Monitoring genetic population biomarkers for wastewater-based epidemiology

We report a rapid “sample-to-answer” platform that can be used for the quantitative monitoring of genetic biomarkers within communities through the analysis of wastewater. The assay is based on the loop-mediated isothermal amplification (LAMP) of nucleic acid biomarkers and shows for the first time the ability to rapidly quantify human-specific mitochondrial DNA (mtDNA) from raw untreated wastewater samples. mtDNA provides a model population biomarker associated with carcinogenesis including breast, renal and gastric cancers. To enable a sample-to-answer, field-based technology, we integrated a filter to remove solid impurities and perform DNA extraction and enrichment into a low cost lateral flow-based test. We demonstrated mtDNA detection over seven consecutive days, achieving a limit of detection of 40 copies of human genomic DNA per reaction volume. The assay can be performed at the site of sample collection, with minimal user intervention, yielding results within 45 min and providing a method to monitor public health from wastewater

A novel colorimetric biosensor based on non-aggregated Au@Ag core–shell nanoparticles for methamphetamine and cocaine detection

We report a novel colorimetric biosensor based on non-aggregation Au@Ag core-shell nanoparticles to detect methamphetamine and cocaine. The biosensor consisted of a reporter probe (RP) that is a specific single-stranded DNA (ssDNA) sequence coated on Au@Ag nanoparticles, a capture probe (CP) conjugated with magnetic beads, and an illicit drug-binding DNA aptamer (Apt). Au@Ag nanoparticles were synthesized by seed growth and characterized by scanning electron microscope (SEM), high-resolution transmission electron microscopy (HR-TEM), and UV–vis spectra. Methamphetamine (METH) was used as an example to evaluate the feasibility of the biosensor and to optimize the detection conditions. We demonstrated that this sensing platform was able to detect as low as 0.1 nM (14.9 ng L−1) METH with a negligible interference from other common illicit drugs. Various concentrations of METH were spiked into urines, and the biosensor yielded recoveries more than 83.1%. In addition, the biosensor also showed a high sensitivity to detect cocaine. These results demonstrated that our colorimetric sensor holds promise to be implemented as a visual sensing platform to detect multiple illicit drugs in biological samples and environmental matrices

Community sewage sensors towards evaluation of drug use trends: detection of cocaine in wastewater with DNA-directed immobilization aptamer sensors

Illicit drug use has a global concern and effective monitoring and interventions are highly required to combat drug abuse. Wastewater-based epidemiology (WBE) is an innovative and cost-effective approach to evaluate community-wide drug use trends, compared to traditional population surveys. Here we report for the first time, a novel quantitative community sewage sensor (namely DNA-directed immobilization of aptamer sensors, DDIAS) for rapid and cost-effective estimation of cocaine use trends via WBE. Thiolated single-stranded DNA (ssDNA) probe was hybridized with aptamer ssDNA in solution, followed by co-immobilization with 6-mercapto-hexane onto the gold electrodes to control the surface density to effectively bind with cocaine. DDIAS was optimized to detect cocaine at as low as 10 nM with a dynamic range from 10 nM to 5 μM, which were further employed for the quantification of cocaine in wastewater samples collected from a wastewater treatment plant in seven consecutive days. The concentration pattern of the sampling week is comparable with that from mass spectrometry. Our results demonstrate that the developed DDIAS can be used as community sewage sensors for rapid and cost-effective evaluation of drug use trends, and potentially implemented as a powerful tool for on-site and real-time monitoring of wastewater by un-skilled personnel

Cancer biomarkers detection using microstructured protein chip: implementation of customized multiplex immunoassay

Protein chips have demonstrated to be a sensitive and low cost solution to identify and detect tumor markers. However, efficient multiparametric analysis remains a challenge due to protein variability. Crucial parameters are the design of stable and reproducible surfaces which maintain biological activity of immobilized proteins, and immobilization conditions (buffer, pH, concentration). We have developed and characterized various surface chemistries for the immobilization of anti-tumor antigen antibodies onto microstructured glass slides. The effect of surface properties and antibody immobilization conditions was evaluated on the detection of tumor antigens involved in colorectal cancer. Experimental results demonstrated that each antibody displays variable biological activities depending on the surface chemistry and on the immobilization procedure. Under optimized conditions, we can reach a limit of detection in tumor antigen as low as 10 pM. Our microstructured chip offers the possibility to implement a customized multiplex immunoassay combining optimal immobilization condition for each antibody on the same chip

