Rapid duplexed detection of illicit drugs in wastewater using gold nanoparticle conjugated aptamer sensors

Abstract

The abuse of illicit drug addiction is a worldwide public health and social problem. In this paper, we reported on a simple and rapid colorimetric biosensor for duplexed detection of methamphetamine (METH) and cocaine in a single assay. Gold nanoparticles (AuNPs) and Au@Ag NPs were synthesized and functionalized with DNA reporter probes (RPs) for METH and cocaine, respectively. The magnetic beads (MBs) were conjugated with two capture probes (CPs) respective to METH and cocaine. The respective RPs and CPs were designed to hybridize with each illicit drug-binding DNA aptamers through DNA-DNA hybridization, forming a sandwich structure. This MBs-based sandwich structure could be removed with an external magnetic field. However, due to the higher affinity of DNA aptamers with illicit drugs, the sandwich structure was disassembled when illicit drugs are introduced into the solution, leading to the colour changes of the supernatant. Utilizing a non-negative matrix factorization (NMF) algorithm to process the data, we demonstrated the ability

Rapid, multianalyte detection of opioid metabolites in wastewater

“…Interestingly, we find a K D of 94 pM which is much better than the conventional fluorescent and HPLC techniques yet comparable to G-FET based biosensors used for other types of biomarkers. 19,23,26,47 From the fits we found the LOD was approximately 10 pM which is nearly two orders of magnitude higher than that obtained with fluorescent assay and mass spectrometry 19,48 and is comparable to that obtained for oxycodone utilizing electrodes modified with different complex nanostructures and immobilization process. 26,27 To confirm the specificity, we tested the NX-aptamers functionalized G-FET with 100 nM EDDP, only a small shift of 8 mV was seen which is much lower than that (∼60 mV) obtained with 10 pM of NX concentration (see Figure 3d).…”

“…These obtained values of K D and LOD are 2 to 3 orders of magnitude lower than those reported in the literature for all three drug metabolites. 1,12,15,19,23 Considering the 1:20 dilutions of used wastewater, these obtained LOD values are still on the order of 100 pg/ml with the detection range of pg/ml to ng/ml which is in line with the concentration range of metabolites present in wastewater. 10,11,24,25…”

“…Briefly, citrate-reduced gold nanoparticles (AuNP) possess negative charge and the electrostatic repulsive forces account for their characteristic red color when dispersed in a medium. 15,23 In the presence of a negatively charged aptamer and ∼30 mM NaCl, a negative charge cloud protects AuNPs from any aggregation (Figure 2a). When an aptamer binds to the target, it leaves the particle surface, reducing the inter-particle distance.…”

“…16,22 For example, a gold nanoparticles conjugated assay was reported with a LOD of 0.5 nM (0.15 ng/ml) and 3.3 nM (1 ng/ml) for Methadone and Cocaine respectively. 23 The optical assays-based techniques using nanomaterials are limited by high LOD, miniaturization, complex equipment, and cost. On the other hand, the LFIA and electrochemical sensors have the capability to solve several challenges, but have yet to achieve high sensitivity and stability in real wastewater samples.…”

Chemical sensing with Au and Ag nanoparticles

“…Mao and co-workers developed a strategy to detect methamphetamine and cocaine through a non-aggregated Au@Ag core@shell NPs methodology. (276,277) For this purpose they have employed a three component system: I) An aptamer which is specific for cocaine or methamphetamine II) Au@Ag NPs stabilized with a DNA sequence partially complementary to the aptamer, and III) magnetic beads conjugated with another DNA sequence partially complementary to the aptamer sequence. The NPs assembly is triggered by the mixture of the three components through a DNA-DNA hybridization, forming a sandwich structure.…”