Patchless administration of canine influenza vaccine on dog's ear using insertion-responsive microneedles (IRMN) without removal of hair and its in vivo efficacy evaluation

Development and Evaluation of Five-in-One Vaccine Microneedle Array Patch for Diphtheria, Tetanus, Pertussis, Hepatitis B, and Haemophilus influenzae Type b: Immunological Efficacy and Long-Term Stability

Background and objectives: The development of a five-in-one vaccine microneedle patch (five-in-one MN patch) aims to address challenges in administering vaccines against Diphtheria (DT), Tetanus (TT), Pertussis (wP), Hepatitis B (HBsAg), and Haemophilus influenzae type b (Hib). Combining multiple vaccines into a single patch offers a novel solution to improve vaccine accessibility, stability, and delivery efficiency, particularly in resource-limited settings. Methods: The five-in-one MN patch consists of four distinct microneedle arrays: DT and TT vaccines are coated together on one array, while wP, HepB, and Hib vaccines are coated separately on individual arrays. The patch was tested for long-term stability (12 months at 25 °C) and evaluated for immunogenicity in mice and minipigs. Antibody titers were measured using ELISA to compare immune responses between microneedle-based delivery and traditional intramuscular (IM) injection. Results: The five-in-one MN patch demonstrated stable antigenicity for up to 12 months at room temperature. In animal studies, the patch induced antibody titers comparable to traditional IM injections for all vaccines. Notably, immunogenic responses to Pertussis and Haemophilus influenzae type b vaccines via microneedles were reported for the first time. The patch facilitated the simultaneous yet independent delivery of vaccines, preserving their immunogenicity without interference. Conclusions: The five-in-one MN patch represents a significant advancement in vaccine delivery by enabling stable, minimally invasive, and efficient immunization. Its innovative design addresses the critical limitations of combination vaccines and has the potential to enhance vaccine accessibility in low- and middle-income countries. Future studies will focus on optimizing patch application techniques and evaluating broader clinical applicability.

Porous Microneedles for Therapy and Diagnosis: Fabrication and Challenges

The use of microneedles (MNs), an innovative transdermal technology, enables efficient, convenient, painless, and controlled-release drug delivery. Porous microneedles (pMNs), special MNs with abundant interconnected pores that can produce capillary action, are gaining increasing attention as a novel MNs technology. pMNs can actively adsorb bioactive ingredients from solutions of drugs or vaccines for in vivo delivery or from interstitial skin fluids (ISFs) for wearable and point-of-care testing (POCT) products. Different pore sizes and porosities of pMNs can be achieved with different materials and preparation processes, which makes the application of pMNs adaptable to multiple scenarios. In addition, easier and faster detection will be accomplished by the smart combination of pMNs with other detection technologies. This paper aims to summarize the recent research progress of pMNs, focusing on the influence of various materials and their corresponding preparation methods on its structure and function display, discussing the key issues and looking forward to the future development.

Application of microneedle patches for drug delivery; doorstep to novel therapies

In the past decade, microneedle-based drug delivery systems showed promising approaches to become suitable and alternative for hypodermic injections and can control agent delivery without side effects compared to conventional approaches. Despite these advantages, the procedure of microfabrication is facing some difficulties. For instance, drug loading method, stability of drugs, and retention time are subjects of debate. Besides, the application of novel refining fabrication methods, types of materials, and instruments are other issues that need further attention. Herein, we tried to summarize recent achievements in controllable drug delivery systems (microneedle patches) in vitro and in vivo settings. In addition, we discussed the influence of delivered drugs on the cellular mechanism and immunization molecular signaling pathways through the intradermal delivery route. Understanding the putative efficiency of microneedle patches in human medicine can help us develop and design sophisticated therapeutic modalities.

The Ethics of Innovation: Ethical Decision-Making and Review for Field Studies and Projects Targeting Dogs and Cats

Simple Summary

Innovation and research to advance animal welfare, particularly that of companion animal species, can present unique ethical challenges, and there are presently gaps in support and independent oversight structures for ethical decision-making. This commentary details key gaps and one organization’s creation of an Ethical Review Board and structure for ethical review to help address them.

Abstract

To date, independent ethical oversight of many companion animal welfare initiatives has been limited and, in some instances, inadequate. Beyond a blurred line between “innovation” and “research,” the nature of the work conducted in animal welfare projects is often poorly aligned with established institutional ethical review structures, which are designed for research involving humans or research involving animals and are also focused on industry and academic institutions. This commentary details the struggle of one United States-based nonprofit organization to find ethical guidelines and support for conducting non-traditional field-based animal welfare studies, and subsequent experience establishing an Ethical Review Board to evaluate organizational initiatives. The commentary discusses member selection, materials and processes, and lessons and learnings from the creation and use of an Ethical Review Board. Sharing content of the ethical review process, as well as challenges and learnings from it, is intended to support other organizations and individuals seeking to ensure that innovation for animal welfare consistently meets high ethical standards.

Microneedles for drug delivery: recent advances in materials and geometry for preclinical and clinical studies

INTRODUCTION

A microneedle array patch (MAP) has been studied as a means for delivering drugs or vaccines and has shown superior delivery efficiency compared to the conventional transdermal drug delivery system (TDD). This paper reviews recent advancements in the development of MAPs, with a focus on their size, shapes, and materials in preclinical and clinical studies for pharmaceutics.

