Tissue Interlocking Dissolving Microneedles for Accurate and Efficient Transdermal Delivery of Biomolecules

Abstract

The interest in safe and efficient transdermal drug delivery systems has been increasing in recent decades. In light of that, polymeric dissolving microneedles (DMNs) were developed as an ideal platform capable of delivering micro- and macro-biomolecules across the skin in a minimally invasive manner. A vast majority of studies, however, suggest that the shape of DMNs, as well as the elastic properties of skin, affects the delivery efficiency of materials encapsulated within DMNs. Likewise, in dynamic tissues, DMNs would easily distend from the skin, leading to inefficient delivery of encapsulated agents. Thus, herein, to improve delivery efficiency of DMN encapsulated agents, a novel hyaluronic acid backbone-based tissue interlocking DMN (TI-DMN) is developed. TI-DMN is simple to fabricate and significantly improves the transdermal delivery efficiency of encapsulated materials compared with traditional DMNs. The enhanced tissue interlocking feature of TI-DMN is achieved through its sharp tip, wide body, and narrow neck geometry. This paper demonstrates that TI-DMN would serve as an attractive transdermal delivery platform to enhance penetration and delivery efficiency of a wide range of biomolecules into the body.

Micro-Pillar Integrated Dissolving Microneedles for Enhanced Transdermal Drug Delivery

“…Drug-encapsulated DMNs are generally fabricated in arrays onto sticky patches and applied onto the skin for minutes to hours, depending on the type and viscosity of their backbone matrix materials [22,23,24,25]. Fabricating DMNs over patches, however, was shown to affect delivery accuracy and reduce the efficiency of the encapsulated drugs, due to the incomplete penetration of DMNs into the skin [26,27]. The vast majority of studies showed that because of the physico-chemical properties of the skin, DMNs are not completely inserted into it, resulting in a random and inconsistent release of encapsulated compounds with each application [28,29].…”

Scalp Micro-Pigmentation via Transcutaneous Implantation of Flexible Tissue Interlocking Biodegradable Microneedles

“…Centrifugation of the secondary droplet created a double-layered PBM with a narrow neck, a wide mid-portion, and a sharp tip (Figure 1a). PBMs, because of their morphology, are capable of achieving a precise implantation of micro-pigments without utilizing an applicator [28]. Thus, individuals can use finger force to apply PBMs to the targeted scalp region and achieve a highly accurate implantation (Figure 1b).…”

“…PBMs comprise a micro-dimensioned polymeric transdermal system designed to implant the encapsulated micro-pigments in a minimally invasive manner [25,26,27]. A recently developed fabrication technique that produces a “tissue interlocking dissolving microneedle”, capable of the accurate delivery of encapsulated materials, is employed to achieve a precise implantation of micro-pigments below the epidermis [28]. PBMs comprise an unpigmented base layer, acting as a shaft to implant micro-pigments beneath the epidermis, and a micro-pigment encapsulating top layer.…”

Advances in the Formulations of Microneedles for Manifold Biomedical Applications

“…A further development of DAB is the centrifugal lithography (CL),8b in which the droplets are shaped and solidified into MN by centrifugal force under vacuum condition. A wide range of needle geometry (i.e., sharp needle, swollen body, narrow base) can be made through the CL method . For example, a wine glass‐shaped primary layer was constructed with a primary wine glass‐shaped layer and a sharp tip secondary layer.…”