Advances in microneedles for non-transdermal applications

ABSTRACT

Introduction

Microneedles (MNs) have emerged as a promising tool for various therapeutic and diagnostic applications. While MNs have been prominently used for transdermal applications, recent advances in materials science, microfabrication technologies, and clinical devices enable the expansion of MNs to diverse non-transdermal applications.

Areas covered

This review provides an overview of recent advances in the MN technology for non-transdermal applications. The classification of MNs and their applications to ocular, vascular, oral, mucosal, and cancer tissues are particularly highlighted.

Expert opinion

Recent efforts in MN designs have enabled and broadened MNs to many non-transdermal applications. It is anticipated to witness many new MN-mediated non-transdermal applications in the near future. By advancing MN systems with suitable properties for target tissues, it is possible to achieve high drug delivery efficiency that outperforms traditional drug delivery methods. Further endeavors in translation and commercialization of these novel technologies are equally critical.

KEYWORDS:

• Microneedles
• drug delivery
• non-transdermal

Article highlights

• Coated, hollow, dissolvable, and biodegradable MNs have been explored for non-transdermal applications.

• MNs for oral mucosa delivery have been investigated for therapeutic (diabetes mellitus, local anesthesia, and oral carcinomas) and vaccine applications.

• MNs for ocular delivery can be applied to both anterior and posterior segments.

• MN-mediated cell therapy and gene therapy have been utilized to treat heart-related diseases.

• MN-bearing devices were invented to deliver drugs from the exterior or interior surface of blood vessels.

• MNs have been shown improved the delivery efficiency of biomacromolecules in the gastrointestinal tract.

This box summarizes key points contained in the article.

Declaration of interests

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was funded by Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Program (RGPIN-2021-02669) (GC) and the start-up package of McGill University (GC).