Chemiluminescence detection for microfluidic cloth-based analytical devices (μCADs)

•CL detection is combined with μCADs to establish a novel CL biosensor.•The wax-screen-printing technology is used for patterning of μCADs.•A CCD detector is applied for cloth-based microfluidic CL detection.•The proposed method is applied to the determination of H2O2 residues in real meat samples.

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 mm2) 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 (H2O2) 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 H2O2 residues in meat samples. On our device, the chicken meat soaked for 6 h with 3% H2O2 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.