Zhugen Yang

Growth response of Sesbania rostrata and S. cannabina to sludge-amended lead/zinc mine tailings. A greenhouse study.

Legumes are ideal for revegetation of metal-mined wastelands which lack nitrogen (N). A greenhouse study was conducted to investigate the feasibility of using Sesbania rostrata and S. cannabina for the reclamation of lead/zinc (Pb/Zn) mine tailings and to evaluate the effects of organic amendment using sewage sludge (0%, 25%, 50%, and 75%, v/v). The results showed that both species could continue to grow on the highly toxic tailings substrata for at least 80 days, although their growth suffered from adverse effects. That S. rostrata with stem and root nodules had better growth (biomass, growth rates, and biomass of nodules) than S. cannabina suggested that S. rostrata is a better choice as a pioneer species for revegetation of the mine tailings. Stem nodules had less obvious adverse effects imposed by tailings than root nodules. Application of sewage sludge increased contents of total carbon (C), N, phosphorus (P), and potassium (K), and reduced total Zn, Pb, Cd, and DTPA-extractable Pb and Cd in tailings substrata. These, in turn, reduced metal (Zn, Pb, and Cd) uptake and accumulation in plant tissues, and improved plant growth performance, including biomass, growth rates, stem nodulation. Fifty percent (v/v) of sludge application rate was the best loading rate for plant growth.

Improvement of protein immobilization for the elaboration of tumor-associated antigen microarrays: Application to the sensitive and specific detection of tumor markers from breast cancer sera

There is an urgent need to identify relevant tumor markers showing high sensitivity and specificity for early diagnosis and prognosis of breast cancer. Protein microarrays have demonstrated to be cost-effective, high through-put and powerful tools for screening and identifying tumor markers with only minute samples. Autoantibodies directed against tumor-associated antigens (TAAs) were shown to be relevant tumor markers. However, due to the variability of immune response from one individual to another and depending on the type of cancer, detection of only one type of anti-TAA autoantibody is not sufficient to give a reliable and precise diagnosis. It is necessary to use a set of several TAAs for determining specific autoimmune profiles. Therefore, combining various TAAs on different surfaces could improve sensitivity and specificity for anti-TAA autoantibody detection. Herein a panel of 10 proteins, including well-known tumor-associated antigens (TAAs) and potential new biomarkers of breast cancer, were immobilized onto microstructured microarray under optimized conditions (spotting pH buffer, surface chemistry, blocking procedure), in order to determine an autoimmune signature of breast cancer. Sera from 29 breast cancer patients and 28 healthy donors were screened in sandwich immunoassays on the miniaturized system to detect the eventual presence of anti-TAAs autoantibodies. Results indicated that the detection level of each anti-TAA autoantibody in a given serum sample was strongly dependant on the surface chemistry. Combining five TAAs (p53, Hsp60, Hsp70, Her2-Fc, NY-ESO-1) on two different surface chemistries (NHS and APDMES) allowed the significant detection of more than 82% breast cancer sera.

Measuring biomarkers in wastewater as a new source of epidemiological information: Current state and future perspectives

The information obtained from the chemical analysis of specific human excretion products (biomarkers) in urban wastewater can be used to estimate the exposure or consumption of the population under investigation to a defined substance. A proper biomarker can provide relevant information about lifestyle habits, health and wellbeing, but its selection is not an easy task as it should fulfil several specific requirements in order to be successfully employed. This paper aims to summarize the current knowledge related to the most relevant biomarkers used so far. In addition, some potential wastewater biomarkers that could be used for future applications were evaluated. For this purpose, representative chemical classes have been chosen and grouped in four main categories: (i) those that provide estimates of lifestyle factors and substance use, (ii) those used to estimate the exposure to toxicants present in the environment and food, (iii) those that have the potential to provide information about public health and illness and (iv) those used to estimate the population size. To facilitate the evaluation of the eligibility of a compound as a biomarker, information, when available, on stability in urine and wastewater and pharmacokinetic data (i.e. metabolism and urinary excretion profile) has been reviewed. Finally, several needs and recommendations for future research are proposed.

A Novel DNA Biosensor Using a Ferrocenyl Intercalator Applied to the Potential Detection of Human Population Biomarkers in Wastewater

A new label-free electrochemical DNA (E-DNA) biosensor using a custom synthesized ferrocenyl (Fc) double-stranded DNA intercalator as a redox marker is presented. Single-stranded DNA (ssDNA) was co-immobilized on gold electrodes with 6-mecarpto-hexanol to control the surface density of the ssDNA probe, and hybridized with complementary DNA. The binding of the Fc intercalator to dsDNA was measured by differential pulse voltammetry. This new biosensor was optimized to allow the detection of single base pair mismatched sequences, able to detect as low as 10 pM target ssDNA with a dynamic range from 10 pM to 100 nM. DNA extracted from wastewater was analyzed by quantitative polymerase chain reaction targeting human-specific mitochondrial DNA (mtDNA). The aim of this approach is to enable the analysis of population biomarkers in wastewater for the evaluation of public health using wastewater-based epidemiology (WBE). The E-DNA biosensor was employed to detect human-specific mtDNA from wastewater before and after PCR amplification. The results demonstrate the feasibility of detecting human DNA biomarkers in wastewater using the developed biosensor, which may allow the further development of DNA population biomarkers for public health using WBE.

