Microneedles for Transdermal Biosensing: Current Picture and Future Direction

Abstract

A novel trend is rapidly emerging in the use of microneedles, which are a miniaturized replica of hypodermic needles with length-scales of hundreds of micrometers, aimed at the transdermal biosensing of analytes of clinical interest, e.g., glucose, biomarkers, and others. Transdermal biosensing via microneedles offers remarkable opportunities for moving biosensing technologies and biochips from research laboratories to real-field applications, and envisages easy-to-use point-of-care microdevices with pain-free, minimally invasive, and minimal-training features that are very attractive for both developed and emerging countries. In addition to this, microneedles for transdermal biosensing offer a unique possibility for the development of biochips provided with end-effectors for their interaction with the biological system under investigation. Direct and efficient collection of the biological sample to be analyzed will then become feasible in situ at the same length-scale of the other biochip components by minimally trained personnel and in a minimally invasive fashion. This would eliminate the need for blood extraction using hypodermic needles and reduce, in turn, related problems, such as patient infections, sample contaminations, analysis artifacts, etc. The aim here is to provide a thorough and critical analysis of state-of-the-art developments in this novel research trend, and to bridge the gap between microneedles and biosensors.

4D Printing of a Bioinspired Microneedle Array with Backward‐Facing Barbs for Enhanced Tissue Adhesion

“…The heated solution was poured into a transparent polystyrene cube box (2.5 × 2.5 × 2.5 cm, Ted Pella, Redding, CA), and the box was cooled in a refrigerator (5 °C) for 20 min for curing. The compression modulus of the gel was 22.9 kPa, similar to typical Young's modulus of dermis layer (10–30 kPa) . A chicken muscle tissue was used as a fibrous tissue model.…”

“…The compression modulus of the gel was 22.9 kPa, similar to typical Young's modulus of dermis layer (10-30 kPa). [23] A chicken muscle tissue was used as a fibrous tissue model. The chicken was cut into specimens with 13 mm width, 15 mm length, and 11 mm thickness using a razor blade.…”

Polymeric Microneedle Arrays: Versatile Tools for an Innovative Approach to Drug Administration

“…This is what happened to the micro-and nanotechnologies that have revolutionized consumer electronics and telecommunications. [10,11] In these papers, the MNs are classified on the basis of their material (silicon, metal, glass, ceramic, polymer), shape (pyramidal, conical, solid, hollow, coated), bio-features (dissolvable, degradable, biocompatible, bioresponsive), and finally fabrication process (multistep, single step). [4] The convergence of such different fields of knowledge has generated a multitude of similar devices grouped under the single name of microneedles, which can be very different in terms of the materials used, fabrication procedures, and features exploited.…”

“…[5][6][7][8][9] Exhaustive reviews of silicon-based MN arrays and other categories of MN-based devices can be found in recent papers by Ventrelli et al and Ma et al, respectively. [10,11] In these papers, the MNs are classified on the basis of their material (silicon, metal, glass, ceramic, polymer), shape (pyramidal, conical, solid, hollow, coated), bio-features (dissolvable, degradable, biocompatible, bioresponsive), and finally fabrication process (multistep, single step). Beyond the classification of the MN patches, the working principle is always the same: the aim is to control the time and quantity of drug release and delivery through the skin without pain by tuning the physical, structural, or chemical characteristics of the device.…”

“…Ingested pills are severely degraded by the acidic environment in DOI: 10.1002/adtp.201900036 the stomach, and the efficacy of the active principle contained in the pills depends mainly on the enteric absorption. Nothing has changed in this field for more than 100 years.…”