More than 783 million people worldwide are currently without access to clean and safe water. Approximately 1 in 5 cases of mortality due to waterborne diseases involve children, and over 1.5 million ...cases of waterborne disease occur every year. In the developing world, this makes waterborne diseases the second highest cause of mortality. Such cases of waterborne disease are thought to be caused by poor sanitation, water infrastructure, public knowledge, and lack of suitable water monitoring systems. Conventional laboratory-based techniques are inadequate for effective on-site water quality monitoring purposes. This is due to their need for excessive equipment, operational complexity, lack of affordability, and long sample collection to data analysis times. In this review, we discuss the conventional techniques used in modern-day water quality testing. We discuss the future challenges of water quality testing in the developing world and how conventional techniques fall short of these challenges. Finally, we discuss the development of electrochemical biosensors and current research on the integration of these devices with microfluidic components to develop truly integrated, portable, simple to use and cost-effective devices for use by local environmental agencies, NGOs, and local communities in low-resource settings.
Printed circuit boards (PCBs) offer a promising platform for the development of electronics-assisted biomedical diagnostic sensors and microsystems. The long-standing industrial basis offers ...distinctive advantages for cost-effective, reproducible, and easily integrated sample-in-answer-out diagnostic microsystems. Nonetheless, the commercial techniques used in the fabrication of PCBs produce various contaminants potentially degrading severely their stability and repeatability in electrochemical sensing applications. Herein, we analyse for the first time such critical technological considerations, allowing the exploitation of commercial PCB platforms as reliable electrochemical sensing platforms. The presented electrochemical and physical characterisation data reveal clear evidence of both organic and inorganic sensing electrode surface contaminants, which can be removed using various pre-cleaning techniques. We demonstrate that, following such pre-treatment rules, PCB-based electrodes can be reliably fabricated for sensitive electrochemical biosensors. Herein, we demonstrate the applicability of the methodology both for labelled protein (procalcitonin) and label-free nucleic acid (E. coli-specific DNA) biomarker quantification, with observed limits of detection (LoD) of 2 pM and 110 pM, respectively. The proposed optimisation of surface pre-treatment is critical in the development of robust and sensitive PCB-based electrochemical sensors for both clinical and environmental diagnostics and monitoring applications.
Sensitive and specific DNA biomarker detection is critical for accurately diagnosing a broad range of clinical conditions. However, the incorporation of such biosensing structures in integrated ...microfluidic devices is often complicated by the need for an additional labelling step to be implemented on the device. In this review we focused on presenting recent advances in label-free DNA biosensor technology, with a particular focus on microfluidic integrated devices. The key biosensing approaches miniaturized in flow-cell structures were presented, followed by more sophisticated microfluidic devices and higher integration examples in the literature. The option of full DNA sequencing on microfluidic chips via nanopore technology was highlighted, along with current developments in the commercialization of microfluidic, label-free DNA detection devices.
We report the development of a Lab-on-PCB DNA diagnostic platform, exploiting peptide nucleic acid (PNA) sequences as probes. The study demonstrates the optimization and characterization of two ...commercial PCB manufacturing gold electroplating processes for biosensing applications. Using an optimized ratio of PNA with a spacer molecule (MCH), the lowest limit of detection (LoD) to date for PCB-based DNA biosensors of 57 fM is reported. The study also showcases a fully integrated Lab-on-PCB microsystem designed for rapid detection, which employs PCB-integrated sample delivery, achieving DNA quantification in the 0.1–100 pM range for 5 μL samples analyzed within 5 min under continuous flow. The demonstrated biosensor proves the capability of PCB-based DNA biosensors for high sensitivity and paves the way for their integration in Lab-on-PCB DNA diagnostic microsystems.
•PNA probes successfully employed in PCB-based impedimetric DNA biosensors.•Importance of PCB electrode surface characteristics on sensor performance highlighted.•Lowest LoD to date (57fM) for PCB-implemented DNA biosensors reported.•Sensors further integrated with sample delivery PCB microfluidics.
Waterborne diseases are caused by microorganisms known as pathogens e.g., bacteria, viruses, protists etc. that are commonly spread through contaminated fresh water sources. Diseases caused by these ...pathogens are today one of the leading causes of infection and mortality. In low- and middle-income countries public health is steadily becoming an increasing risk, with increased development directly producing waste pollution carrying pathogens into freshwater sources. Examples of freshwater sources include reservoirs, rivers and wells with waste pollution being due to poor sanitation, agricultural runoff, illegal dumping etc. The result of this pollution is being further exacerbated by poor wastewater infrastructure, reduced public understanding as well as lack of diagnostic and monitoring systems. One strategy of improving public health is to develop small portable devices that are easy-to-use to monitor levels of waterborne pathogens in drinking water to avoid unnecessary disease from contaminated sources. To do this we aimed to develop an integrated biosensing device for the sensitive detection of highly selective DNA sequences related to several waterborne pathogens. The first study focusses on the development and optimisation of a biosensor assay using electrochemical impedance spectroscopy (EIS). The work looks at the optimisation of surface chemistry taking advantage of the passive adsorption of thiol groups to form a self-assembled monolayer (SAM). This is not only a relatively simple way of forming a sensing layer, but with the use of re-usable gold electrodes and E. coli specific thiolated ssDNA probes it is also cost-effective to optimise. This study also highlights the importance of different cleaning techniques for reusable gold electrodes and how this can impact ideal SAM formation for increasing probe-target interaction. The results of this study will act as a baseline for the ability of thiol self-assembled DNA probes to detect target sequences without any additional signal amplifying steps. The second study takes the assay from the first study a step further by integrating a post-signal amplification step using a redox-active intercalator. Intercalators are molecules that bind between the base pairs of the DNA duplex structure. In doing so, they can alter the secondary structure of the duplex and increase the electrostatic field. This particular work exploits a novel redox-active intercalator called cobalt-aqphen, Co(GA)2(aqphen)Cl. The cobalt acts as the redox-active ligand of the compound, while the addition of the extended planar aqphen ligand with conjugated anthraquinone which has been shown to increase binding affinity between the base pairs. Intercalation of this molecule enables the potential for amperometric and non-faradaic detection of target DNA sequences at much lower limits of detection (LOD) without the need for an additional redox couple. The third study develops a highly sensitive and selective assay integrating CRISPR/Cas-based SHERLOCK detection integrated with isothermal amplification, a conductive-polymer surface chemistry, peptide nucleic acid (PNA) probes and amperometric detection of TMB precipitation for signal-off function detection. This assay was used to demonstrate detection of both synthetic E. coli sequences as well as single-molecule SARS-CoV-2 viral RNA from unprocessed patient saliva. This assay can also be easily modified by altering the guide RNA that programmes the CRISPR/Cas enzyme to detect any target pathogen RNA. This provides great potential for multiplexed detection of multiple pathogen markers of clinically and environmentally relevant pathogens from a single point source sample. In conclusion, this thesis aims to describe methods of increasing the sensitivity and selectivity of target nucleic acid detection using methods of pre-signal amplification such as isothermal amplification integrated with CRISPR/Cas SHERLOCK diagnostics as well as post-signal amplification using redox-active intercalator molecules. It also aims to explore ways of combining these techniques together to create truly integrated, cost-effective ways of detecting multiple waterborne pathogens of interest.
