Self-assembled polydiacetylene (PDA) vesicles, with the
distinct
advantages of low-cost materials, simple preparation, and excellent
chromatic properties, can be perfectly combined with a colorimetric
strip for on-site inspection. Herein, without involving expensive
reagents and instruments, a visual colorimetric strip based on well-prepared
PDA vesicles was developed to analyze and monitor histamine in deep-sea
fish and its canned food. The standard calorimetric card for semiquantitative
detection of histamine was successfully prepared and the quantitative
detection can be further realized by analyzing the gray value using
ImageJ and “Color Grab” in a smart phone. After optimizing
the assembly conditions, this assay exhibited a linear response to
histamine within the range from 70 to 2240 ppm. With excellent stability
and sensitivity, this strip can be used to monitor the quality change
of canned fish at different temperatures, so that people can avoid
suffering from histamine poisoning, suggesting that it holds great
potential in the intelligent system for on-site detection and real-time
monitoring.
A highly selective and sensitive method for Cd(II) detection was developed based on aptamer and gold nanoparticles (AuNPs) combined with a colorimetric smartphone readout. The experimental conditions such as reaction time of polydiene dimethyl ammonium chloride (PDDA) and AuNPs, PDDA dose, time of aptamer and PDDA incubation, and aptamer concentration were optimized. Under the optimized conditions, the color and red(R) value of the solution was concentration-dependent on Cd(II). The proposed method exhibited a linear range of 1–400 ng/mL (r2 = 0.9794) with a limit of detection (LOD) of 1 ng/mL. This method had been successfully applied to test and quantify Cd(II) in water and rice samples, and the results were in full agreement with those from the atomic absorption spectrometer. Therefore, low-cost colorimetry demonstrated its potential for practical application in visual or quantitative detection with a smartphone. This approach can be readily applied to other analytes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.