Early diagnosis of melanoma through in situ monitoring using a microneedle colorimetric device

Cutaneous melanoma, characterized by high recurrence, metastasis, and mortality rates, necessitates early diagnosis to improve patient survival. Current methods for melanoma screening, primarily dermoscopy and skin biopsies, face critical limitations: dermoscopy often sacrifices sensitivity, while biopsy requires invasive tissue removal, compromising patient compliance. Here, we present a minimally invasive microneedle-based device for early melanoma detection through interstitial fluid (ISF) analysis. The device consists of a vacuum extraction system for ISF extraction, a fluid reservoir for storing chromogenic solution, and a lyophilized gelatin hydrogel for lactate dehydrogenase sensing. The detection capability of the device is validated both in vitro and in vivo in a melanoma-bearing mice model. The device successfully distinguishes melanoma-bearing mice from healthy controls at early stage, without influencing tumor progression. This minimally invasive and visually readable device offers a patient-friendly alternative to traditional invasive procedures for melanoma screening.