Dry Chemistry-Based Bipolar Electrochemiluminescence Immunoassay Device for Point-of-Care Testing of Alzheimer-Associated Neuronal Thread Protein.

In this study, we developed, for the first time, a novel dry chemistry-based bipolar electrochemiluminescence (ECL) immunoassay device for point-of-care testing (POCT) of Alzheimer-associated neuronal thread protein (AD7c-NTP), where the ECL signals were automatically collected and analyzed after the sample and buffer solutions were manually added onto the immunosensor. The proposed immunoassay device contains an automatic ECL analyzer and a dry chemistry-based ECL immunosensor fabricated with a screen-printed fiber material-based chip and a three-dimensional (3D)-printed shell. Each pad of the fiber material-based chip was premodified with certain reagents for immunoreaction and then assembled to form the ECL immunosensor. The self-enhanced ECL of the Ru(II)-poly-l-lysine complex and the lateral flow fiber material-based chip make the addition of coreactants and repeated flushing unnecessary. Only the sample and buffer solutions are added to the ECL immunosensor, and the process of ECL detection can be completed in about 6 min using the proposed automatic ECL analyzer. Under optimized conditions, the linear detection range for AD7c-NTP was 1 to 104 pg/mL, and the detection limit was 0.15 pg/mL. The proposed ECL immunoassay device had acceptable selectivity, stability, and reproducibility and had been successfully applied to detect AD7c-NTP levels in human urine. In addition, the accurate detection of AD7c-NTP and duplex detection of AD7c-NTP and apolipoprotein E ε4 gene were also validated. It is believed that the proposed ECL immunoassay device may be a candidate for future POCT applications.

Electrochemical Cloth-Based DNA Sensors (ECDSs): A New Class of Electrochemical Gene Sensors.

Electrochemical (EC) sensors have been widely developed for DNA detection, but they are seldom used in a simple, economic, and efficient manner. In this work, for the first time, EC cloth-based DNA sensors (ECDSs) are developed as a new class of EC DNA sensors, without the need for cumbersome chip fabrication and high-cost peripheral facilities. Carbon ink- and solid wax-based screen printing were used to produce ultracheap sensing devices (the cost of one sensor is estimated to be $0.045). Also, a CdTe QDs/MWCNTs nanocomposite (CdTe-MWCNTs) was applied to modify the sensing interface to obtain a stronger EC signal. Specifically, the newly developed double linear hybridization chain reaction (DL-HCR) greatly amplified the EC signal, relative to the conventional linear HCR. Under optimized conditions, target DNA (TD) samples (75-bp DNA fragments prepared via PCR amplification) were determined in a range from 20 fM to 5 nM, with a detection limit of 8.74 fM and relative standard deviations of 2.04% and 4.75% for intra- and inter-assays at 50 pM TD, respectively. Additionally, the ECDSs had an acceptable storage stability and high selectivity. Importantly, the ECDSs, coupled with simple enzyme digestion, could detect genomic DNA from Listeria monocytogenes (L. monocytogenes), and a detection limit of 0.039 ng/µL was obtained. When coupled with enzyme digestion and PCR amplification, the ECDSs could determine L. monocytogenes in milk samples, with detection limits of approximately 1.64 × 104 and 11 CFU/mL. These results demonstrate that the method offers a broad prospect for cost-effective, reliable, and highly sensitive gene-sensing applications.

Ultrasensitive cloth-based microfluidic chemiluminescence detection of Listeria monocytogenes hlyA gene by hemin/G-quadruplex DNAzyme and hybridization chain reaction signal amplification.

In this work, a cloth-based chemiluminescence (CL) biosensor has been firstly presented for highly sensitive determination of long PCR amplicons. Under the action of a hybridization chain reaction, a good deal of hemin/G-quadruplex DNAzyme molecules are produced, which can effectively enhance the CL signal. Moreover, effective cloth-based DNA biosensors can be fabricated by sequential wax screen-printing and surface-modification processes. Especially, the integration of a desirable hydrophobic barrier and gravity/capillary flow onto the flow channel of the cloth-based device makes the biosensor easy to be fabricated and to be associated with a flow CL. For the luminol/H2O2-based CL system, the signals are triggered by the hemin/G-quadruplex DNAzyme and are recorded by a low-cost CCD. Under optimized conditions, the determination range of target DNA is 0.002-20,000 pM and its limit of detection is calculated to be 1.1 fM. The results show that the proposed CL biosensor has a good analytical performance, such as high detectability and specificity, wide linear range, and receivable reproducibility and stability. Finally, the proposed biosensor is proven by the fact that this method can successfully detect the target DNA prepared from the Listeria monocytogenes-spiked milk samples. Therefore, it is believed to have the potential application prospects in food safety and environmental monitoring. Graphical abstract.

