Rapidly Separable Micropillar Integrated Dissolving Microneedles

Abstract

Dissolving microneedle (DMN) patches were developed as efficient and patient-friendly transdermal delivery systems for biopharmaceuticals. However, recent studies have confirmed that the efficiency of DMNs to deliver biopharmaceuticals is highly reduced because of incomplete insertion caused by the stiffness and elastic properties of the skin. Therefore, micropillar integrated DMNs were developed to overcome the insertion limitations of DMN patches. Although micropillars were designed as integrated applicators to implant DMNs across the skin, they can also become inserted into the skin, leading to skin injury and inflammation. Herein, we have developed a separable micropillar integrated DMN (SPDMN) capable of inserting DMNs across the skin with high efficiency while minimizing skin injury risk through the introduction of a safety ring feature. Unlike previously developed systems, the SPDMN does not require continuous skin attachment and can be detached immediately post-application, leaving DMNs implanted inside the skin. Altogether, the findings of this study lead to the development of a quick, safe, and efficient DMN-based drug delivery platform.

Separable Microneedle Patch to Protect and Deliver DNA Nanovaccines Against COVID-19

“… 32 Other studies have applied dissolvable polymer as the backing layer to separate from the microneedles. 33 The backing layer can be efficiently detached from the microneedles using those methods, but the separation is not controllable. The separation process would start immediately once the patch is pushed into skin.…”

“…After inserting into the skin, the blunt metal shafts can be separated from the microneedles and left in the skin . Other studies have applied dissolvable polymer as the backing layer to separate from the microneedles . The backing layer can be efficiently detached from the microneedles using those methods, but the separation is not controllable.…”

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

“…The hydrogel particles immediately absorbed water, causing the microneedles to break owing to the differential volume expansion between the needle–matrix polymer and the hydrogel particles [ 253 , 282 , 283 ]. The enlarged particles completely disintegrated the microneedles, leaving the microneedle tips in the skin of a porcine cadaver in vitro and a hairless mouse in vivo [ 284 , 285 , 286 ]. Figure 6 shows the fabrication of dissolving microneedle arrays with the PDMS micromolding technique.…”

“…In the viable epidermis and dermis, many antigen-presenting cells (APCs) such as Langerhans cells (LCs) and dermal dendritic cells may be detected (dDCs) [ 254 , 303 , 304 ]. Antigen-presenting cells gather antigens and subsequently transport them to draining lymph nodes, where they transfer the antigen to T cells, activating Ag-specific T cells and B cells for a systemic immune response [ 41 , 220 , 286 ]. Microneedles penetrate the skin barrier and underneath tissue to transfer the antigen into the epidermis or dermis while staying short enough to avoid pain receptors, therefore preventing pain sensation [ 261 , 305 ].…”

Film-trigger applicator (FTA) for improved skin penetration of microneedle using punching force of carboxymethyl cellulose film acting as a microneedle applicator

“…To overcome the limitation of insertion of microneedle patch, researchers have developed various applicators to enhance insertion of DMN patches [18][19][20]. Generally, a patch applicator consists of an even plate to press the patch and external power source to provide a sufficient force to the plate [21].…”