Editors' Choice—Review—In Vivo and In Vitro Microneedle Based Enzymatic and Non-Enzymatic Continuous Glucose Monitoring Biosensors

Abstract

Microneedles have emerged for transdermal monitoring of biomarkers, which are a miniaturized replica of hypodermic needles with length-scales of hundreds of micrometers, with a goal to achieve time-sensitive clinical information for routine point-of-care health monitoring. Transdermal biosensing via microneedles offers remarkable opportunities for moving biosensing technologies from research laboratories to real-field applications and enables development of easy-to-use point-of-care microdevices, minimally invasive, and with minimal-training features that are very attractive for both developed and emerging countries. This would eliminate the need for blood extraction using hypodermic needles and in turn, reduce the related problems such as infections in the patients, sample contaminations, and analysis artifacts. In this review, we provide a general overview of recent progress in microneedlebased sensing research, including: (a) in-vivo microneedle diagnostic systems for glucose monitoring with an emphasis on sensor construction and general health monitoring (b) in-vitro use of microneedle sensors. The main objective of the review is to provide a thorough and critical analysis of recent advances and developments in microneedle research field and to bridge the gap between microneedles and biosensors.

Microneedle-based bioassays

“…90 Another application of electrochemistry-based MN devices is continuous glucose monitoring, which could greatly help improve diabetes management. 91,92 Bollella et al developed a porous gold MNbased biosensor for minimally invasive monitoring of glucose. The MN electrode was prepared by gold electrodeposition, and the porous gold surface was immobilized with 6-(ferrocenyl) hexanethiol (a redox mediator) and avin adenine dinucleotide glucose dehydrogenase.…”

Minimally Invasive Glucose Monitoring Using a Highly Porous Gold Microneedles-Based Biosensor: Characterization and Application in Artificial Interstitial Fluid

“…They are based on glucose oxidase (GOx) and continuously measure glucose levels in the interstitial fluid (ISF) using a needle that penetrates into the subcutaneous tissue. Glucose concentrations in capillary bloods are the same as in the ISF with a mean lag time of 6-7 min [7][8][9]. CGM devices offer the advantage of being wearable biosensors that send data wirelessly to a display device through a transmitter.…”

“…Despite their advantages, these devices are still invasive and associated with some discomfort. Moreover, they show biofouling effects due to surface deposition of proteins and cells [7].…”

Improving Linear Range Limitation of Non-Enzymatic Glucose Sensor by OH− Concentration

“…Although the result of enzymatic test-strips is accurate; they have many limitations, the most critical of which is their requirement on humidity and temperature [4][5][6][7]. This is caused by the presence of enzyme, which inspired the researchers to focus on non-enzymatic glucose sensing, due to the advantage of easy operation, fast response and low cost [8][9][10][11].…”