Efficient capture and rapid detection of pathogenic bacteria from body fluids lead to early diagnostics of bacterial infections and significantly enhance the survival rate. We propose a universal ...nano/microfluidic device integrated with a 3D nanostructured detection platform for sensitive and quantifiable detection of pathogenic bacteria. Surface characterization of the nanostructured detection platform confirms a uniform distribution of hierarchical 3D nano‐/microisland (NMI) structures with spatial orientation and nanorough protrusions. The hierarchical 3D NMI is the unique characteristic of the integrated device, which enables enhanced capture and quantifiable detection of bacteria via both a probe‐free and immunoaffinity detection method. As a proof of principle, we demonstrate probe‐free capture of pathogenic Escherichia coli (E. coli) and immunocapture of methicillin‐resistant‐Staphylococcus aureus (MRSA). Our device demonstrates a linear range between 50 and 104 CFU mL−1, with average efficiency of 93% and 85% for probe‐free detection of E. coli and immunoaffinity detection of MRSA, respectively. It is successfully demonstrated that the spatial orientation of 3D NMIs contributes in quantifiable detection of fluorescently labeled bacteria, while the nanorough protrusions contribute in probe‐free capture of bacteria. The ease of fabrication, integration, and implementation can inspire future point‐of‐care devices based on nanomaterial interfaces for sensitive and high‐throughput optical detection.
A nanostructured platform embedded in a fluidic sample delivery is developed for sensitive detection of pathogenic bacteria. The integrated device features a detection platform based on hierarchical 3D nano‐/microislands (NMI) of gold, enabling direct capture, and rapid and quantifiable detection of bacteria. The performance of the device is studied by probe‐free detection of pathogenic Escherichia coli and immunodetection of methicillin‐resistant‐Staphylococcus aureus.
An electro-catalysis non-enzymatic electrode is proposed based on alloyed Pt/Ni nanowire arrays (NWAs) for the detection of glucose. The Pt/Ni NWAs were prepared by pulse electrodeposition of Pt and ...Ni within a nano-pore polycarbonate (PC) membrane followed by a chemical etching of the membrane. The electrode structure is characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resulting Pt/Ni NWAs electrode shows high electrocatalytic activities towards the oxidation of glucose in alkaline solution. Consequently, a sensitive amperometric detection of glucose is achieved under 0.45
V vs. SCE with a low detection limit of 1.5
μM within a wide linear range from 2
μM to 2
mM (
R
=
0.997). Furthermore, the oxidable species such as ascorbic acid and uric acid show no significant interference in determination of glucose. Finally, the experiment results reveal a very good reproducibility and high stability for the proposed Pt/Ni NWAs electrode.
► We fabricate a non-enzyme glucose sensor based on the alloyed nanowires of Pt/Ni–Co. ► We design the process on alternate deposition of metals from single bath. ► Cooperation of Pt, Ni and Co leads ...to good conductivity and catalytic activity. ► Cooperation of Pt, Ni and Co lowers the applied potential of detection in this electrode. ► This electrode provides good current response in detection of low glucose amount.
A nanowire arrays system consisting of an ordered configuration of Pt, Ni and Co was constructed in single-bath solution through pulse electrodeposition. This structure was evaluated as a potential amperometric non-enzymatic sensor to detect glucose in alkaline solution. We observed a strong and fast amperometric response at low applied potential of 0.4V vs. SCE over linear ranges of 0–0.2mM and 0.2–8mM glucose with sensitivities of 1125 and 333μAmM−1cm−2, respectively. We also observed a low detection limit for glucose of 1μM. Correlation of the electronic and geometric modifications with the electrochemical performance characteristics enhanced catalytic activity of the electrode by applying the Ni and Co components to Pt nanowires structure. The electrode showed good analytical performance and high selectivity with no interference from other oxidable species, demonstrating its promise for developing an effective glucose sensor.
In article number 1801893, Sara Mahshid and co‐workers develop a nanostructured fluidic device for sensitive analysis of pathogenic bacteria based on a hierarchical nano/micro‐islands detection ...platform enabling direct, rapid, and quantifiable detection of bacteria. Performance of the integrated device in probe‐free optical detection of pathogenic bacteria such as Escherichia coli and optoimmunocapturing of antibiotic resistant bacteria such as methicillin‐resistant‐Staphylococcus‐aureus shows promise in future point‐of‐care devices.
