A multi-color fluorescent sensing system integrated with color recognition, liquid crystal display, and voice output module for intelligent detection of two targets

Both tetracycline antibiotics (TC) and Bacillus anthracis are highly resistant to extreme environments. However, there are few studies on the intelligence detection of these two substances by establishing different detection channels. In this research, dual rare-earth coordination polymers were prepared for the detection of Bacillus anthracis and tetracycline. As a unique biomarker of B. anthracis, 2,6-pyridine dicarboxylic acid (DPA) can enhance the green fluorescence emission of Tb3+, achieving a fluorescence change from red to yellowish-green under 282 nm excitation light. Under the excitation light of 395 nm, the TC can coordinate to Eu3+ and sensitize Eu3+ to emit light through the “antenna effect,” thus achieving the fluorescence change from colorless to red. To validate the protocol's applicability in environmental samples, we detected tetracycline and Bacillus anthracis in milk, honey, and tap water. In addition, quick sensing of Bacillus anthracis in soil and tetracycline on the surface of fruits was also achieved by glove-based portable sensors. Furthermore, combined with the color recognition, liquid crystal display, and intelligent voice output system in 51 microcontrollers, it can realize the intelligent and instantaneous detection of various target molecules in real life, which had a wide range of application value and prospects.