Filtern
Dokumenttyp
Sprache
- Englisch (2)
Schlagworte
- Assay (1)
- Click chemistry (1)
- DNA (1)
- FRET (1)
- Fluorescence (1)
- Ligation Assay (1)
- Nano (1)
- PNA (1)
- Particle (1)
- QD (1)
Organisationseinheit der BAM
Detection of pathogenic nucleic acids remains one of the most reliable approaches for the diagnosis of a broad range of diseases. Current PCR-based methods require experienced personnel and cannot be easily used for point-of care diagnostics, making alternative strategies for the sensitive, reliable, and cost-efficient detection of pathogenic nucleic acids highly desirable. Here, we report an enzyme-free method for the fluorometric detection of RNA that relies on a target-induced fluorophore transfer onto a semiconductor quantum dot (QD), uses PNA probes as selective recognition elements and can be read out with simple and inexpensive equipment. For QD-PNA conjugates with optimized PNA content, limits of detection of dengue RNA in the range of 10 pM to 100 nM can be realized within 5 h in the presence of a high excess of noncomplementary RNA.
Today, 40 % of the world’s population live in areas with a significant risk of dengue infection. Early and reliable diagnosis of dengue virus (DENV) is essential to provide the patients with the required medical care and prevent spreading of the disease. Conventional methods for DENV diagnosis like PCR and virus isolation can be used in laboratory settings, yet are difficult to implement in point-of-care diagnostics, requiring simple, selective, fast, and sensitive detection schemes. We present here a novel approach for the detection of DENV, via its RNA, with optical read-out that relies on RNA-catalyzed fluorophore transfer onto a semiconductor quantum dot (QD) and Förster resonance energy transfer (FRET).
For this RNA assay, peptide nucleic acid (PNA) oligomers were used as highly specific capture and reporter probes. PNA exhibits remarkable affinity towards RNA as well as extremely high chemical and enzymatic stability. The capture probe, which is immobilized on a QD acting as FRET donor, bears a nucleophile at the N-terminus and the reporter probe is modified with an organic dye acting as FRET acceptor. The presence of DENV genomic RNA in the sample triggers a transfer of the dye onto the QD, signaled by FRET between the QD and the dye. A unique advantage of this system is the ability of one RNA molecule to trigger multiple transfer reactions, thereby amplifying the fluorescence signal. This assay together with the exceptional brightness of QDs and outstanding hybridization properties of PNA allows for highly specific and sensitive detection of DENV RNA in the sub-nM range.