dichroism (CD) analysis showed that Lira encapsulated in NPs maintained its native secondary structure even after solidification in DMN. In this study, the capacity of 2 kinds of 500 μm and 1000 μm needles to deliver the desired dose of drug was obtained based on experimental and mathematical methods.

Innovations in lymph node targeting nanocarriers

Lymph nodes are secondary lymphoid tissues in the body that facilitate the co-mingling of immune cells to enable and regulate the adaptive immune response. They are also tissues implicated in a variety of diseases, including but not limited to malignancy. The ability to access lymph nodes is thus attractive for a variety of therapeutic and diagnostic applications. As nanotechnologies are now well established for their potential in translational biomedical applications, their high relevance to applications that involve lymph nodes is highlighted. Herein, established paradigms of nanocarrier design to enable delivery to lymph nodes are discussed, considering the unique lymph node tissue structure as well as lymphatic system physiology. The influence of delivery mechanism on how nanocarrier systems distribute to different compartments and cells that reside within lymph nodes is also elaborated. Finally, current advanced nanoparticle technologies that have been developed to enable lymph node delivery are discussed.

Strategy and clinical application of up-regulating cross presentation by DCs in anti-tumor therapy

The cross presentation of exogenous antigen (Ag) by dendritic cells (DCs) facilitates a diversified mode of T-cell activation, orchestrates specific humoral and cellular immunity, and contributes to an efficient anti-tumor immune response. DCs-mediated cross presentation is subject to both intrinsic and extrinsic factors, including the homing and phenotype of DCs, the spatiotemporal trafficking and degradation kinetics of Ag, and multiple microenvironmental clues, with many details largely unexplored. Here, we systemically review the current mechanistic understanding and regulation strategies of cross presentation by heterogeneous DC populations. We also provide insights into the future exploitation of DCs cross presentation for a better clinical efficacy in anti-tumor therapy.

Microneedles in Drug Delivery: Progress and Challenges

In recent years, an innovative transdermal delivery technology has attracted great interest for its ability to distribute therapeutics and cosmeceuticals for several applications, including vaccines, drugs, and biomolecules for skin-related problems. The advantages of microneedle patch technology have been extensively evaluated in the latest literature; hence, the academic publications in this area are rising exponentially. Like all new technologies, the microneedle patch application has great potential but is not without limitations. In this review, we will discuss the possible limitations by highlighting the areas where a great deal of improvements are required. Emphasising these concerns early on should help scientists and technologists to address the matters in a timely fashion and to use their resources wisely.

Recent advances in microneedles-based drug delivery device in the diagnosis and treatment of cancer

Microneedles are unique, novel and an effective approach designed to deliver therapeutic agents and immunobiologicals in several diseases. These tiny needle patches are designed to load vaccine, small or large drug molecule, heavy molecular weighted proteins, genes, antibodies, nanoparticles and many more. These nanoparticles loaded microneedles deliver drugs deep within the skin near underlying neutrophils, langerhans and dendritic cells and induces required immunological response. With the drawbacks associated with conventional methods of cancer chemotherapy, the focus was shifted towards use of microneedles in not just anti-cancer vaccine/drug delivery but also for their early diagnosis. This delivery device is also suited for synergistic approaches such as chemotherapy or gene therapy combined with photothermal or photodynamic therapy. The painless self-administrative device offers an alternative over traditional routes of drug delivery including systemic administration via hypodermic needles. Additionally, these microneedles can be fabricated and altered in shape, size and geometry and the material polymer can be chosen depending on use and release mechanism. This review consolidates positive results obtained from studies done for different type of microneedle array in several tumor cell lines and animal models. It further highlights the use of biodegradable polymers such as hydrogel or any dissolving polymer that can be utilized for sustained codelivery of drug/vaccine to shun the need of multiple dosing. It covers the existing limitations that still needs to be resolved and further highlights on the future aspects of their use in cancer therapy.