Microneedle-Integrated Sensors for Extraction of Skin Interstitial Fluid and Metabolic Analysis

Abstract

Skin interstitial fluid (ISF) has emerged as a fungible biofluid sample for blood serum and plasma for disease diagnosis and therapy. The sampling of skin ISF is highly desirable considering its easy accessibility, no damage to blood vessels, and reduced risk of infection. Particularly, skin ISF can be sampled using microneedle (MN)-based platforms in the skin tissues, which exhibit multiple advantages including minimal invasion of the skin tissues, less pain, ease of carrying, capacity for continuous monitoring, etc. In this review, we focus on the current development of microneedle-integrated transdermal sensors for collecting ISF and detecting specific disease biomarkers. Firstly, we discussed and classified microneedles according to their structural design, including solid MNs, hollow MNs, porous MNs, and coated MNs. Subsequently, we elaborate on the construction of MN-integrated sensors for metabolic analysis with highlights on the electrochemical, fluorescent, chemical chromogenic, immunodiagnostic, and molecular diagnostic MN-integrated sensors. Finally, we discuss the current challenges and future direction for developing MN-based platforms for ISF extraction and sensing applications.

Review—Smart Wearable Sensors for Health and Lifestyle Monitoring: Commercial and Emerging Solutions

“…Current microneedle wearables can be classified into solid, hollow, porous, and coated categories, each with various advances and drawbacks. 82 Despite their inherent complex design, microneedle wearable sensors have been recently applied as powerful wearable sensor platforms to detect clinically significant substances and monitor biomarkers or ingested medicines. 83,84 Integrating advanced biosensors into wearables presents a promising avenue for the future of smart wearable sensors, whose capabilities extend beyond simple "sensing.…”

Harvesting and manipulating sweat and interstitial fluid in microfluidic devices

“…Solid microneedles will extract more with higher vacuum pull and lower capillary diameter, while porous, soft microneedles will hold more ISF than their solid counterparts. 82 Sweat and ISF transport and management are needed next for prolonged sensing and sampling. Hence, the next section highlights ways of sweat management in microfluidic channels.…”

Developing Porous Microneedles Patch for the Detection of Wound Infections

“…[17,18] MNs platforms designed for diagnosis can extract medically relevant biomarkers within body fluids and secretions, including IFS, saliva, urine, tears, sweat and so on. [19,20] A microfluidic detection platform, comprising a porous structure and MNs patches, facilitates the analysis of wound infection markers. [21] Microneedle (MN) patch comprises a back substrate with an array of micron-sized needles.…”