AREA COVERED

We classified MAPs for drug delivery into four types: coated, dissolving, separable, and swellable. We covered their recent developments in materials and geometry in preclinical and clinical studies.

EXPERT OPINION

The design of MAPs needs to be determined based on what properties would be effective for the target diseases and purposes. In addition, in preclinical studies, it is necessary to consider not only the novelty of the formulations but also the feasibility of clinical application. Currently, clinical studies of microneedles loaded with various drugs and vaccines are in progress. When the regulation of pharmaceutical microneedles is established and more clinical studies are published, more drugs will be developed as microneedle products and clinical research will proceed. With these considerations, the microneedle array patch will be a better option for drug delivery.

Microneedles: A New Generation Vaccine Delivery System

Transdermal vaccination route using biodegradable microneedles is a rapidly progressing field of research and applications. The fear of painful needles is one of the primary reasons most people avoid getting vaccinated. Therefore, developing an alternative pain-free method of vaccination using microneedles has been a significant research area. Microneedles comprise arrays of micron-sized needles that offer a pain-free method of delivering actives across the skin. Apart from being pain-free, microneedles provide various advantages over conventional vaccination routes such as intramuscular and subcutaneous. Microneedle vaccines induce a robust immune response as the needles ranging from 50 to 900 μm in length can efficiently deliver the vaccine to the epidermis and the dermis region, which contains many Langerhans and dendritic cells. The microneedle array looks like band-aid patches and offers the advantages of avoiding cold-chain storage and self-administration flexibility. The slow release of vaccine antigens is an important advantage of using microneedles. The vaccine antigens in the microneedles can be in solution or suspension form, encapsulated in nano or microparticles, and nucleic acid-based. The use of microneedles to deliver particle-based vaccines is gaining importance because of the combined advantages of particulate vaccine and pain-free immunization. The future of microneedle-based vaccines looks promising however, addressing some limitations such as dosing inadequacy, stability and sterility will lead to successful use of microneedles for vaccine delivery. This review illustrates the recent research in the field of microneedle-based vaccination.

Engineering Microneedle Patches for Improved Penetration: Analysis, Skin Models and Factors Affecting Needle Insertion

Transdermal microneedle (MN) patches are a promising tool used to transport a wide variety of active compounds into the skin. To serve as a substitute for common hypodermic needles, MNs must pierce the human stratum corneum (~ 10 to 20 µm), without rupturing or bending during penetration. This ensures that the cargo is released at the predetermined place and time. Therefore, the ability of MN patches to sufficiently pierce the skin is a crucial requirement. In the current review, the pain signal and its management during application of MNs and typical hypodermic needles are presented and compared. This is followed by a discussion on mechanical analysis and skin models used for insertion tests before application to clinical practice. Factors that affect insertion (e.g., geometry, material composition and cross-linking of MNs), along with recent advancements in developed strategies (e.g., insertion responsive patches and 3D printed biomimetic MNs using two-photon lithography) to improve the skin penetration are highlighted to provide a backdrop for future research.

Emerging skin-targeted drug delivery strategies to engineer immunity: A focus on infectious diseases

INTRODUCTION

Infectious pathogens are global disrupters. Progress in biomedical science and technology has expanded the public health arsenal against infectious diseases. Specifically, vaccination has reduced the burden of infectious pathogens. Engineering systemic immunity by harnessing the cutaneous immune network has been particularly attractive since the skin is an easily accessible immune-responsive organ. Recent advances in skin-targeted drug delivery strategies have enabled safe, patient-friendly, and controlled deployment of vaccines to cutaneous microenvironments for inducing long-lived pathogen-specific immunity to mitigate infectious diseases, including COVID-19.

AREAS COVERED

This review briefly discusses the basics of cutaneous immunomodulation and provides a concise overview of emerging skin-targeted drug delivery systems that enable safe, minimally invasive, and effective intracutaneous administration of vaccines for engineering systemic immune responses to combat infectious diseases.

EXPERT OPINION

In-situ engineering of the cutaneous microenvironment using emerging skin-targeted vaccine delivery systems offers remarkable potential to develop diverse immunization strategies against pathogens. Mechanistic studies with standard correlates of vaccine efficacy will be important to compare innovative intracutaneous drug delivery strategies to each other and to existing clinical approaches. Cost-benefit analyses will be necessary for developing effective commercialization strategies. Significant involvement of industry and/or government will be imperative for successfully bringing novel skin-targeted vaccine delivery methods to market for their widespread use.

Microneedles for Extended Transdermal Therapeutics: A Route to Advanced Healthcare

Sustained release of drugs over a pre-determined period is required to maintain an effective therapeutic dose for variety of drug delivery applications. Transdermal devices such as polymeric microneedle patches and other microneedle-based devices have been utilized for sustained release of their payload. Swift clearing of drugs can be prevented either by designing a slow-degrading polymeric matrix or by providing physiochemical triggers to different microneedle-based devices for on-demand release. These long-acting transdermal devices prevent the burst release of drugs. This review highlights the recent advances of microneedle-based devices for sustained release of vaccines, hormones, and antiretrovirals with their prospective safe clinical translation.