Research progress on detachable microneedles for advanced applications

ABSTRACT

Introduction

Microneedles (MNs) have undergone great advances in transdermal drug delivery, and commercialized MN applications are currently available in vaccination and cosmetic products. Despite the development of MN technologies, common limitations of MN products still exist. Typical MN patches are applied to target tissues, where the substrate of an MN patch must remain until the drug is delivered, which reduces patients’ compliance and hinders the applicability of the MN technique to many diseases in various tissues. MN research is ongoing to solve this issue.

Areas covered

Most recent MNs developed by combining various biomaterials with appropriate fabrication processes are detachable MNs (DeMNs). Because of advances in biomaterials and fabrication techniques, various DeMNs have been rapidly developed. In this review, we discuss four types of DeMN: substrate-separable, multi-layered, crack-inducing, and shell DeMN. These DeMNs deliver various therapeutic agents ranging from small- and large-molecular-weight drugs to proteins and even stem cells for regeneration therapy. Furthermore, DeMNs are applied to skin as well as non-transdermal tissues.

Expert opinion

It has become increasingly evident that novel MN technologies can be expected in terms of designs, fabrication methods, materials, and even possible application sites given the recent advances in DeMNs.

KEYWORDS:

• detachable microneedles
• microfabrication
• advanced molding
• therapeutic agents
• separation mechanism

Article highlights

• Most recent MNs developed by combining various biomaterials with appropriate fabrication processes are DeMNs.

• Various biomaterials suitable for proteins or cells with high viability have been developed, and DeMNs developed using such materials are introduced in this review.

• Various types of DeMNs have been developed for quick and reliable separation between drug-loaded MNs and backing substrates.

• Significantly decreasing the application time of the DeMN patch reduces the discomfort of the patient, which has been identified as a current limitation.

• Novel DeMN drug-delivery techniques that have not been developed before are proposed because the use of biomaterials in DeMNs facilitates incorporating proteins and stem cells as well as small- and large-molecular-weight drugs.

Declaration of interest

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 work was supported by Global Infrastructure Program through the National Research Foundation of Korea (NRF) funded by the Korea government(MSIT)(2019K1A3A1A18116048)(WonHyoung Ryu), the NRF grant funded by the Korea government(MSIT)(2020R1A2C3013158)(WonHyoung Ryu), the Yonsei-KIST Convergence Research Program(WonHyoung Ryu), and a grant of NRF grant funded by the Korean government(MSIT)(2021R1F1A105502211)(KangJu Lee).