Concept Design of Transdermal Microneedles for Diagnosis and Drug Delivery: A Review

Abstract

Microneedles (MNs) are one of intriguing approach for efficient transdermal drug delivery that penetrates the protective skin barrier in a painless and less invasive way. In recent years, multidisciplinary studies have been conducted to improve their properties to meet stringent requirements and obtain market release approval. This review aims to summarize the latest concept design with unique properties in the advancement of transdermal MNs for diagnosis and therapeutic application. Numerous significant innovation strategies in improving MNs in aspects of adhesion ability, dosing capacity, drug‐controlled release, diffusion control ability, site‐targeted and on‐demand drug delivery, and biomarker or drug release monitoring are presented. Given that the majority of technologies used in such design are exclusively laboratory‐based, striving toward commercialization is a critical aspect of the revolution. Key challenges and future perspectives in industrial and economic aspects are identified with the intention of translating the reviewed technologies into marketable products.

Advances in the noninvasive and minimally invasive sample collection for wearable electrochemical sensors

“…As far as we know, most microneedle-based wearable biochemical sensors utilize electrochemical techniques due to their high adaptation to the microneedle platforms [48]. There are mainly two operating modes for these wearable sensors: 1) the tissue fluid or blood containing biomarkers are extracted out of the human body through the bare microneedles in the absence of the recognition element for subsequent testing; 2) the microneedles are modified with the specific materials to be applied as the sensing electrodes toward the biomarkers for in situ detection [58,59]. Both two modes are of great significance and have exhibited superior performances in the developed wearable sensors.…”

Finger-Actuated Micropump of Constant Flow Rate without Backflow

“…Microneedles (MNs) are a minimally invasive method that can be used to gain access to ISF under the skin with minimal discomfort and physical damage and a low risk of infection [60][61][62][63]. Even though it is known that ISF has useful biomarkers, the extraction process is tedious, which reduces its acceptance in clinical and diagnostic settings.…”

Flexible Monitoring, Diagnosis, and Therapy by Microneedles with Versatile Materials and Devices toward Multifunction Scope

“…MNs are semi-implantable with base on surface and needle tips under skin, which can realize monitoring and regulation of both body surface and internal environment, not only for drug delivery, electrophysiological recording, real-time monitoring, and diagnosis but also for regulation of intracellular activities [ 212 ]. Semi-implantable MNs can meet the growing technical demand for accurate detection or regulation of biological activities and also provide an ideal platform for external integration of complex functions and electronic integration [ 213 ]. Although less defined and summarized than the critically acclaimed noninvasive and fully implantable bioelectronics, semi-implantable MNs has emerged as a highly unique technology driving the development of biochips and smart wearable devices.…”