Rapid, accurate and frequent detection of the RNA of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) and of serological host antibodies to the virus would facilitate the determination of ...the immune status of individuals who have Coronavirus disease 2019 (COVID-19), were previously infected by the virus, or were vaccinated against the disease. Here we describe the development and application of a 3D-printed lab-on-a-chip that concurrently detects, via multiplexed electrochemical outputs and within 2 h, SARS-CoV-2 RNA in saliva as well as anti-SARS-CoV-2 immunoglobulins in saliva spiked with blood plasma. The device automatedly extracts, concentrates and amplifies SARS-CoV-2 RNA from unprocessed saliva, and integrates the Cas12a-based enzymatic detection of SARS-CoV-2 RNA via isothermal nucleic acid amplification with a sandwich-based enzyme-linked immunosorbent assay on electrodes functionalized with the Spike S1, nucleocapsid and receptor-binding-domain antigens of SARS-CoV-2. Inexpensive microfluidic electrochemical sensors for performing multiplexed diagnostics at the point of care may facilitate the widespread monitoring of COVID-19 infection and immunity.A 3D-printed lab-on-a-chip allows for the concurrent rapid electrochemical detection of SARS-CoV-2 RNA in saliva and of anti-SARS-CoV-2 antibodies in saliva spiked with blood plasma.
Abstract Background Depression has become a critical global health problem, affecting millions of people. Cost-effective nonpharmacological treatment in community settings has been proposed to ...complement medical treatment. Short-term clay art therapy (CAT) is an alternative treatment that promotes the enhancement of various aspects of mental health for depressed individuals. Methods One-hundred and six adults with depression were randomized into a CAT group or visual art (VA) control group for six 2.5-h weekly sessions. Intervention effects were measured using the Beck Depression Inventory, 12-Item General Health Questionnaire (Chinese version), Body–Mind–Spirit Well-Being Inventory, and 20-Item Toronto Alexithymia Scale (Chinese version) at baseline, immediately postintervention (T1), and 3-weeks postintervention (T2). Result Multivariate analysis of covariance results indicated a more significant time × group effect for CAT than for VA on depressive signs, general health, and body–mind–spirit well-being (all p < 0.05). Significant within-groups changes were observed in these three aspects after treatment and at T2 (all p < 0.001) and in alexithymia at T2 ( p < 0.01) in the CAT group, but the change was nonsignificant in the VA group at T1 and T2. Limitations The homogeneity of the participants affected the generalizability of the study findings. The short-term postintervention follow-up (3 weeks) presented difficulties in demonstrating the long-term effects of CAT. Conclusions CAT can aid emotion regulation and benefit various aspects of mental health in adults. The short duration of the intervention suggests additional application value in treating depression. Further investigation is warranted regarding the potential effect of CAT on alleviating physical symptoms and improving social function.
Abstract
Objectives
Dementia interferes with older adults’ functioning in cognitive, daily, psychosocial, and neuroendocrine domains. The present study examined the psychophysiological effects of ...dance movement therapy (DMT) and physical exercise for older adults with dementia.
Methods
This randomized controlled trial recruited 204 older adults diagnosed with mild dementia into the DMT, exercise, or waitlist control group. Both DMT and exercise interventions had similar intensity and comprised 24 hr of intervention that spanned over 12 weeks. All participants completed self-report questionnaires on psychosocial well-being, daily functioning, neurocognitive assessments, and salivary cortisol measures at baseline and 3 follow-up measurements more than 1 year.
Results
The DMT group showed significant decreases in depression, loneliness, and negative mood (d = 0.33–0.42, p < .05) and improved daily functioning (d = 0.40, p < .01) and diurnal cortisol slope (d = 0.30, p < .01). The effects on daily functioning and cortisol slope remained at 1-year follow-up. The exercise group of matched intensity showed no significant effects on the outcomes.
Discussion
The study findings support the potential utility of DMT as a multifaceted intervention for improving various aspects of functioning in older adults with declining cognitive abilities. The lack of beneficial effects for our exercise intervention and long-term DMT effects highlights the need to maintain persistent levels of exercise with adequate intensity and duration.
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