Researchers from Boston College, Boston University, and Giner Labs have developed a groundbreaking penny-sized biosensor using atom-thick graphene. This innovative device, described in ACS Nano, is the first to utilize graphene-based field effect transistors for detecting four different opioids simultaneously in wastewater, addressing a key challenge in understanding opioid usage within communities. When an opioid metabolite binds to a molecular probe on the graphene, it alters the graphene’s electrical charge, allowing for easy electronic readings. This technology supports wastewater-based epidemiology, enabling cost-effective and highly localized measurements of opioid use. The device, funded by various organizations including the NIH, presents a faster, more affordable tool for public health officials to assess opioid consumption’s extent and the effectiveness of community-wide interventions. Furthermore, it can help provide insight into trends in the composition of the more toxic drugs trafficked on the street giving public health officials an earlier opportunity for intervention.