The presence of a single-nucleotide mismatch in linker increases the fluorescence of guanine-enhanced DNA-templated Ag nanoclusters and their application for highly sensitive detection of cyanide

Abstract

Fluorescence of DNA-templated silver nanoclusters can be enhanced by more than 100-fold by placing the nanoclusters in proximity to guanine-rich DNA sequences after hybridization. We found that the fluorescence of the guanine-enhanced silver nanoclusters is not increased with the guanine-rich DNA sequence closer to the silver nanoclusters. By studying the different numbers of mismatches in the linker sequences, we found that the presence of a single-nucleotide mismatch in the linker increases fluorescence more than the complementary nucleotide. Further study indicated the mismatch position of the linker sequence also affects the fluorescence of the hybridized DNA-Ag NCs. The evidence reported here indicated that the mismatch of the linker sequence affects the fluorescence enhancement of guanine-enhanced silver nanoclusters. We also found that DNA-Ag NCs is an excellent fluorescence sensor for cyanide, as cyanide effectively quenches the fluorescence of NCs at a very low concentration with high selectivity. Cyanide in the range from 0.10 mM to 0.35 mM could be linearly detected, with a detection limit of 25.6 nM.

An Overview on Coinage Metal Nanocluster-Based Luminescent Biosensors via Etching Chemistry

“…This sensor saved time and was more sensitive than previous chemical sensors that detected CN − [ 139 , 140 , 141 ]. In addition, the preparation of sensors based on cyanide etched clusters was also reported by other groups [ 97 , 98 , 99 , 142 , 143 ].…”

“…Likewise, CN − also has the ability to etch metal NCs. For example, Peng et al [97] found that CN − could be used to etch Ag NCs, and Shamsipur et al [98] found that CN − could also etch Au NCs. Tian et al [39] found that CN − was able to etch bimetallic gold-silver CN − into this cluster is as follows: In addition, some research groups pointed out that the etching phenomenon caused by thiol was affected by pH.…”

Ultrasensitive Monitoring of Cyanide Concentrations in Water Using a Aucore–Agshell Hybrid-Coating-Based Fiber Optical Sensor

“…Most organic fluorophores are toxic and are only soluble in organic solvents, thus causing limitations in the manufacturing process and practical applications . To overcome this limitation, metal nanoparticles have been used as fluorescence-based chemosensors but have not achieved high sensitivity efficiency …”

Application of optical hydrogels in environmental sensing

“…Therefore, PT-DNA-based BFHs combined with tyrosinase enabled pesticide detection [119] . Based on similar mechanisms, higher-cost DNA-templated fluorescent Au NCs [120] and Ag NCs [121] could also detect different pollutants.…”