Wireless Microneedle Patch with Integrated Electrochemical Sensor for In Situ Detection of Melanoma Biomarker Tyrosinase in ISF

Wearable microneedle biosensors have garnered significant attention for in situ analysis of biomarkers in interstitial fluid (ISF), providing a minimally invasive approach for continuous health monitoring. Nevertheless, there has been little advancement in the field of cancer diagnostics, especially in the early diagnosis of skin cancer. Here, we introduce a wearable microneedle patch with integrated Bluetooth connectivity for the transdermal detection of tyrosinase (Tyr), a key biomarker associated with melanoma. The platform integrates a highly swellable hydrogel microneedle array for efficient ISF extraction, a high-sensitivity electrochemical sensor (screen-printed carbon electrode modified with catechol) for in situ analysis, and a miniaturized Bluetooth module for wireless transmission of measured current signals. The hydrogel microneedle patch successfully extracted 8.2 μL of ISF in 4 min, and the electrochemical sensor provided quantitative Tyr detection with a sensitivity of 68.8 μA·mL·mg-1 and a low detection limit of 2.7 μg·mL-1. Furthermore, the sensor exhibited excellent selectivity against common interfering substances found in ISF. System validation using agarose gel, porcine skin (in vitro), and rat skin (ex vivo) demonstrated strong calibration linearities with R2 = 0.985, 0.981, and 0.984, respectively. Recovery rates relative to standard solutions exceeded 74.4% in vitro and 81.3% ex vivo. Consequently, this microneedle-based platform represents a promising and viable approach for the continuous, minimally invasive monitoring of cutaneous biomarkers, with the potential to enable earlier detection and more timely intervention for skin pathologies.