Rapid, multianalyte detection of opioid metabolites in wastewater

Abstract

By monitoring opioid metabolites, wastewater-based epidemiology (WBE) could be an excellent tool for real-time information on consumption of illicit drugs. A key limitation of WBE is the reliance on costly laboratory-based techniques that require substantial infrastructure and trained personnel, resulting in long turnaround times. Here, we present an aptamer-based graphene field effect transistor (AptG-FET) platform for simultaneous detection of three different opioid metabolites. This platform provides a reliable, rapid, and inexpensive method for quantitative analysis of opioid metabolites in wastewater (WW). The platform delivers a limit of detection (LOD) 2-3 orders of magnitude lower than previous reports, but in line with the concentrations range (pg/ml to ng/ml) of these opioid metabolites present in real samples. To enable multianalyte detection we developed a facile, reproducible, and high yield fabrication process producing twenty G-FETs with integrated side gate platinum (Pt) electrodes on a single chip. Our devices achieved the simultaneous and selective multianalyte detection of three different metabolites: Noroxycodone (NX), 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), and Norfentanyl (NF) in wastewater.

Epitaxial Atomic Substitution for MoS2–MoN Heterostructure Synthesis

“…As shown in Figure 5a, a 30-nm thick Al 2 O 3 film as a mask is deposited on the patterned region of a three-layered exfoliated MoS 2 flake via e-beam evaporation. 68,69 The sample is then heated up to 720 °C under the ammonia atmosphere. The optical image after 60 min of reaction (Figure 5b) clearly shows that the exposed area of MoS 2 undergoes the conversion process and the optical contrast changes, while the Al 2 O 3 -protected region retains the same optical contrast.…”

“…Future studies on interlayer coupling between MoS 2 and MoN and the properties of the moirésuperlattice are needed to provide deeper understanding of the high-contrast moirépattern in large area.Taking advantage of the high conductivity of MoN which can be utilized as desired electrode materials for semiconducting MoS 2 FETs,47,48 we further apply a mask-assisted conversion method to fabricate the atomically bonded MoS 2 − MoN lateral heterostructures with a designed pattern for the study of electrical properties. As shown in Figure5a, a 30-nm thick Al 2 O 3 film as a mask is deposited on the patterned region of a three-layered exfoliated MoS 2 flake via e-beam evaporation.68,69 The sample is then heated up to 720 °C under the ammonia atmosphere. The optical image after 60 min of reaction (Figure5b) clearly shows that the exposed area of MoS 2 undergoes the conversion process and the optical contrast changes, while the Al 2 O 3 -protected region retains the same optical contrast.…”