Lab under the Skin: Microneedle Based Wearable Devices

Abstract

While the current smartwatches and cellphones can readily track mobility and vital signs, a new generation of wearable devices is rapidly developing to enable users to monitor their health parameters at the molecular level. Within this emerging class of wearables, microneedle‐based transdermal sensors are in a prime position to play a key role in synergizing the significant advantages of dermal interstitial fluid (ISF) as a rich source of clinical indicators and painless skin pricking to allow the collection of real‐time diagnostic information. While initial efforts of microneedle sensing focused on ISF extraction coupled with either on‐chip analysis or off‐chip instrumentation, the latest trend has been oriented toward assembling electrochemical biosensors on the tip of microneedles to allow direct continuous chemical measurements. In this context, significant advances have recently been made in exploiting microneedle‐based devices for real‐time monitoring of various metabolites, electrolytes, and therapeutics and toward the simultaneous multiplexed detection of key chemical markers; yet, there are several grand challenges that still exist. In this review, we outline current progress, recent trends, and new capabilities of microneedle‐empowered sensors, along with the current unmet challenges and a future roadmap toward transforming the latest innovations in the field to commercial products.

Recent Advances in Microneedle-Based Sensors for Sampling, Diagnosis and Monitoring of Chronic Diseases

“…In recent years, different types of MN-based biosensors including electrochemical, optical, magnetic, and paper-based have been studied in the literature [ 140 , 141 , 142 , 143 , 144 , 145 ]. Besides some exceptions, electrochemistry is the preferred approach in MN-based biosensor design owing to many notable properties, including inherent miniaturization, highly scalable fabrication, rapid, inexpensive, low-power consumption requirements, and easier deployment to MNs [ 36 , 146 , 147 , 148 , 149 , 150 ]. Various surface chemistry procedures and transduction modes can be combined and deployed into MN-based biosensors according to the selection of targeted biomolecule.…”

“…Recent reviews broadly focus on the use of MNs for drug delivery purposes [ 33 , 34 , 35 ]. There is a limited number of review on MN-based platforms as biosensing devices [ 29 , 36 ]. Different from other reviews, this review focuses on the state-of-the-art progresses of the MNs-based sensor systems to bridge the gaps between MNs and biosensors for the detection of CDs.…”

Finger-Actuated Microneedle Array for Sampling Body Fluids

“…Furthermore, microneedles can be integrated with biosignal acquisition techniques [7]. Therefore, MNs not only enable a minimally invasive injection experience, but they also can facilitate the development of wearable sensors [73] (with adherable MN patches) for continuous health monitoring, resulting in early diagnosis of disease, enhancing the success rate of therapies, decreasing healthcare costs, and ultimately promoting the wellbeing of the society. Hence, the acceptance and commercialization of MNs can be accelerated.…”

Microneedle Arrays for Sampling and Sensing Skin Interstitial Fluid

“…This can be considered as a paradigm shift for POC, in situ disease detection, and longitudinal monitoring [34]. Accordingly, a new research field, called "lab under the skin" has been coined that mainly refers to the applications of wearable, MN-based transdermal sensors [35].…”