Real-time nanomolar vitamin monitoring in sweat using an electrochemical skin-attached device

Invasive and inconvenient blood tests hinder the diagnosis and treatment of micronutrient deficiencies, which affect billions worldwide. Wearable sweat sensors offer a noninvasive and real-time alternative. However, on-body monitoring of multiple low-abundance vitamins in sweat remains challenging. Here, we show a wearable electrochemical platform that utilizes bioreceptor-functionalized gold nanoflower/sulfur and nitrogen codoped carbon to detect six low-concentration vitamins in sweat (vitamins B₁, B₂, B₇, B₉, B₁₂, and D) with nanomolar-level sensitivity. Integrated system incorporates iontophoretic sweat induction, microfluidic sampling and real-time vitamin detection with calibration. Human studies revealed temporal profiles of VB₉ levels in sweat in response to oral VB₉ supplementation and VB₉-rich diets, and a strong sweat-serum correlation (r = 0.849) has been found. The significant differences in VB₉ levels observed between smokers and nonsmokers demonstrated the potential of this technology for vitamin monitoring in diverse populations. Our platform facilitates early detection of nutritional imbalances and advances personalized nutrition.