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In this work, we report the first demonstration of chemiluminescence (CL) detection for microfluidic cloth-based analytical devices (μCADs). Wax screen-printing is used to make cloth channels or chambers, and enzyme-catalyzed CL reactions are imaged using an inexpensive charge coupled device (CCD). We first evaluate the relationship between the wicking rate and the length/width of cloth channel. For our device, the channel length and width between the loading and detection chambers are optimized to be 10 mm and 3 mm. Thus, the detection procedure can be accomplished in about 15 s on a cloth-based device (15×30 mm 2 ) by using 25-μL sample spotted on it. Next, several parameters affecting cloth-based CL intensity are studied, including exposure time, pH, and concentrations of luminol and enzyme. Under optimal conditions, a linear relationship is obtained between CL intensity and hydrogen peroxide (H 2 O 2 ) concentrations in the range of 0.5–5 mM with a detection limit of 0.46 mM. Finally, the utility of cloth-based CL is demonstrated for determination of H 2 O 2 residues in meat samples. On our device, the chicken meat soaked for 6 h with 3% H 2 O 2 can be detected. Moreover, the supernatant of grinded meat sample can be directly applied, without need for other treatments. We believe that μCADs with CL detection could provide a new platform of rapid and low-cost assays for use in areas such as food detection and environmental monitoring. [ABSTRACT FROM AUTHOR]

Graph Publisher's note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. The original article can be found online at https://doi.org/10.1007/s00216-020-02633-5 B Correction to: Analytical and Bioanalytical Chemistry b https://doi.org/10.1007/s00216-020-02633-5 The authors would like to call the reader's attention to the fact that, unfortunately, there was confusion regarding figure 3c in this manuscript. [Extracted from the article]

This paper describes the development of a paper-based microfluidic device that detects long DNA amplicons on the basis of hybridization reactions with a covalently immobilized DNA probe and biotin-labeled signal DNA strands, and chemiluminescent (CL) reactions catalyzed by a horseradish peroxidase (HRP)-streptavidin conjugate. The paper-based microfluidic CL biosensor is developed for detection of 198-bp DNA fragments obtained by PCR amplification of the Listeria monocytogenes hlyA gene, where the CL intensity is detected by a simple, inexpensive CCD. To our knowledge, the combined use of the CCD sensing and paper-based microfluidic CL detection is first proposed here. The paper-based device includes wax-screen printed channels, and further explores origami-type folds to create an easy-to-operate valve that makes it possible to successively wash the detection zone in-between hybridization steps. Compared with other paper-based wax-screen-printing methods, the proposed method is faster and needs lower heating temperature. In our DNA biosensor, CL signals generated using a HRP-luminol-H2O2 system are heightened with p-iodine phenol (PIP) and detected with a CCD system. Under optical conditions, a linear range of 1.94 × 10 −1 pmol/L to 1.94 × 10 4 pmol/L is achieved and the limit of detection is found to be 6.3 × 10 −2 pmol/L. And, this detection limit is 3–5 orders of magnitude lower than those obtained from other CCD-based microfluidic CL DNA assays. The results show that the proposed integration of paper-based microfluidics, CL method and CCD sensing offers great promises in providing a highly-sensitive, reliable and cost-effective solution for gene biosensing applications. [ABSTRACT FROM AUTHOR]

In this work, we for the first time reported a paperfluidic crossing-channel closed-BPE based electrochemiluminescence (P-3C-BPE-ECL) platform where multiple “band”-shaped C-BPEs are situated perpendicular to two parallel channels, and multiplex detection can be achieved in the reporting channel. The paperfluidic devices are easily fabricated by wax and carbon ink-based screen-printing processes. Under optimized conditions, the P-3C-BPE-ECL is applied to the quantitative analysis of hydrogen peroxide (H 2 O 2 ) and glucose, with corresponding linear ranges of 0.075–10 mM and 0.08–5 mM, and corresponding detection limits of 0.041 mM and 0.03 mM. To our knowledge, this is the first demonstration of paperfluidic C-BPE-ECL method for glucose determination. Based on its acceptable selectivity, the P-3C-BPE-ECL method is used for measurements of glucose in four complex samples (human serum and urine, wine, and glucose injection) and is compared with the traditional methods. The results indicate a good agreement and prove the reliability and accuracy of the proposed platform. Importantly, the proposed method is demonstrated to have the potential for duplex detection of glucose and uric acid, which intensively matches the requirement of those patients simultaneously suffering from diabetes and gout. Therefore, we believe that the P-3C-BPE-ECL could provide a new platform for wide biochemical applications. [ABSTRACT FROM AUTHOR]

