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  • Oligonucleotide sensor based on magnetic capture and photoligation of upconverting nanoparticles in solid surfaces.

Oligonucleotide sensor based on magnetic capture and photoligation of upconverting nanoparticles in solid surfaces.

Journal of colloid and interface science (2021-04-11)
Diego Mendez-Gonzalez, Pedro P Silva-Ibáñez, Fernando Valiente-Dies, Oscar G Calderón, Juan L Mendez-Gonzalez, Marco Laurenti, Ana Egatz-Gómez, Elena Díaz, Jorge Rubio-Retama, Sonia Melle
ABSTRACT

In this work, we present a luminescence platform that can be used as point of care system for determining the presence and concentration of specific oligonucleotide sequences. This sensor exhibited a limit of detection as low as 50 fM by means of: (i) the use of single-stranded DNA (ssDNA) functionalized magnetic microparticles that captured and concentrated ssDNA-upconverting nanoparticles (ssDNA-UCNPs) on a solid support, when the target sequence (miR-21-5p DNA-analogue) was in the sample, and (ii) a photoligation reaction that covalently linked the ssDNA-UCNPs and the ssDNA magnetic microparticles, allowing stringent washes. The presented sensor showed a similar limit of detection when the assays were conducted in samples containing total miRNA extracted from human serum, demonstrating its suitability for detecting small specific oligonucleotide sequences under real-like conditions. The strategy of combining UCNPs, magnetic microparticles, and a photoligation reaction provides new insight into low-cost, rapid, and ultra-sensitive detection of oligonucleotide sequences.

MATERIALS
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