An electrochemiluminescence cloth-based biosensor with smartphone-based imaging for detection of lactate in saliva.

Cloth fabrics and smartphones have become the two things people are most familiar with. Particularly, smartphones are used as portable personal computers, revolutionizing communication and lifestyle. Here, screen-printing technology is applied to fabricate carbon electrodes and electrochemical chambers on a single hydrophilic cloth, while the cloth-based electrochemiluminescence (ECL) signals are read out by using an inexpensive smartphone. Therefore, the ECL detection is available in both low-cost disposable sensors and a portable format, which may be very suitable to be used as a non-invasive monitoring tool for medical diagnostics. As a proof-of-principle, lactate oxidase is immobilized onto the working electrode for the lactate measurement. Under optimized conditions, the lactate levels can be quantified over the range of 0.05-2.5 mM, with a detection limit of 0.035 mM and the relative standard deviations of 4.7%, 5.2% and 5.0% for 0.05, 0.5 and 2.5 mM lactate (n = 5). In addition, the proposed biosensor has an acceptable stability and selectivity. Finally, the ECL biosensor is successfully applied for the determination of lactate in human saliva. These results show that the presented ECL platform has the potential to be applied to non-invasively detect a variety of analytes of medical interest.

A novel screen-printed microfluidic paper-based electrochemical device for detection of glucose and uric acid in urine.

A novel screen-printed microfluidic paper-based analytical device with all-carbon electrode-enabled electrochemical assay (SP-ACE-EC-µPAD) has been developed. The fabrication of these devices involved wax screen-printing, which was simple, low-cost and energy-efficient. The working, counter and reference electrodes were screen-printed using carbon ink on the patterned paper devices. Different wax screen-printing processes were examined and optimized, which led to an improved method with a shorter heating time (~5 s) and a lower heating temperature (75 °C). Different printing screens were examined, with a 300-mesh polyester screen yielding the highest quality wax screen-prints. The carbon electrodes were screen-printed on the µPADs and then examined using cyclic voltammetry. The analytical performance of the SP-ACE-EC-µPADs for the detection of glucose and uric acid in standard solutions was investigated. The results were reproducible, with a linear relationship [R(2) = 0.9987 (glucose) or 0.9997 (uric acid)] within the concentration range of interest, and with detection limits as low as 0.35 mM (glucose) and 0.08 mM (uric acid). To determine the clinical utility of the µPADs, chronoamperometry was used to analyze glucose and uric acid in real urine samples using the standard addition method. Our devices were able to detect the analytes of interest in complex real-world biological samples, and have the potential for use in a wide variety of applications.

A Novel One-Step Fabricated, Droplet-Based Electrochemical Sensor for Facile Biochemical Assays.

A simple, novel concept for the one-step fabrication of a low-cost, easy-to-use droplet-based electrochemical (EC) sensor is described, in which the EC reagents are contained in a droplet and the droplet assay is operated on a simple planar surface instead of in a complicated closed channel/chamber. In combination with an elegant carbon electrode configuration, screen-printed on a widely available polyethylene terephthalate (PET) substrate, the developed sensor exhibits a stable solution-restriction capacity and acceptable EC response, and thus can be used directly for the detection of different analytes (including ascorbic acid (AA), copper ions (Cu(2+)), 2'-deoxyguanosine 5'-triphosphate (dGTP) and ferulic acid (FA)), without any pretreatment. The obtained, acceptable linear ranges/detection limits for AA, Cu(2+), dGTP and FA are 0.5-10/0.415 mM, (0.0157-0.1574 and 0.1574-1.5736)/0.011 mM, 0.01-0.1/0.008 mM and 0.0257-0.515/0.024 mM, respectively. Finally, the utility of the droplet-based EC sensor was demonstrated for the determination of AA in two commercial beverages, and of Cu(2+) in two water samples, with reliable recovery and good stability. The applicability of the droplet-based sensor demonstrates that the proposed EC strategy is potentially a cost-effective solution for a series of biochemical sensing applications in public health, environmental monitoring, and the developing world.

A dry chemistry-based self-enhanced electrochemiluminescence lateral flow immunoassay sensor for accurate sample-to-answer detection of luteinizing hormone.