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. 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. These results indicate that the proposed DC-SE-ECL method has the potential as a new tool for detecting biomarkers in clinical samples. [Display omitted] • A novel DC-SE-ECL LFIA sensor was applied for detection of LH. • The sensitivity was greatly improved through the SE-ECL probe and cathode modification. • The LFIA strip was easily fabricated by using various cloth materials. • The portable ECL analyzer was used for rapid immunodetection (about 6 min). • The detection limit was 9.274 μIU mL −1, and the linear range was from 0.01 to 100 mIU mL−1. [ABSTRACT FROM AUTHOR]

In this work, a solely gravity and capillary force-driven flow chemiluminescence (GCF-CL) paper-based microfluidic device has been proved for the first time as a new platform for inexpensive, usable, minimally-instrumented dynamic chemiluminescence (CL) detection of chromium (III) [Cr(III)], where an appropriate angle of inclination between the loading and detection zones on the paper produces a rapid flow of CL prompt solution through the paper channel. For this study, we use a cost-effective paper device that is manufactured by a simple wax screen-printing method, while the signal generated from the Cr(III)-catalyzed oxidation of luminol by H2O2 is recorded by a low-cost and luggable CCD camera. A series of GCF-CL affecting factors have been evaluated carefully. At optimal conditions, two linear relationships between GCF-CL intensities and the logarithms of Cr(III) concentrations are obtained in the concentration ranges of 0.025–35 mg/L and 50–500 mg/L separately, with the detection limit of 0.0245 mg/L for a less than 30 s assay, and relative standard deviations (RSDs) of 3.8%, 4.5% and 2.3% for 0.75, 5 and 50 mg/L of Cr(III) (n = 8). The above results indicate that the GCF-CL paper-based microfluidic device possesses a receivable sensitivity, dynamic range, storage stability and reproducibility. Finally, the developed GCF-CL is utilized for Cr(III) detection in real water samples. [ABSTRACT FROM AUTHOR]

Chemiluminescence (CL) has been widely applied in many fields, but it is rarely used in a very simple, economical but effective way. In this work, for the first time, the CL cloth-based glucose test sensors (CCGTSs) are developed as a new class of CL glucose sensors, with no need for complicated, expensive device fabrication and peripheral equipment. When integrated with desirable hydrophobic barrier in the flow channel and gravity/capillary flow induced by a difference in height between the loading zone and the detection zone, a single cloth-based device can perform the whole CL process involving two steps of enzyme reactions. The wax screen-printing approach is used to fabricate ultra-cheap CCGTSs, the glucose detection involves the enzymatic oxidation of glucose to gluconic acid and H 2 O 2 followed by the horseradish peroxidase (HRP)-catalyzed oxidation of luminol by H 2 O 2 , and the emitted CL signals are heightened with p-iodophenol (PIP) and imaged using an inexpensive, portable CCD camera. Under optimized conditions, glucose can be determined over the range of 0.1–100 mM, with a detection limit of 0.0948 mM and an analysis time of less than 5.5 min. Finally, the applicability and validity of the CCGTSs are demonstrated for the measurement of glucose in clinical urine and serum samples. Thus, the proposed sensors could provide great promise in applications in many areas, and may facilitate the achievement of point-of-care testing. [ABSTRACT FROM AUTHOR]

Flow chemiluminescence (CL) is widely applied for detection of heavy metal ions in environment, but it is seldom used in economical, practical, or affordable settings because non- and minimally instrumented flow driving is difficult to achieve. Here, we first report a gravity and capillary force-driven flow CL (GCF-CL) lab-on-cloth device, toward development of low-cost, easy-to-use, portable, minimally-instrumented platform for determination of trivalent chromium [Cr(III)] in water, where a difference in height between two zones on cloth creates a fast flow of CL trigger solution. Wax screen-printing was used to fabricate ultra-low-cost cloth-based devices, and the light emitted from the Cr(III)-catalysed oxidation of luminol by H 2 O 2 was imaged using an inexpensive portable CCD camera. Under optical conditions, Cr(III) could be determined over the range of 0.01–100 mg/L, with a detection limit of 6.2 μg/L, an analysis time of less than 30 s per sample, and RSDs of 6.2%, 3.1% and 1.7% for 0.05, 0.5 and 5 mg/L Cr(III) (n = 5). The proposed GCF-CL lab-on-cloth was successfully applied for measuring Cr(III) in water samples, with recoveries of 100.67-111.70% and RSDs of 4.73–6.88%. Thus, the presented method should have the potential for portable field applications in environmental and public health fields. [ABSTRACT FROM AUTHOR]

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) 3 2+ 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 [H 2 O 2 ], 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. [Display omitted] • A shared-cathode closed bipolar electrochemiluminescence (SC-CBP-ECL) is reported. • The combination of cloth-based C-BPE and double ECL system is presented. • The SC-CBP-ECL can be used for coinstantaneous detection of seven glucose samples. • The SC-CBP-ECL can be applied for simultaneous detection of three different targets. • The proposed multiplex detection method is cost-effective. [ABSTRACT FROM AUTHOR]