Community sewage sensors for monitoring public health.

unskilled personnel at the site of sample collection. Emerging biosensing technologies will play a key role in the in situ quantitative analysis of biomarkers and pathogens in sewage due to rapid response times, low cost, minimal sample processing, high data resolution and ability to operate remotely. Community sewage sensors employed to detect biomarkers of health and diseases at a population-level have therefore the clear potential to provide real-time data for the assessment of community-wide health. Biosensors have emerged as powerful tools for the detection of disease biomarkers for both healthcare and environmental monitoring. A biosensor is a small device with a biological receptor (DNA, antibody, protein etc.) that generates a signal (electrochemical, optical, piezoelectric, nanomechanical, mass sensitive etc.) in the presence of an analytical target (analyte). Compared to conventional analytical tools, biosensors can provide rapid response times, ultrasensitive detection of biomolecules, and the potential to be miniaturized for portable assays requiring minimal sample processing. Moreover, this approach could be employed, not only for the detection of pathogens, but also for the monitoring of more general public health indicators such as obesity, diabetes, high blood pressure

Estimation of caffeine intake from analysis of caffeine metabolites in wastewater

Caffeine metabolites in wastewater were investigated as potential biomarkers for assessing caffeine intake in a population. The main human urinary metabolites of caffeine were measured in the urban wastewater of ten European cities and the metabolic profiles in wastewater were compared with the human urinary excretion profile. A good match was found for 1,7-dimethyluric acid, an exclusive caffeine metabolite, suggesting that might be a suitable biomarker in wastewater for assessing population-level caffeine consumption. A correction factor was developed considering the percentage of excretion of this metabolite in humans, according to published pharmacokinetic studies. Daily caffeine intake estimated from wastewater analysis was compared with the average daily intake calculated from the average amount of coffee consumed by country per capita. Good agreement was found in some cities but further information is needed to standardize this approach. Wastewater analysis proved useful to providing additional local information on caffeine use.

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.

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 0.1nM (14.9ngL-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.

G-quadruplex–hemin DNAzyme molecular beacon probe for the detection of methamphetamine

In this work, a simple, cost-effective, and label-free biosensor was constructed for methamphetamine (METH) detection. The biosensor consists of a G-quadruplex–hemin DNAzyme molecular beacon (DNAzyme MB), a METH aptamer, and a colorimetric substrate. The DNAzyme MB loses peroxidase activity when it hybridizes with the METH aptamer. In the presence of METH, DNAzyme MB dissociates from the inactive hybrid due to preferable hybridization of METH with the aptamer. This process recovers the activity of DNAzyme MB, which catalyzes a reaction with the colorimetric substrate to yield measurable signals. Under optimized conditions, a detection limit as low as 0.5 nM (74.6 ng L−1) was achieved. Common illicit drugs were found to have little interference on detection of METH. Recoveries of METH spiked in urines of addicts were greater than 85%. Good agreement was observed between METH concentrations in urines determined by the sensor and by liquid chromatography-tandem mass spectrometer. These results indicate that the G-quadruplex–hemin DNAzyme MB probe holds promise to detect METH not only in biological samples, but also in environmental matrices.

Rapid Veterinary Diagnosis of Bovine Reproductive Infectious Diseases from Semen Using Paper-Origami DNA Microfluidics

The health and well-being of cattle is an important issue in maintaining and increasing global agricultural output. In dairy production within low and middle income countries (LMICs), there is a significant biosensing challenge in detecting sexually transmitted infection (STI) pathogens during animal husbandry, due in part to difficulties associated with the limited infrastructure for veterinary medicine. Here we demonstrate low-cost, multiplexed, and sample-to-answer paper-origami tests for the detection of three bovine infectious reproductive diseases in semen samples, collected at a test site in rural India. Pathogen DNA from one viral pathogen, bovine herpes virus-1 (BoHV-1), and two bacteria (Brucella and Leptospira) was extracted, amplified (using loop-mediated isothermal amplification, LAMP), and detected fluorescently, enabling <1 pg (∼ from 115 to 274 copies per reaction) of target genomic DNA to be measured. Data was collected as a fluorescence signal either visually, using a low-cost hand-held torch, or digitally with a mobile-phone camera. Limits of detection and sensitivities of the paper-origami device for the three pathogens were also evaluated using pathogen-inoculated semen samples and were as few as 50 Leptospira organisms, 50 CFU Brucella, and 1 TCID50 BoHV-1. Semen samples from elite bulls at a germplasm center were also tested in double-blind tests, as a demonstrator for a low-cost, user-friendly point-of-care sensing platform, for in-the-field resource-limited regions. The sensors showed excellent levels of sensitivity and specificity, and for the first time a demonstrated ability of the application of paper microfluidics devices for the diagnosis multiple infectious diseases from semen samples.