A label-free kissing complex-induced fluorescence sensor for DNA and RNA detection by using DNA-templated silver nanoclusters as a signal transducer

RSC Advances ◽  
2016 ◽  
Vol 6 (101) ◽  
pp. 99269-99273 ◽  
Author(s):  
Kai Zhang ◽  
Ke Wang ◽  
Xue Zhu ◽  
Minhao Xie ◽  
Fei Xu

A new strategy integrate silver nanoclusters (AgNCs) and riboswitches for the expanding of the application of a kissing complexes-induced sensor (KCIS) for the assay of DNA and RNA was reported.

Author(s):  
Hengchao Li ◽  
Bin Hu ◽  
Yuliang Cheng ◽  
Hang Yu ◽  
Yunfei Xie ◽  
...  

In this presented work, a facile and efficient method was established for the detection of chloramphenicol (CAP) based on target-induced structure transformation of aptamer. This aptamer DNA with a hairpin structure can coincidentally serve as a template for the synthesis of bright silver nanoclusters (quantum yield 16.36%). The binding of CAP with aptamer DNA could cause the destruction of the hairpin structure, resulting in the quenching of the fluorescence of silver nanoclusters (AgNCs). It costs less than 10 minutes to complete the assay, and excellent sensitivity was achieved with detection limit of 0.052 nmol/L. The selectivity and recovery experiments also demonstrated satisfactory results of this proposed protocol. The method has potential applicability, and provides a new strategy for the development of label-free sensors based on aptamer and AgNCs.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Nils Kosiol ◽  
Stefan Juranek ◽  
Peter Brossart ◽  
Annkristin Heine ◽  
Katrin Paeschke

AbstractDNA and RNA can fold into a variety of alternative conformations. In recent years, a particular nucleic acid structure was discussed to play a role in malignant transformation and cancer development. This structure is called a G-quadruplex (G4). G4 structure formation can drive genome instability by creating mutations, deletions and stimulating recombination events. The importance of G4 structures in the characterization of malignant cells was currently demonstrated in breast cancer samples. In this analysis a correlation between G4 structure formation and an increased intratumor heterogeneity was identified. This suggests that G4 structures might allow breast cancer stratification and supports the identification of new personalized treatment options. Because of the stability of G4 structures and their presence within most human oncogenic promoters and at telomeres, G4 structures are currently tested as a therapeutic target to downregulate transcription or to block telomere elongation in cancer cells. To date, different chemical molecules (G4 ligands) have been developed that aim to target G4 structures. In this review we discuss and compare G4 function and relevance for therapeutic approaches and their impact on cancer development for three cancer entities, which differ significantly in their amount and type of mutations: pancreatic cancer, leukemia and malignant melanoma. G4 structures might present a promising new strategy to individually target tumor cells and could support personalized treatment approaches in the future.


RSC Advances ◽  
2016 ◽  
Vol 6 (62) ◽  
pp. 57502-57506 ◽  
Author(s):  
Lin Liu ◽  
Qing Li ◽  
Li-Juan Tang ◽  
Ru-Qin Yu ◽  
Jian-Hui Jiang

A hybridization chain reaction (HCR) lightened by DNA-stabilized silver nanoclusters (AgNCs) as a label-free and turn on fluorescence platform for nucleic acid assays.


2014 ◽  
Vol 6 (15) ◽  
pp. 6082-6087 ◽  
Author(s):  
Hui Ma ◽  
Wei Wei ◽  
Qian Lu ◽  
Zhixin Zhou ◽  
Henan Li ◽  
...  

A label-free DNA biosensor with high sensitivity and selectivity is constructed by using DNA–Ag NCs and Exo III-catalyzed target recycling amplification.


Biosensors ◽  
2013 ◽  
Vol 3 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Judy Obliosca ◽  
Cong Liu ◽  
Robert Batson ◽  
Mark Babin ◽  
James Werner ◽  
...  

2016 ◽  
Vol 27 (2) ◽  
pp. 643-649 ◽  
Author(s):  
Xiao-Yu Wang ◽  
Cheng-Gang Niu ◽  
Li-Juan Guo ◽  
Liu-Yin Hu ◽  
Sheng-Quan Wu ◽  
...  

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1213 ◽  
Author(s):  
Miguel Moreno ◽  
María Fernández-Algar ◽  
Javier Fernández-Chamorro ◽  
Jorge Ramajo ◽  
Encarnación Martínez-Salas ◽  
...  

Improvements in Systematic Evolution of Ligands by EXponential enrichment (SELEX) technology and DNA sequencing methods have led to the identification of a large number of active nucleic acid molecules after any aptamer selection experiment. As a result, the search for the fittest aptamers has become a laborious and time-consuming task. Herein, we present an optimized approach for the label-free characterization of DNA and RNA aptamers in parallel. The developed method consists in an Enzyme-Linked OligoNucleotide Assay (ELONA) coupled to either real-time quantitative PCR (qPCR, for DNA aptamers) or reverse transcription qPCR (RTqPCR, for RNA aptamers), which allows the detection of aptamer-target interactions in the high femtomolar range. We have applied this methodology to the affinity analysis of DNA and RNA aptamers selected against the poly(C)-binding protein 2 (PCBP-2). In addition, we have used ELONA-(RT)qPCR to quantify the dissociation constant (Kd) and maximum binding capacity (Bmax) of 16 high affinity DNA and RNA aptamers. The Kd values of the high affinity DNA aptamers were compared to those derived from colorimetric ELONA performed in parallel. Additionally, Electrophoretic Mobility Shift Assays (EMSA) were used to confirm the binding of representative PCBP-2-specific RNA aptamers in solution. We propose this ELONA-(RT)qPCR approach as a general strategy for aptamer characterization, with a broad applicability in biotechnology and biomedicine.


Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 129
Author(s):  
Ivo Crnolatac ◽  
Letícia Giestas ◽  
Gordan Horvat ◽  
António Jorge Parola ◽  
Ivo Piantanida

The interaction of 4′-(N,N-dimethylamino)-6-hydroxyflavylium cation with double stranded (ds-) DNA/RNA was studied by UV/Vis spectrophotometry, circular dichroism (CD), and also steady-state and time-resolved emission spectroscopies at neutral and weakly acidic conditions. At pH 5, the studied molecule, in its flavylium cationic form, showed considerable binding affinities (5 < logKs < 6) for all ds-DNA/RNA, contrary to chalcones forms (dominant at pH 7), which did not show binding to polynucleotides. Flavylium cation intercalated into ds-DNAs at variance to dominant groove aggregation within ds-RNA, which was reported by RNA-specific bisignate induced CD spectrum (ICD) bands. The intrinsically negligible fluorescence of flavylium was strongly increased upon the addition of DNA or RNA, whereby both the fluorescence intensity and emission lifetimes of complexes differed considerably: the strongest emission increase was observed for AU-RNA (detection limit estimated to 10 nM) followed by AT-DNAs and the much weaker effect of GC-DNAs. Both fluorescence sensitivity on the ds-DNA/RNA secondary structure and sequence-selective ICD bands make the flavylium–chalcones system an intriguing pH-switchable new probe for distinguishing between various polynucleotide sequences.


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