A Fluorescence Light-Up Ag Nanocluster Probe That Discriminates Single-Nucleotide Variants by Emission Color

Abstract

Rapid and precise screening of small genetic variations, such as single-nucleotide polymorphisms (SNPs), among an individual’s genome is still an unmet challenge at point-of-care settings. One crucial step towards this goal is the development of discrimination probes that require no enzymatic reaction and are easy to use. Here we report a new type of fluorescent molecular probe, termed a chameleon NanoCluster Beacon (cNCB), that lights up into different colors upon binding SNP targets. NanoCluster Beacons (NCBs) are collections of a small number of Ag atoms templated on single-stranded DNA that fluoresce strongly when placed in proximity to particular DNA sequences, termed enhancers. Here we show the fluorescence emission color of a NCB can change substantially (a shift of 60–70 nm in the emission maximum) depending upon the alignment between the silver nanocluster and the DNA enhancer sequence. Chameleon NCBs exploit this color shift to directly detect SNPs, based on the fact that different SNPs produce a different alignment between the Ag nanocluster and the enhancer. This SNP detection method has been validated on all single-nucleotide substitution scenarios in three synthetic DNA targets, in six disease-related SNP targets, and in two clinical samples taken from patients with ovarian serous borderline tumors. Samples with single-nucleotide variations can be easily identified by the naked eye under UV excitation, making this method a reliable and low-cost assay with a simple readout format.

DNA-stabilized, fluorescent, metal nanoclusters for biosensor development

“…In a follow-up work, the authors further optimized the DNA sequences and demonstrated that a single mutation in the target sequence can result in a large emission wavelength shift [103].…”

DNA-templated fluorescent gold nanoclusters reduced by Good’s buffer: from blue-emitting seeds to red and near infrared emitters

“…[18][19][20][21][22][23][24][25] Amongst these stabilizers, DNA is very attractive due to its excellent programmability, stability and cost-effectiveness. [26][27][28][29][30] Taking advantage of the strong binding interaction between cytosine and Ag + , a wide range of emission colors are obtained by using various cytosine-rich DNA sequences, [12][13][14][15][16][17]31,32 where NaBH4 has been the exclusively used reducing agent.…”

Correlation of photobleaching, oxidation and metal induced fluorescence quenching of DNA-templated silver nanoclusters

“…[19][20][21][22][23] On the practical side, by rational incorporation of DNA aptamers, the fluorescence signaling of AgNCs has been successfully coupled with the molecular recognition property of DNA to design biosensors and smart imaging probes. [24][25][26][27][28][29][30][31][32][33][34][35][36] An interesting and useful discovery is that the fluorescence of many NCs is strongly quenched by Hg 2+ , allowing its detection at low nM and even sub-nM concentrations. 20,[37][38][39][40][41][42] Despite its importance in analytical chemistry, our fundamental understanding of NCs is still quite limited.…”