A DNA sensor based on upconversion nanoparticles and two-dimensional dichalcogenide materials

We demonstrate the fabrication of a new DNA sensor that is based on the optical interactions occurring between oligonucleotide-coated NaYF 4:Yb 3+;Er 3+ upconversion nanoparticles and the two-dimensional dichalcogenide materials, MoS 2 and WS 2. Monodisperse upconversion nanoparticles were functionalized with single-stranded DNA endowing the nanoparticles with the ability to interact with the surface of the two-dimensional materials via van der Waals interactions leading to subsequent quenching of the upconversion fluorescence. By contrast, in the presence of a complementary oligonucleotide target and the formation of double-stranded DNA, the upconversion nanoparticles could not interact with MoS 2 and WS 2, thus retaining their inherent fluorescence properties. Utilizing this sensor we were able to detect target oligonucleotides with high sensitivity and specificity whilst reaching a concentration detection limit as low as 5 mol·L −1, within minutes. [Figure not available: see fulltext.]