A common anchor facilitated GO-DNA nano-system for multiplex microRNA analysis in live cells

Abstract

The design of a nano-system for the detection of intracellular microRNAs is challenging as it must fulfill complex requirements, i.e., it must have a high sensitivity to determine the dynamic expression level, a good reliability for multiplex and simultaneous detection, and a satisfactory biostability to work in biological environments. Instead of employing a commonly used physisorption or a full-conjugation strategy, here, a GO-DNA nano-system was developed under graft/base-pairing construction. The common anchor sequence was chemically grafted to GO to base-pair with various microRNA probes; and the hybridization with miRNAs drives the dyes on the probes to leave away from GO, resulting in "turned-on" fluorescence. This strategy not only simplifies the synthesis but also efficiently balances the loading yields of different probes. Moreover, the conjugation yield of GO with a base-paired hybrid has been improved by more than two-fold compared to that of the conjugation with a single strand. We demonstrated that base-paired DNA probes could be efficiently delivered into cells along with GO and are properly stabilized by the conjugated anchor sequence. The resultant GO-DNA nano-system exhibited high stability in a complex biological environment and good resistance to nucleases, and was able to accurately discriminate various miRNAs without cross-reaction. With all of these positive features, the GO-DNA nano-system can simultaneously detect three miRNAs and monitor their dynamic expression levels.

Hydrophobic Interaction: A Promising Driving Force for the Biomedical Applications of Nucleic Acids

“…pH-Sensitive GO-DNA nanosensors have been successfully fabricated through combining the chemical conjugation and HSD passivation method, which showed excellent sensing ability not only in vitro but also in intracellular pH detection. [168] Also, by the same strategy, GO-DNA nanosensors for the detection of intracellular microRNAs were fabricated, Figure 16. Label-free biosensors based on the ssDNA-AuNPs complex.…”

Quantum Dot-PNA Conjugates for Target-Catalyzed RNA Detection

“…The QD-based OTR compares favorably to the graphene oxide-DNA platform used for the multiplexed fluorescent detection of RNA reported by Yu et al [141] The latter assay provided the LODs in the range of 136 to 210 pM, depending on the target.…”

Nucleic‐Acid Structures as Intracellular Probes for Live Cells

“…As opposed to physical adsorption of probe sequences onto GO, Yu et al have devised a different strategy for probe association with GO. [223] In particular, they propose a graft/base pairing strategy, whereby amino-labeled strands pre-duplexed with dye-labeled recognition sequences are covalently attached to the GO surface. In the fluorescence off state, dye-labeled strands are flexible and thus near the GO surface, leading to fluorescence quenching.…”