Quantitative and rapid detection of morphine and hydromorphone at the point of care by an automated giant magnetoresistive nanosensor platform.

Opioids, such as morphine and hydromorphone, are common pain management drugs with a high risk for addiction and adverse effects when delivered in large doses or administered too frequently. Point-of-care (POC) tools provide a solution to combat these negative outcomes through active monitoring of opioid concentrations in clinical settings. We demonstrate that giant magnetoresistive (GMR) nanosensors offer a quantitative, sensitive, and rapid solution for low-cost, sample-to-answer opioid detection at the POC. We show the robust nature of GMR nanosensors by developing a competitive morphine assay and characterizing it in saliva, blood, and plasma. We then implemented the assay on a fully automated POC GMR platform and demonstrated its duality to detect either morphine or hydromorphone using only 180 μL of direct saliva without the need for pre-processing. In 35 min from sample addition to result, the automated platform was controlled via smartphone and had seamless transmission of results via Bluetooth. The fully automated POC assay had a limit of detection of 3.43 ng/mL for morphine and 3.49 ng/mL for hydromorphone. The low-cost, 80-plex GMR nanosensor array coupled with the automated POC platform enables future development of multiplexed drug screening tools that can be deployed in clinical settings using a wide variety of non-invasive matrices.