Blue-emitting SiO₂-coated Si-doped ZnSeS quantum dots conjugated aptamer-molecular beacon as an electrochemical and metal-enhanced fluorescence biosensor for SARS-CoV-2 spike protein

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which was first reported in early January 2020, continues to devastate the worlds public health system. Herein, we report on the development of a novel metal-enhanced fluorescence (MEF) and electrochemical biosensor for SARS-CoV-2 spike (S) protein. To develop the MEF biosensor, SiO2-coated Si-doped ZnSeS quantum dots (QDs) were newly synthesized and conjugated to an aptamer-molecular beacon (Apta-MB) probe. Thereafter, cationic AuNPs, used as a localised surface plasmon resonance (LSPR) signal amplifier, were self-assembled on the QDs-Apta-MB conjugate to form a QDs-Apta-MB-AuNP probe. To develop the electrochemical biosensor, the QDs-Apta-MB assay was carried out on a carbon nanofiber-modified screen-printed carbon electrode. Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were used to characterize the electrode surface whilst spectrophotometric, spectroscopic, fluorescence polarization and electron microscopic techniques were used to characterize the materials. Under optimal experimental conditions, the QDs binding to the Apta-MB, quenched the QDs’ fluorescence and with SARS-CoV-2 S protein binding to the Apta-MB, LSPR signal from cationic AuNPs of different sizes and shapes were used to tune the fluorescence signal to obtain enhanced sensitivity. On the other hand, using [Fe(CN)6]/K3−/4- buffered with NaAc-KAc-TrizmaAc-KSCN-Borax as the electrolyte solution, anodic peaks of the QDs from the CV and DPV plots were unravelled. Electrochemical detection of SARS-CoV-2 S protein was accomplished by a systematic increase in the QDs anodic peak current generated from the DPV plots. The limits of detection obtained for the SARS-CoV-2 S protein were 8.9 fg/mL for the QDs-Apta-MB-AuNP MEF probe and ∼0.5 pg/mL for the QDs-Apta-MB electrochemical probe. Detection of SARS-CoV-2 S protein in saliva was demonstrated using the QDs-Apta-MB-AuNP MEF probe

Graphene nanocomposites modified electrochemical aptamer sensor for rapid and highly sensitive detection of prostate specific antigen

Prostate specific antigen (PSA) is a widely used marker for the diagnosis of prostate cancer, and the increasing attention has been attracted on the development of rapid assay using biosensing technology. However, it remains challenging for the sensitive and selective detection of PSA in clinical samples. Here, we report a label-free microfluidic paper-based analytical device for highly sensitive electrochemical detection of PSA. The paper device was fabricated with wax printing to generate hydrophobic and hydrophilic layers for the construction of microfluidic channel, followed by screen-printing of three electrodes including working, counter and reference electrode. Gold nanoparticles (AuNPs)/reduced graphene oxide (rGO)/thionine (THI) nano composites were synthesized and characterized, which were coated onto working electrodes for the immobilization of DNA aptamer probe. THI servers as the electrochemical mediator to transduce the biological recognition between DNA aptamer and PSA, and the excellent conductivity of AuNPs and rGO also play a significant role of electron transfer, leading to a sensitive detection for PSA, able to detect PSA as low as 10 pg mL , with a linear range from 0.05 to 200 ng mL . We demonstrated that our electrochemical sensor for the detection of clinical serum samples, indicating that our sensor would provide a new platform for low cost, sensitive and point-of-care diagnosis of prostate cancer

The potential of an integrated biosensor system with mobile health and wastewater-based epidemiology (iBMW) for the prevention, surveillance, monitoring and intervention of the COVID-19 pandemic

The outbreak of novel coronavirus pneumonia (COVID-19) has caused a significant public health challenge worldwide. A lack of effective methods for screening potential patients, rapidly diagnosing suspected cases, and accurately monitoring the epidemic in real time to prevent the rapid spread of COVID-19 raises significant difficulties in mitigating the epidemic in many countries. As effective point-of-care diagnosis tools, simple, low-cost and rapid sensors have the potential to greatly accelerate the screening and diagnosis of suspected patients to improve their treatment and care. In particular, there is evidence that multiple pathogens have been detected in sewage, including SARS-CoV-2, providing significant opportunities for the development of advanced sensors for wastewater-based epidemiology that provide an early warning of the pandemic within the population. Sensors could be used to screen potential carriers, provide real-time monitoring and control of the epidemic, and even support targeted drug screening and delivery within the integration of emerging mobile health (mHealth) technology. In this communication, we discuss the feasibility of an integrated point-of-care biosensor system with mobile health for wastewater-based epidemiology (iBMW) for early warning of COVID-19, screening and diagnosis of potential infectors, and improving health care and public health. The iBMW will provide an effective approach to prevent, evaluate and intervene in a fast, affordable and reliable way, thus enabling real-time guidance for the government in providing effective intervention and evaluating the effectiveness of intervention

