At‐Home Early Diagnosis of Mastitis: Calibration‐Free Analysis of Sodium to Potassium Ratio in Breast Milk

Abstract Mastitis occurs when blocked milk ducts lead to inflammation of the breast tissue and can cause significant discomfort for breastfeeding mothers. A key biomarker for mastitis is the altered sodium‐to‐potassium (Na + /K + ) ratio in breast milk due to tight junction dysfunction. In this work, MAMAWEL is introduced, the first potentiometric sensor designed for at‐home mastitis diagnosis. This device integrates Na + and K + sensors with an ionic‐liquid‐based reference electrode, enabling early detection of mastitis before clinical symptoms arise. To ensure reliable, calibration‐free operation, 2,2,6,6‐tetramethylpiperidinyloxy (TEMPO) is incorporated, a redox buffer that establishes a thermodynamically controlled interface, enhancing sensor reproducibility. Comparative analysis with commercially available sensors demonstrates that MAMAWEL effectively differentiates between healthy and mastitis‐affected milk samples, achieving a concentration estimation error margin of less than 10%. Designed for both wearable and point‐of‐care applications, MAMAWEL has the potential to transform early mastitis detection, reducing maternal discomfort and promoting breastfeeding health.