Transdermal electroosmotic flow generated by a porous microneedle array patch

Abstract

A microneedle array is an attractive option for a minimally invasive means to break through the skin barrier for efficient transdermal drug delivery. Here, we report the applications of solid polymer-based ion-conductive porous microneedles (PMN) containing interconnected micropores for improving iontophoresis, which is a technique of enhancing transdermal molecular transport by a direct current through the skin. The PMN modified with a charged hydrogel brings three innovative advantages in iontophoresis at once: (1) lowering the transdermal resistance by low-invasive puncture of the highly resistive stratum corneum, (2) transporting of larger molecules through the interconnected micropores, and (3) generating electroosmotic flow (EOF). In particular, the PMN-generated EOF greatly enhances the transdermal molecular penetration or extraction, similarly to the flow induced by external pressure. The enhanced efficiencies of the EOF-assisted delivery of a model drug (dextran) and of the extraction of glucose are demonstrated using a pig skin sample. Furthermore, the powering of the PMN-based transdermal EOF system by a built-in enzymatic biobattery (fructose / O2 battery) is also demonstrated as a possible totally organic iontophoresis patch.

Self‐Powered Controllable Transdermal Drug Delivery System

“…2) The integrated microneedle patch was more convenient to operate and fix. 3) With the MN structure, the counter electrode could pierce the highly resistive stratum corneum, resulting in significantly reduce the transdermal resistance, [ 14 ] which is more conducive to release drugs by electrical stimulation. MNP can achieve drug loading and release due to its reversible redox properties of PPy film (Figure 1c).…”

“…[ 13 ] However, the common MNs are difficult to meet on‐demand drug delivery requirement of patients, so it is necessary to develop a smart transdermal drug delivery system for controlling drug release. [ 14,15 ] As an intelligent electro‐responsive material, Polypyrrole (PPy) has the superior capability to load and release drugs by switching the oxidative and reductive state. It can be used to incorporate and release anionic, [ 16–18 ] cationic, [ 19 ] and neutral drugs.…”

Finger-Actuated Microneedle Array for Sampling Body Fluids

“…With different geometries and designs [3,4], such as solid, hollow, coated, or biodegradable [5] needle types in the scale of micrometers and nanometers [6], microneedle arrays (MNAs) can be fabricated with numerous methods such as 3D printing [7,8]. MNAs can be inserted into a target area, even within the depth of skin epidermis and thus they have emerging biomedical applications in drug delivery systems [9][10][11][12] with the capability of programmed deliveries of drug doses for multiple-injection therapies such as vaccination [13], sampling interstitial fluid (ISF) [14,15] biomarker detection [16], enhanced wound healing [17], fertility control [18], point-of-care (POC) setups and diagnostic tests [19,20], DNA extraction [21,22], cancer therapy [23], and force sensing [24].…”

Biodegradable Porous Microneedles for an Electric Skin Patch

“…[20][21][22][23][24] A charge-immobilized PMN has recently been demonstrated to generate electroosmotic flow (EOF) that can accelerate transdermal penetration of molecules and the extraction of ISF. [25] A practical PMN would be ideally made of biodegradable materials such as poly(lactic-co-glycolic acid) (PLGA) to ensure the safety even if it breaks within the skin, while most have been prepared from metals, ceramics, or conventional plastics. Recently, Kim et al fabricated a PMN of PLGA using a salt-leaching method and applied it to the sampling of artificial ISF.…”