High-Discrimination Factor Nanosensor Based on Tetrahedral DNA Nanostructures and Gold Nanoparticles for Detection of MiRNA-21 in Live Cells

Abstract

While detection of microRNA with or without signal amplification is highly informative, nanosensors with high specificity for cell-specific RNA detection are rare.Methods: In this study, a tetrahedral DNA nanostructure (TDN) with a specific function was combined with gold nanoparticles (Au-NP) possessing fluorescence quenching effects and a large surface area to fabricate a fluorescence resonance energy transfer based nanosensor (Au-TDNN). The presence of miR-21 (target) can separate the fluorescent dye-labeled detection probe on Au-TDNNs from Au-NPs, which separates the donor and acceptor, thus inducing an intensive fluorescence signal. High specificity for discerning point mutation targets was achieved by rationally designing the nucleic acid strand displacement reaction to occur spontaneously with ΔG0 ≈ 0 based on thermodynamic parameters; under this condition, slight thermodynamic changes caused by base mismatch exert significant effects on hybridization yield.Results: Chemically synthesized DNA of three single-base-changed analogues of target, let-7d, and miR-200b were tested. A discrimination factor (DF) of 15.4 was produced by the expected detection probe on Au-NPs for proximal single-base mismatch. As the control group, the DF produced by an ordinary detection probe on Au-NPs only reached 2.4. The feasibility of the proposed strategy was also confirmed using hepatocyte cancer cells (HepG2).Conclusion: This improved nanosensor opens a new avenue for the specific and easy detection of microRNA in live cells.

DNA nanotechnology approaches for microRNA detection and diagnosis

“…This process releases the target microRNA to enable several reaction cycles resulting in more fluorophore release. Xie and co-workers designed fluorescent DNA probes attached to gold nanoparticles, additionally using DNA tetrahedra to control the probe surface density (116). Target microRNA binds and releases the fluorophore-containing strand in the duplex, releasing it from the quenching nanoparticle and increasing fluorescence.…”

A nanoprobe for fluorescent monitoring of microRNA and targeted delivery of drugs

“… 6 Our team previously presented real-time detection of microRNA-21 (miR-21) in HepG2 cells, by utilizing a 6-carboxy-fluorescein (6-FAM) labeled DNA tetrahedral modified AuNPs fluorescent probe. 7 However, ultraviolet (UV) or visible light-excited fluorescence signals are confronted with drawbacks like slight penetration depth, photodamage and interference of auto-fluorescence. Considerable research shows that near-infrared nanomaterials excited by long-wavelength light have obvious advantages in bioanalysis.…”

An Intelligent DNA Nanorobot with in Vitro Enhanced Protein Lysosomal Degradation of HER2

“…33−39 In particular, many studies reported that a tetrahedral framework nucleic acid (tFNA) could serve as a promising DNA nanocarrier for many antitumor drugs, owing to its high biocompatibility and biosecurity. 40−42 For example, tFNA was reported to effectively deliver paclitaxel or doxorubicin to cancer cells for reversing drug resistance, 41,42 small interfering RNAs (siRNAs) have been modified into tFNA for targeted drug delivery, 43,44 and tFNA could deliver antisense peptide nucleic acids to inhibit methicillin-resistant Staphylococcus aureus. 45 Moreover, the production and storage of tFNA are not complicated, and they can be quickly degraded in lysosomes by cells.…”

“…DNA origami is an emerging field of DNA-based nanotechnology, − and intelligent DNA nanorobots show great promise in working as a drug delivery system in healthcare. − Different DNA-based nanorobots have been developed as affordable and facile therapeutic drugs. − In particular, many studies reported that a tetrahedral framework nucleic acid (tFNA) could serve as a promising DNA nanocarrier for many antitumor drugs, owing to its high biocompatibility and biosecurity. − For example, tFNA was reported to effectively deliver paclitaxel or doxorubicin to cancer cells for reversing drug resistance, , small interfering RNAs (siRNAs) have been modified into tFNA for targeted drug delivery, , and tFNA could deliver antisense peptide nucleic acids to inhibit methicillin-resistant Staphylococcus aureus . Moreover, the production and storage of tFNA are not complicated, and they can be quickly degraded in lysosomes by cells. , Since both free HApt and tFNA can be diverted into lysosomes, we hypothesized that combining the HApt and tFNA as a novel DNA nanorobot (namely, HApt-tFNA) would be an effective strategy to improve its delivery and therapeutic efficacy in treating HER2-positive breast cancer.…”

“…Meanwhile, we suspect that tFNA modified with different valence numbers of HApt might be able to enhance the anticancer effect on HER2-positive cancer cells. As mentioned above, tFNA can also be modified with various materials to perform specific functions. − Therefore, the tFNA nanorobot can also be loaded with other materials such as siRNA to regulate or silence the expression of certain genes to amplify the effects against HER2-postive cancer cells . Moreover, the better stability, longer circulation time, and half-time of HApt-tFNA than free HApt might improve the anticancer effects by prolonging the action time after targeting HER2.…”