BACKGROUND: Colorimetric lateral flow immunoassay (LFIA) is a widely used point-of-care testing (POCT) technology, while it has entered a bottleneck period because of low detection sensitivity, expensive preparation materials, and incapable quantitative detection. Therefore, it is necessary to develop a novel POCT method that is ultrasensitive, simple, portable, and capable of accurately detecting biomarkers in biofluids daily, particularly for pregnancy preparation and early screening of diseases. RESULT: In this work, a novel dry chemistry-based self-enhanced electrochemiluminescence (DC-SE-ECL) LFIA sensor is introduced for accurate POCT of luteinizing hormone (LH). The proposed DC-SE-ECL immunosensor significantly improves the detection sensitivity through the Poly-l-Lysine (PLL)-based SE-ECL probe and cathode modification of closed bipolar electrode (C-BPE). Additionally, a new type of C-BPE configuration is designed for easily performing the LFIA. And, two standalone absorbent pads are symmetrically arranged below the reporting channel of the electrode pad to decease useless residues on the detection pad, which further improves the detection performance. Under optimized conditions, the proposed LFIA sensor has a low limit of detection (9.274 µIU mL-1) and a wide linear dynamic range (0.01-100 mIU mL-1), together with good selectivity, repeatability and storage stability. SIGNIFICANCE: These results indicate that the proposed DC-SE-ECL method has the potential as a new tool for detecting biomarkers in clinical samples.

A novel PCR-free and label-free cloth-based DNA sensor for sensitive and rapid detection of Escherichia coli.

BACKGROUND: As is known to all, pathogenic bacteria have a serious impact on human health. The development of sensitive, simple, rapid and low-cost bacterial detection method is necessary. Nowadays, some conventional methods (such as plate count, polymerase chain reaction (PCR) and immunological techniques) can not meet the above needs. This work was aimed at providing a new method for addressing these unmet needs. RESULT: This study proposed a novel PCR-free and label-free DNA sensor based on multiple linear hybridization chain reaction (ML-HCR) and cloth-based closed bipolar electrochemiluminescence for sensitive and rapid detection of Escherichia coli (E. coli). The target DNA can be obtained from the E. coli genomic DNA by using the restriction enzyme instead of PCR. The auxiliary probe-triggered ML-HCR is carried out with continuous hybridization of two hairpin DNA, and as a result the double stranded DNA is formed to provide a large number of binding sites for Ru(bpy)32+. The whole detection is PCR-free and label-free, and thus the detection procedure is easier and faster. Under optimized conditions, the linear detection range was from 102 to 107 CFU/mL, and the detection limit was low to 38 CFU/mL. In addition, the proposed DNA sensor has an acceptable selectivity, stability and reproducibility, and is successfully applied to detect E. coli in milk samples with the recoveries from 96.24% to 105.98%. SIGNIFICANCE: The proposed DNA sensor has broad application prospects in the fields of bacterial detection and gene diagnose. Further, this method has potential to be extended for establishing miniaturized, integrated, and automated detection system.

A cloth-based single-working-electrode electrochemiluminescence sensor for simultaneous detection of diabetes complication markers.

As one of the most common noninfectious diseases, diabetes and diabetic complications (DDC) have attracted great attention in the field of life and health. However, simultaneous detection of DDC markers usually requires labor- and time-consuming steps. Here, a novel cloth-based single-working-electrode electrochemiluminescence (SWE-ECL) sensor was designed for the simultaneous detection of multiple DDC markers. For this sensor, three independent ECL cells are distributed on the SWE, which is a simplification of the configuration of traditional sensors for simultaneous detection. In this way, the modification processes and ECL reactions occur at the back of the SWE, eliminating the adverse effects caused by human intervention on the electrode. Under optimized conditions, glucose, uric acid and lactate were determined, with corresponding linear dynamic ranges of 80-4000 µM, 45-1200 µM and 60-2000 µM, and detection limits of 54.79 µM, 23.95 µM and 25.82 µM, respectively. In addition, the cloth-based SWE-ECL sensor exhibited good specificity and satisfactory reproducibility, and its actual application potential was verified by measuring complex human serum samples. Overall, this work developed a simple, sensitive, low-cost and rapid method for the simultaneous quantitative determination of multiple markers related to DDC and demonstrated a new route for multiple-marker detection.

Point-of-care detection of glycated hemoglobin using a novel dry chemistry-based electrochemiluminescence device.