Paper-based devices for rapid diagnostics and testing sewage for early warning of COVID-19 outbreak

oronavirus disease (COVID-19), caused by SARS-CoV-2, evolved into a global pandemic in 2020, and the outbreak has taken an enormous toll on individuals, families, communities and societies around the world. One practical and effective strategy is to implement rapid case identification based on a rapid testing to respond to this public health crisis. Currently, the available technologies used for rapid diagnostics include RT-PCR, RT-LAMP, ELISA and NGS. Still, due to their different limitations, they are not well suited for rapid diagnosis in a variety of locations. Paper-based devices are alternative approaches to achieve rapid diagnosis, which are cost-effective, highly selective, sensitive, portable, and easy-to-use. In addition to individual virus screening, wastewater-based epidemiology has been emerged to be an effective way for early warning of outbreak within the population, which tests viral genome sequence to reflect information on the spread and distribution of the virus because SARS-CoV-2 can be shed into wastewater through the feces and urine from infected population. In this paper, we describe paper-based device as a low-cost and rapid sensor for both diagnosis and testing of sewage for early warning of outbreak. More importantly, the device has great potential for real-time detection in the field, without any advanced facilities or well-trained and skilled personnel, and provides early warning or timely intervention of an outbreak of pandemic

The status of potable water reuse implementation

A review of the current status of direct and indirect potable water reuse (DPR/IPR) implementation has been conducted, focusing on the regulatory and practical aspects and with reference to the most recent published literature. The review encompasses (a) the principal contaminant types, their required removal and the methods by which their concentration is monitored, (b) regulatory approaches and stipulations in assessing/ratifying treatment schemes and maintaining treated water quality, and (c) existing full-scale installations. Analytical methods discussed include established in-line monitoring tools, such as turbidity measurement, to more recent polymerase chain reaction (PCR)-based assay methods for microbial detection. The key risk assessment tools of quantitative microbial risk assessment (QMRA) and water safety plans (WSPs) are considered in relation to their use in selecting/ratifying treatment schemes, and the components of the treatment schemes from 40 existing IPR/DPR installations summarised. Five specific schemes are considered in more detail. The review reveals: 1. over half of the schemes identified employ reverse osmosis (RO) followed by UV disinfection, with UV-based advanced oxidation used in many modern schemes as the final step; 2. Whilst quantitative PCR appears to offer many advantages for microbial detection, due to its sensitivity and specificity, it nonetheless demands pre-concentration of the sample and is subject to interference leading to possible false positives; 3. QMRA studies suggest that the risk imposed by DPR and, in particular, IPR is very small compared with de facto reuse, the latter being subject to far less regulatory scrutiny; 4. There appears to be no evidence of acute conditions, and diarrhoeal disease specifically, from the few epidemiological studies which have been conducted; and. 5. IPR implementation becomes challenging if unbounded environmental waters are used as a buffer, since “zero deterioration” in environmental quality must then be demonstrated. Whilst there are a number of ongoing projects where RO is not used because of the challenge imposed by disposal of RO concentrate, the prevalence of the sequential RO-UV combination implies the importance of quantifying the impact of process upsets on these unit operations.Engineering and Physical Sciences Research Council (EPSRC): EP/P017460/1. Natural Environment Research Council (NERC): NE/R013349/2

Can a paper-based device trace COVID-19 sources with wastewater-based epidemiology?

A recent outbreak of novel coronavirus pneumonia (COVID-19) caused by SARS-CoV-2 infection has spread rapidly around the globe, with cases now confirmed in 130 countries worldwide. Although public health authorities are racing to contain the spread of COVID-19 around the world, the situation is still grim. About 158 111 confirmed cases and 5946 cumulative deaths (81 059 confirmed cases and 3204 cumulative deaths from China) have been reported around the globe as of March 15, 2020. Some clinical cases have found that some carriers of the virus may be asymptomatic, with no fever, and no, or only slight symptoms of infection. Without the ability to screen these asymptomatic patients quickly and effectively, these unsuspecting carriers have the potential to increase the risk of disease transmission if no early effective quarantine measures are implemented. Therefore, to trace unknown COVID-19 sources, fast and accurate screening of potential virus carriers and diagnosis of asymptomatic patients is a crucial step for intervention and prevention at the early stage