LiFT (a Lithium Fiber‐based Test): An At‐home Companion Diagnostics for a Safer Lithium Therapy in Bipolar Disorder

AbstractFor the past 70 years, lithium has been used as a mood stabilizer for the treatment of bipolar disorder. The toxicity of lithium and its narrow therapeutic window has been known for decades. Close monitoring of lithium concentration in biofluids and adjustment of drug dosage can minimize the devastating side effects, such as permanent kidney and neurological damage. Despite this, we still do not have point‐of‐care tools that can accurately measure lithium levels in biofluids for frequent monitoring. This work presents LiFT (a lithium fiber‐based test), the first low‐cost electrochemical sensor that can measure lithium in human saliva and urine with FDA‐required accuracy. LiFT revolutionizes the management of lithium therapy by providing an inexpensive yet accurate and simple‐to‐operate lithium sensor for frequent at‐home testing for early identification of lithium toxicity and rapid intervention. The low cost and high accuracy of LiFT were enabled through an innovative design and the use of ubiquitous materials such as yarn and carbon black for fabrication. LiFT measures Li+ through potentiometric recognition using a lithium selective sensing membrane that is deposited on the ink‐coated yarn. we obtained a detection limit of 0.97 M with a sensitivity of 59.07±1.25 mV/decade for the Li+ sensor in deionized water. Moreover, our sodium correction extended LiFT's linear range in urine and saliva to 0.5 mM. our LiFT platform sends the test results to the patient's smartphone, which subsequently could be shared with the patient's healthcare provider to expedite diagnosis and prevention of acute lithium toxicity.This article is protected by copyright. All rights reserved