As a good biomarker to reflect the average level of blood glucose, glycated hemoglobin (HbA1c) is mainly used for long-term glycemic monitoring and risk assessment of complications in diabetic patients. Previous analysis methods for HbA1c usually require complex pretreatment processes and large-scale biochemical analyzers, which makes it difficult to realize the point-of-care testing (POCT) of HbA1c. In this work, we have proposed a three-electrode dry chemistry-based electrochemiluminescence (ECL) biosensor and its self-contained automatic ECL analyzer. In this enzymatic biosensor, fructosyl amino-caid oxidase (FAOD) reacts with the hydrolysis product of HbA1c, and the produced hydrogen peroxide further reacts with luminol under the appropriate driving voltage, generating photons to realize the quantitative detection of HbA1c. Under optimized conditions, the biosensors have a good linear response to different concentrations of fructosyl valine (FV) ranging from 0.05 to 2 mM, with a limit of detection of 2 µM. The within-batch variation is less than 15%, and the biosensors still have 78% of the initial response after the accelerated aging test of 36 h at 37 °C. Furthermore, the recoveries for different concentrations of samples in whole blood were within 92.3-99.7%. These results illustrate that the proposed method has the potential for use in POCT of HbA1c.

A dry chemistry-based electrochemiluminescence device for point-of-care testing of alanine transaminase.

Liver disease causes serious public health problems because of its high prevalence, particularly affecting low- and middle-income countries. Alanine transaminase (ALT) is considered to be one of the most sensitive indicators for diagnosing liver disease. Although many strategies have been reported for ALT detection, few of them have solved the problem of automatic detection. In this work, for the first time, a dry chemistry-based electrochemiluminescence (DC-ECL) device is developed for point-of-care testing (POCT) of ALT, achieving real sample-to-answer detection. The proposed DC-ECL device consists of the following two components: (a) a DC-ECL chip consisting of the outer shell (including the top cap and pedestal) and detection layer (including the baseplate, electrode pad and carrier pad) and (b) an automatic ECL analyzer mainly including the data processing and instrument control unit, imaging detection unit, electrochemical reaction excitation unit, open detection window unit and rechargeable power supply. Under optimized conditions, the device had a wide detection range (0-1000 U/L), the ECL intensity linearly increased with ALT concentration (5-50 U/L) and logarithmic ALT concentration (50-1000 U/L), and the limit of detection was calculated to be 1.702 U/L. In addition, the DC-ECL device had the ability to measure ALT levels in human serum samples and showed acceptable selectivity, stability and repeatability. These results reveal that the DC-ECL device can overcome the disadvantages of traditional methods for ALT detection (such as high cost and requirement of professional technicians) and potentially opens the door to the development of similar POCT analyzers.

A microfluidic cloth-based photoelectrochemical analytical device for the detection of glucose in saliva.

Photoelectrochemical (PEC) detection is a widely used detection method that uses light to stimulate and photocurrent signals to detect the target. Due to the disengagement of the excitation unit and the detection unit, the PEC background signal is reduced, and the detection sensitivity is improved. In this work, we report the first demonstration of PEC detection for microfluidic cloth-based analytical devices (µCADs). Using PEC µCADs integrated with cadmium sulfide quantum dots (CdS QDs) and multiwalled carbon nanotubes (MWCNTs), the nonenzymatic, sensitive and rapid measurement of glucose in saliva has been achieved. For the cloth-based device, the PEC reaction zone and cloth-based electrodes can be fabricated by inexpensive wax-based and carbon ink-based screen-printing, respectively. By the layer-by-layer method, the as-prepared poly (dimethyl diadly ammonium chloride-functionalized) MWCNTs (PDDA-MWCNTs) and CdS QDs are successively adsorbed onto the working electrode surface of the cloth-based device. In the presence of an excitation source and glucose, the CdS QDs generate a strong oxidizing electron hole that can then continuously oxidize glucose to produce an electrical signal for glucose detection. Under optimized conditions, a linear dependence is obtained between the PEC signal and glucose concentrations in the range of 0.05-1000 µM with a detection limit of 15.99 nM. In the detection range, the cloth-based device also shows acceptable selectivity, reproducibility, and long-term stability. Moreover, the method has been implemented for the detection of glucose in real saliva samples, suggesting good potential for biochemical applications.

Novel cloth-based closed bipolar solid-state electrochemiluminescence (CBP-SS-ECL) aptasensor for detecting carcinoembryonic antigen.

