Oligothiophene molecular beacons

Rolling Circle Amplification-Based Polyvalent Molecular Beacon Probe-Assisted Signal Amplification Strategies for Sensitive Detection of B16 Cells

We developed a simple and sensitive signal amplification method for the detection of B16 cells based on the combination of rolling circle amplification (RCA) and molecular beacons (MBs). A long-chain structure of DNA synthesized by RCA was used to turn on aptamer-based MBs. Because of the multiple complementary repeat units, the RCA scaffold hybridized tens or hundreds of MBs to form polyvalent aptamer probes. The unfold ability and the fluorescence intensity of MBs were both improved by RCA, as compared to short single chains. The cell experiment results demonstrated that RCA-based polyvalent MBs were significantly more effective than monovalent MBs in targeting B16 cells and signal sensitivity because of their multivalent effects. The establishment of this strategy would provide a powerful platform for early clinical diagnostics of cancer cells.

Labeling deoxyadenosine for the preparation of functional conjugated oligonucleotides

Herein we present a versatile synthetic method for the 8-thioalkylation of (deoxy)adenosine with a short carbon linker having on the other side a variety of molecules (psoralen, acridine) and functional groups (alkyne). After conventional protections, the modified adenosine can be phosphytylated and inserted into an oligonucleotide without affecting the standard protocols for supported oligonucleotide synthesis. The hybridization properties of a generic oligonucleotide containing the above conjugated moieties toward both DNA and RNA are evaluated both in the case of a perfectly complementary strand and in the case of a single mismatch. This methodology is suitable for the preparation of several types of derivatives and—through the alkynyl moiety—provides fast access to click-chemistry transformations.

Oligothiophene-5-labeled deoxyuridines for the detection of single nucleotide polymorphisms

We report the synthesis of four oligothiophene-5-labeled deoxyuridines. These modified fluorescent nucleosides have been incorporated into oligodeoxynucleotides designed to be used as probes to discriminate, through changes in fluorescence emission, between hybridization with a perfectly complementary strand and that with a single nucleotide mismatch facing the modified uridines. Upon hybridization, remarkable differences (up to 47%) of the emitted light, depending on the uridine facing base, were observed.