Where Microneedle Meets Biomarkers: Futuristic Application for Diagnosing and Monitoring Localized External Organ Diseases (Adv. Healthcare Mater. 5/2023)

Dermal-fluid-enabled detection platforms for non-invasive ambulatory monitoring

“…Facile and less invasive ISF sampling techniques employing micro-needle arrays have been attracting interest among researchers in this domain. 10,34 This review emphasizes the potential of sweat and ISF enabled sensing platforms to complement conventional invasive blood tests to facilitate disease management in ambulatory settings (Fig. 1).…”

“…Hence, the composition of ISF is very similar to that of blood and reflective of localized physiological information. 10,109 Understanding the role of capillary structure in the partitioning of analytes in ISF from blood is vital to gaining insight into relative concentrations of biomarkers of interest.…”

“…However, it is unsuitable for ambulatory care as the biomarker composition in sampled ISF is often 5-10 times less than the physiological one. 10,32 Extraction of ISF using implantable subcutaneous sensors is widely adopted in CGM systems, but they can be invasive and cause pain, infection, and scarring. 137 The above-mentioned techniques require long sampling times, expert training, healing time for injuries, and local anesthesia.…”

“…MN arrays can be solid, hollow, porous, dissolving, and hydrogel-based. Some of the literature provides a very detailed account of these technologies 10,139 Solid and dissolving MN are mainly for single-time use as they require additional accessories for the collection and analysis of ISF. 140 Porous, hollow, and hydrogel-based integrated MN arrays have been exploited relatively more for continuous biomarker detection with simultaneous extraction and detection.…”

“…9 The most utilized biomarker sources for testing are blood and urine, which are simple to collect for laboratory analysis and can provide a snapshot of systemic biomarker changes. 10 The gold standard for diagnostics is monitoring biomarkers in blood, but the requirement for qualified healthcare workers to draw venous blood or the patient's anxiety during finger-prick blood sampling makes it unsuitable and invasive. Biofluids such as urine, tears, saliva, sweat, and interstitial fluid (ISF) are less invasive alternatives.…”