Preparation of fluorescent DNA probe by solid-phase organic synthesis

Abstract

Abstract. Fluorescent DNA probe based on fluorescence resonance energy transfer (FRET) was prepared by solid-phase organic synthesis when CdTe quantum dots (QDs) were as energy donors and Au nanoparticles (AuNPs) were as energy accepters. The poly(divinylbenzene) core/poly(4-vinylpyridine) shell microspheres, as solid-phase carriers, were prepared by seeds distillation-precipitation polymerization with 2,2′-azobisisobutyronitrile (AIBN) as initiator in neat acetonitrile. The CdTe QDs and AuNPs were self-assembled on the surface of core/shell microspheres, and then the linkage of CdTe QDs with oligonucleotides (CdTe-DNA) and AuNPs with complementary single-stranded DNA (Au-DNA) was on the solid-phase carriers instead of in aqueous solution. The hybridization of complementary double stranded DNA (dsDNA) bonded to the QDs and AuNPs (CdTe-dsDNA-Au) determined the FRET distance of CdTe QDs and AuNPs. Compared with the fluorescence of CdTe-DNA, the fluorescence of CdTe-dsDNA-Au conjugates (DNA probes) decreased extremely, which indicated that the FRET occurred between CdTe QDs and AuNPs. The probe system would have a certain degree recovery of fluorescence when the complementary single stranded DNA was introduced into this system, which showed that the distance between CdTe QDs and AuNPs was increased.

Fluorescent DNA Biosensors on Silica Microspheres

“…Gold nanoparticles (AuNPs) have high extinction coefficient and broad absorption spectrum in visible light. Recently, complex nanostructures formed by linking QDs as energy donors and AuNPs as energy acceptors through DNA hybridization have also been realized [5][6]. In this work, a fluorescent DNA biosensor system based on microspheres carried DNA probe was presented, it was shown in Fig.…”