This study involved the construction of a novel cloth-based CBP-SS-ECL aptasensor by introducing proximity hybridisation (PH) and solid-state electrochemiluminescence (SS-ECL) into a closed bipolar (CBP) electrochemistry system. Screen-printing was used to fabricate the cloth-based aptasensors, and PH and aptamers provided good selectivity for the sensor. Furthermore, the CBP-SS-ECL sensing interface was produced by immobilising of Ru(bpy)32+- doped silica nanoparticles (Ru-Si-NPs) on the anode of closed bipolar electrode (C-BPE). PH product (PP) was formed due to the target (carcinoembryonic antigen, CEA), and then the PP opened the Au NP-labelled capture probe (Au-CP) on the C-BPE anode (CBA), allowing ferrocene carboxylic acid (FcA) close to the CBA surface and Au NPs away from the surface. The corresponding quenching and enhancement of ECL signal by FcA and Au NPs, respectively, markedly enhanced ECL signal. This aptasensor successfully achieved quantitative detection of CEA, with a linear detection range of 5-100000 pg mL-1 and a detection limit of 1.6 pg mL-1. The described aptasensor showed an acceptable sensitivity, selectivity, stability, and ability to detect CEA levels in complex human serum samples. In particular, this aptasensor showed satisfactory versatility, indicating its potential for simultaneous detection of CEA and K-ras gene.

Shared-cathode closed bipolar electrochemiluminescence cloth-based chip for multiplex detection.

Electrochemiluminescence (ECL) chips have been widely used in the field of medical diagnosis. However, most of these chips currently in use are costly and require high amounts of sample. In this work, we present, for the first time, a shared-cathode closed bipolar electrochemiluminescence (SC-CBP-ECL) cloth-based chip, which can be used for multiplex detection. The SC-CBP-ECL chips ($0.03-0.05 for each chip) are manufactured using carbon ink- and wax-based screen-printing techniques, without the need for expensive and complex fabrication equipment. Under optimised conditions, the SC-CBP-ECL chips were successfully used for coinstantaneous detection of glucose in double ECL systems (i.e., Ru(bpy)32+ and luminol), with corresponding linear ranges of 0.05-1 mM and 0.05-10 mM, and detection limits of 0.0382 mM and 0.0422 mM. To our knowledge, this is the first report on the application of fibre material-based closed bipolar electrodes (C-BPE) combined with double ECL systems. Furthermore, the SC-CBP-ECL chips exhibit an acceptable specificity and good reproducibility and stability and can be used for glucose detection in human serum samples with a good agreement compared with the clinical method. Finally, the SC-CBP-ECL chips could be successfully used for simultaneous detection of seven glucose samples and also show potential for simultaneous detection of three different targets (hydrogen peroxide [H2O2], glucose, and uric acid [UA]). Therefore, we believe that the chip described in this study has broad potential application in the field of cost-effective multiplex detection.

A dry chemistry-based ultrasensitive electrochemiluminescence immunosensor for sample-to-answer detection of Cardiac Troponin I.

Dry chemistry-based fluorescence or colorimetric immunosensors have been widely applied for point-of-care testing (POCT). However, dry chemistry-based electrochemiluminescence (ECL) immunosensors have not been reported for real sample-to-answer detection. Herein, a dry chemistry-based sample-to-answer, ultrasensitive closed bipolar electrode-ECL (CBP-ECL) immunosensor based on lateral flow assay has been firstly designed for POCT of Cardiac Troponin I (cTnI). The CBP-ECL immunosensor consisted of a fiber material-based chip and an outer shell, which were easily and affordably fabricated by screen-printing and 3D printing, respectively. Additionally, the Ru(Ⅱ)-L-Cys composite, as a self-enhanced ECL probe, was firstly introduced into the sandwich CBP-ECL immunosensor. The ECL signal generated by labeled antibody functionalized Ru(Ⅱ)-L-Cys could quantify cTnI sensitively. Therefore, the immunosensor had a wide linear range (0.001-100 ng/mL) and acceptable sensitivity (0.4416 pg/mL), together with superior specificity and good reproducibility and stability. Furthermore, the immunosensor was capable of detection of cTnI in serum, with recoveries of 97.3-103.4%. For detection of cTnI in plasma samples, the results of the proposed CBP-ECL had a good correlation with those of the clinical method. Importantly, the analysis process easily operated, and completed in 7 min. These results illustrated that the proposed immunosensor effectively combined the high sensitivity of CBP-ECL with the simplicity of lateral flow assay, and provided a promising POCT avenue for early diagnosis of acute myocardial infarction (AMI) and other diseases.

