Project Description:

Arginine Vasopressin Deficiency (AVP-D) is a rare endocrine disorder affecting 1 in 25,000 people worldwide. Caused by insufficient antidiuretic hormone (ADH) production, AVP-D disrupts the body’s ability to regulate water balance, resulting in extreme thirst, excessive urination, sometimes up to 20 liters per day, and dangerous fluctuations in blood sodium levels. If left unmonitored, these sodium swings can lead to dehydration, seizures, and even brain damage. Currently, the only accurate sodium monitoring tools are hospital-grade systems like the Abbott i-STAT, which cost $8,000–$10,000 and are inaccessible for daily use at home. Available alternatives, like lab tests and urine dipsticks, are slow or inaccurate, leaving patients without a reliable way to manage their condition.

To address this gap, our team developed a novel, affordable, and user-friendly continuous sodium monitoring patch designed for real-time, at-home use. The patch uses an ion-selective electrode system embedded in a wearable sensor to measure sodium levels in interstitial fluid, transmitting data to a smartphone via Bluetooth for real-time tracking and alerts.

During development, we tested both a “looks-like” and “works-like” prototype to validate core design inputs. Portability was assessed by measuring the patch’s physical size and weight, ensuring it met target constraints of less than 95mm x 55mm x 25mm and under 58 grams for comfortable, continuous wear. Functionality and accuracy were tested using the “works-like” prototype: the circuit and Arduino code were evaluated with varying input voltage differences, successfully producing accurate sodium concentration outputs.

Through these engineering and user-focused design efforts, the proposed device shows strong potential to improve quality of life for AVP-D patients. Future development aims to integrate app-based data tracking and physician alerts, empowering patients to prevent dangerous sodium level swings from home and closing the gap in chronic disease self-management.