A simple modified TiO(2) nanotubes electrode was fabricated by electrodeposition of Pd, Pt and Au nanoparticles. The TiO(2) nanotubes electrode was prepared using the anodizing method, followed by ...modifying Pd nanoparticles onto the tubes surface, offering a uniform conductive surface for electrodeposition of Pt and Au. The performance of the modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry methods. The Au/Pt/Pd/TiO(2) NTs modified electrode represented a high sensitivity towards individual detection of dopamine as well as simultaneous detection of dopamine and uric acid using 0.1 M phosphate buffer solution (pH 7.00) as the base solution. In both case, electro-oxidation peak currents of dopamine were linearly related to accumulated concentration over a wide concentration range of 5.0 × 10(-8) to 3.0 × 10(-5) M. However in the same range of dopamine concentration, the sensitivity had a significant loss at Pt/Pd/TiO(2) NTs electrode, suggesting the necessity for Au nanoparticles in modified electrode. The limit of the detection was determined as 3 × 10(-8) M for dopamine at signal-to-noise ratio equal to 3. Furthermore, the Au/Pt/Pd/TiO(2) NTs modified electrode was able to distinguish the oxidation response of dopamine, uric acid and ascorbic acid in mixture solution of different acidity. It was shown that the modified electrode possessed a very good reproducibility and long-term stability. The method was also successfully applied for determination of DA in human urine samples with satisfactory results.
Electrochemical biosensors combine the selectivity of electrochemical signal transducers with the specificity of biomolecular recognition strategies. Although they have been broadly studied in ...different areas of diagnostics, they are not yet fully commercialized. During the COVID-19 pandemic, electrochemical platforms have shown the potential to address significant limitations of conventional diagnostic platforms, including accuracy, affordability, and portability. The advantages of electrochemical platforms make them a strong candidate for rapid point-of-care detection of SARS-CoV-2 infection by targeting not only viral RNA but antigens and antibodies. Herein, we reviewed advancements in electrochemical biosensing platforms towards the detection of SARS-CoV-2 through studying similar viruses.
•The complicated nature of conventional tests restricted the availability and distribution of COVID-19 tests.•Electrochemical detection methods can stand as potential rapid tests for the diagnosis of COVID-19.•Electrochemical biosensors combine signal selectivity and molecular specificity for rapid accurate detection of SARS-CoV-2.•The electrochemical biosensors demonstrate trail-blazing sensitivity and specificity, outmatching conventional assays.
The last pandemic exposed critical gaps in monitoring and mitigating the spread of viral respiratory infections at the point‐of‐need. A cost‐effective multiplexed fluidic device (NFluidEX), as a ...home‐test kit analogous to a glucometer, that uses saliva and blood for parallel quantitative detection of viral infection and body's immune response in an automated manner within 11 min is proposed. The technology integrates a versatile biomimetic receptor based on molecularly imprinted polymers in a core–shell structure with nano gold electrodes, a multiplexed fluidic‐impedimetric readout, built‐in saliva collection/preparation, and smartphone‐enabled data acquisition and interpretation. NFluidEX is validated with Influenza A H1N1 and SARS‐CoV‐2 (original strain and variants of concern), and achieves low detection limit in saliva and blood for the viral proteins and the anti‐receptor binding domain (RBD) Immunoglobulin G (IgG) and Immunoglobulin M (IgM), respectively. It is demonstrated that nanoprotrusions of gold electrodes are essential for the fine templating of antibodies and spike proteins during molecular imprinting, and differentiation of IgG and IgM in whole blood. In the clinical setting, NFluidEX achieves 100% sensitivity and 100% specificity by testing 44 COVID‐positive and 25 COVID‐negative saliva and blood samples on par with the real‐time quantitative polymerase chain reaction (p < 0.001, 95% confidence) and the enzyme‐linked immunosorbent assay.
The authors present a nanostructured microfluidic electrochemical multiplexed device (NFluidEX) for parallel quantitative detection of viral proteins and antibodies in untreated saliva and whole blood within 11 minutes. This point‐of‐care platform is clinically and quantitatively validated with viral respiratory viruses to yield 100% sensitivity and 100% specificity against gold standard methods.