Integrated microfluidic reverse transcription-polymerase chain reaction for rapid detection of food- or waterborne pathogenic rotavirus.

The development of microfluidic tools for nucleic acid analysis has become a burgeoning area of research during the postgenome era. Here we have developed a microfluidic device that integrates reverse transcription (RT) and polymerase chain reaction (PCR) with online fluorescence detection to realize a rapid detection system for performing both genetic amplification and product analysis. The microfluidic device mainly comprises a grooved copper heating block for RT and a heated cylinder for amplification. To expedite the analysis process, we combined the continuous-flow PCR with an online fluorescence detection system that allows analysis of amplification products within 1 min. Rotaviruses are worldwide enteric pathogens in humans and animals responsible for a significant burden of disease through person-to-person transmission and exposure to contaminated foods and water. In this study, rotavirus from stool specimens was successfully amplified and detected using the RT-PCR microfluidic system within 1 h, and the limit of detection of the RNA concentration was estimated to be 3.6×10(4) copies µl(-1). Compared with a large-scale apparatus, the integrated microfluidic system presented here can perform rapid nucleic acid amplification and analysis, possibly making it a crucial platform for future diagnosis application.

Multichannel oscillatory-flow multiplex PCR microfluidics for high-throughput and fast detection of foodborne bacterial pathogens.

In the field of continuous-flow PCR, the amplification throughput in a single reaction solution is low and the single-plex PCR is often used. In this work, we reported a flow-based multiplex PCR microfluidic system capable of performing high-throughput and fast DNA amplification for detection of foodborne bacterial pathogens. As a demonstration, the mixture of DNA targets associated with three different foodborne pathogens was included in a single PCR solution. Then, the solution flowed through microchannels incorporated onto three temperature zones in an oscillatory manner. The effect factors of this oscillatory-flow multiplex PCR thermocycling have been demonstrated, including effects of polymerase concentration, cycling times, number of cycles, and DNA template concentration. The experimental results have shown that the oscillatory-flow multiplex PCR, with a volume of only 5 µl, could be completed in about 13 min after 35 cycles (25 cycles) at 100 µl/min (70 µl/min), which is about one-sixth of the time required on the conventional machine (70 min). By using the presently designed DNA sample model, the minimum target concentration that could be detected at 30 µl/min was 9.8 × 10(-2) ng/µl (278-bp, S. enterica), 11.2 × 10(-2) ng/µl (168-bp, E. coli O157: H7), and 2.88 × 10(-2) ng/µl (106-bp, L. monocytogenes), which corresponds to approximately 3.72 × 10(4) copies/µl, 3.58 × 10(4) copies/µl, and 1.79 × 10(4) copies/µl, respectively. This level of speed and sensitivity is comparable to that achievable in most other continuous-flow PCR systems. In addition, the four individual channels were used to achieve multi-target PCR analysis of three different DNA samples from different food sources in parallel, thereby achieving another level of multiplexing.

A novel cloth-based supersandwich electrochemical aptasensor for direct, sensitive detection of pathogens.

Traditional detection methods for food-borne pathogens are usually expensive and laborious, so there is an urgent need for an economical, facile and sensitive method. In this work, a novel cloth-based supersandwich electrochemical aptasensor (CSEA) is firstly developed for direct detection of pathogens. Carbon ink- and wax-based screen-printing is used to make cloth-based electrodes and hydrophilic/hydrophobic regions respectively to fabricate the sensing devices. Two well-designed, specific single-stranded DNA sequences arise a cascade hybridization reaction to form the DNA supersandwich (DSS) whose grooves can be inserted by methylene blue (MB), which effectively amplifies the current signal to greatly improve the detection sensitivity. Taking the detection of Salmonella typhimurium (S. typhimurium) as an example, the aptamers bind to S. typhimurium to form the target-aptamers complex, which can simultaneously bind to the capture probe and DSS, resulting in detection of S. typhimurium. Moreover, the addition of tail sequences of aptamer makes the proposed CSEA versatile. Under optimized conditions, the electrochemical signal increases linearly with the logarithm of S. typhimurium concentration over the range from 102 to 108 CFU mL-1, with a limit of detection of 16 CFU mL-1. Additionally, the CSEA efficiently determined the levels of S. typhimurium in milk samples. Experimental results illustrate that the fabricated CSEA is sensitive, specific, reproducible and stable. Moreover, when Ru(bpy)32+ replaces MB, the electrochemiluminescence (ECL) can be performed. Thus, for the proposed sensing strategy, the dual-mode detection of electrochemistry and ECL is easily realized.