A wearable device for continuous monitoring of methadone - Opioid overdose is a significant public health problem that has been escalating in recent years. Based on the statistics from the Centers for Disease Control and Prevention (CDC), the number of overdose-related deaths surpassed 100,000 from April 2020 to April 2021. This is a significant increase in overdose cases related to natural and semi-synthetic opioids, synthetic opioids, and psychostimulants. Alarmingly, in the one-year period leading up to April 2021, fentanyl was the top cause of death for adults between 18 and 45 years old, surpassing fatalities caused by car accidents, suicide, COVID, and cancer. Methadone is a well-established medication that has been used for decades to treat opioid use disorder (OUD). However, there is currently no continuous monitoring device that can provide real-time information on methadone levels in the body. This gap in monitoring can result in patients not receiving optimal doses of methadone, leading to relapse or overdose. To address this problem, we propose a wearable device for continuous monitoring of methadone. Our proposed device is a minimally invasive microneedle technology that can be worn on the skin. This device will continuously monitor methadone levels in the body, providing real-time feedback to patients and healthcare professionals. The device is small, discreet, and easy to use, making it ideal for use in various settings. The proposed SBIR project aims to leverage our innovative microneedle technology to develop a wearable device that can continuously monitor therapeutic levels of methadone in the interstitial fluid for a week. In order to achieve this, the team will perform systematic optimization studies on the surface architecture of the sensor to enable highly sensitive, stable, and selective methadone sensing performance. Aim 1 constitutes in-vitro feasibility studies to find the best chemical modification strategy with high sensitivity. Aim 2 will involve extending the stability of the sensor to one week of continuous operation. Aim 3 will assess the selectivity, reproducibility, and shelf life of the developed MN-based methadone sensors in serum samples and involves further developments in the electronics and the accompanying app of the device. Upon successful completion of Phase I, Phase II will focus on demonstrating the utility and establishing reliability of the sensor via extensive clinical studies in both animals and in human subjects. The device will not only provide accurate and personalized dosing of methadone but also help in mitigating OUD by alerting patients and healthcare professionals when levels of methadone fall below or rise above therapeutic levels. This will enable healthcare providers to adjust the methadone dose in real-time, ensuring that patients receive optimal dosages to prevent relapse and overdose. The proposed wearable device for continuous monitoring of methadone is a crucial innovation that will help to address the problem of opioid overdose. The device will provide accurate and personalized dosing of methadone, help to mitigate OUD, and can be used among different populations. Our proposed device has the potential to improve the quality of life of patients, reduce healthcare costs, and ultimately save lives.