Rapid diagnostic testing has become a mainstay of patient care, using easily obtained samples such as blood or urine to facilitate sample analysis at the point‐of‐care. These tests rely on the ...detection of disease or organ‐specific biomarkers that have been well characterized for a particular disorder. Currently, there is no rapid diagnostic test for hearing loss, which is one of the most prevalent sensory disorders in the world. In this review, potential biomarkers for inner ear‐related disorders, their detection, and quantification in bodily fluids are described. The authors discuss lesion‐specific changes in cell‐free deoxyribonucleic acids (DNAs), micro‐ribonucleic acids (microRNAs), proteins, and metabolites, in addition to recent biosensor advances that may facilitate rapid and precise detection of these molecules. Ultimately, these biomarkers may be used to provide accurate diagnostics regarding the site of damage in the inner ear, providing practical information for individualized therapy and assessment of treatment efficacy in the future.
Blood‐based biomarkers could precisely diagnose inner ear disorders in the future. The current lack of knowledge about specific biomarkers has been the main challenge for the development of blood‐based diagnostics. This review summerizes the current knowledge of inner ear biomarkers and how to effectively detect them, to facilitate the design of novel diagnostic strategies.
This review, with 201 references, describes the recent advancement in the application of carbonaceous nanomaterials as highly conductive platforms in electrochemical biosensing. The electrochemical ...biosensing is described in introduction by classifying biosensors into catalytic-based and affinity-based biosensors and statistically demonstrates the most recent published works in each category. The introduction is followed by sections on electrochemical biosensors configurations and common carbonaceous nanomaterials applied in electrochemical biosensing, including graphene and its derivatives, carbon nanotubes, mesoporous carbon, carbon nanofibers and carbon nanospheres. In the following sections, carbonaceous catalytic-based and affinity-based biosensors are discussed in detail. In the category of catalytic-based biosensors, a comparison between enzymatic biosensors and non-enzymatic electrochemical sensors is carried out. Regarding the affinity-based biosensors, scholarly articles related to biological elements such as antibodies, deoxyribonucleic acids (DNAs) and aptamers are discussed in separate sections. The last section discusses recent advancements in carbonaceous screen-printed electrodes as a growing field in electrochemical biosensing. Tables are presented that give an overview on the diversity of analytes, type of materials and the sensors performance. Ultimately, general considerations, challenges and future perspectives in this field of science are discussed. Recent findings suggest that interests towards 2D nanostructured electrodes based on graphene and its derivatives are still growing in the field of electrochemical biosensing. That is because of their exceptional electrical conductivity, active surface area and more convenient production methods compared to carbon nanotubes.
Graphical abstract
Schematic representation of carbonaceous nanomaterials used in electrochemical biosensing. The content is classified into non-enzymatic sensors and affinity/ catalytic biosensors. Recent publications are tabulated and compared, considering materials, target, limit of detection and linear range of detection.
Photoelectrochemical (PEC) sensing systems are promising candidates for detecting low concentrations of biological molecules; they are particularly encouraging when offered in a non-enzymatic format. ...A pitfall of non-enzymatic PEC sensors is their specificity. This, however, is often resolved by utilizing inorganic nanocatalyst. Here, we describe a novel non-enzymatic sunlight-driven PEC sensor based on cobalt phosphate (Co-Pi) deposition on a one-dimensional titanium dioxide (1D-TiO2) nanorod array for the ultra-low detection of glucose. The 1D-TiO2 nanorod array was prepared through a simple hydrothermal method and modified with Co-Pi using photo-assisted electrodeposition. The result was a microscale fluidic reactor. The modified electrodes with various Co-Pi thicknesses photocatalyst were characterized through a variety of techniques, including HRTEM, XRD, UV–vis spectroscopy, electrochemical impedance spectroscopy, and chronoamperometry. The characterization methods served to study and confirm the optimal electrode structure. The novel 1D-TiO2/Co-Pi electrode exhibited enhanced absorbance in the visual range of the nanorods with increased photoactivity and no drastic modification of the array’s surface. The PEC sensor microscale reactor exhibited a low limit of detection of 0.031 nM and a high sensitivity of 900 μA mM−1 cm−2 over a linear range of 0.1–10000 nM, demonstrating ultrasensitive detection of glucose. Overall, the surface modification of TiO2 by Co-Pi improved the sensor properties resulting in high selectivity, high stability, and high reproducibility.
•Developing an improved sunlight-driven nanostructured photoelectrochemical sensor.•Conducting a complete study of the surface and opto/electrical properties.•Validating the sensor platform by targeting glucose in human plasma and buffer.•Facile implementation in industrial and clinical settings.•The first label-free and portable microscale reactor for non-enzymatic detection.
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