CRISPR/Cas12a-Assisted Visual Logic-Gate Detection of Pathogenic Microorganisms Based on Water-Soluble DNA-Binding AIEgens

Here, we developed a rapid, visual and double-checked Logic Gate detection platform for detection of pathogenic microorganisms by aggregation-induced emission luminogens (AIEgens) in combination with Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR associated (Cas). DNA light-up AIEgens (1,1,2,2-tetrakis[4-(2-bromo-ethoxy) phenyl]ethene, TTAPE) was non-emissive but the emission was turned on in the presence of large amount of DNA produced by recombinase polymerase amplification (RPA). When CRISPR/Cas12a was added, all long-stranded DNA were cut leading to the emission quenched. Thus, a method that can directly observe the emission changes with the naked eye has been successfully constructed. The detection is speedy within only 20 min, and has strong specificity to the target. The result can be judged by Logic Gate. Only when the output signal is (1,0), does it represent the presence of pathogenic microorganisms in the test object. Finally, the method was applied to the detect pathogenic microorganisms in environmental water samples, which proved that this method has high selectivity, specificity and applicability for the detection of pathogenic microorganisms in environmental water samples.

Electrochemical detection of Cd(ii) ions in complex matrices with nanopipets

A nanopipet electrochemical sensor was successfully utilized to detect free Cd(ll) ions in complicated matrices and real environmental water samples.

Cost-Effective Tween 80-Capped Copper Nanoparticles for Ultrasensitive Colorimetric Detection of Thiram Pesticide in Environmental Water Samples

Thiram plays a critical role in protecting fruits and vegetables from damage by various crop diseases, but its residues significantly affect the environment, such as soil and water pollution, and becoming a serious threat to human health. Herein, Tween 80-capped copper nanoparticles (Tween 80-CuNPs) were developed as a convenient and low-cost colorimetric probe for selective detection of thiram pesticide. In the presence of thiram, the color of Tween 80-capped CuNPs changed from dark brown to olive green and colorless at high thiram concentrations. The Tween 80-capped CuNPs-based colorimetric probe exhibited good selectivity and high sensitivity (LOD about 0.17 μM) with a high linearity level in the calibration range of 0.5–25 μM of thiram concentrations. The thiram limit of detection (LOD) of proposed sensor is lower than the maximum residue limit (MRL) regulated by the governments of EU and Vietnam. Moreover, the proposed sensor was successfully applied to determine thiram in tap water with percentage recovery of 98-107% and high repeatability ( RSD = 1.9 % ). The obtained results indicated that Tween 80-capped CuNPs would become a cost-effective sensing platform for ultrahigh-sensitive thiram determination in the environmental water samples.