Photocaged Nanoparticle Sensor for Sensitive MicroRNA Imaging in Living Cancer Cells with Temporal Control

Abstract

Sensitive imaging of microRNA in living cells is of great value for disease diagnostics and prognostics. While signal amplification-based strategies have been developed for imaging low-abundance disease-relevant microRNA molecules, precise temporal control over sensor activity in living cells still remains a challenge, and limits their applications for sensing microRNA concentration dynamics. Herein, we report a class of photocaged nanoparticle sensors for highly sensitive imaging of microRNA in living cells with temporal control. The sensor features a DNA-templated gold nanoparticle-quantum dot satellite nanostructure which is temporarily inactivated by a photocaged DNA mask. Upon UV light irradiation, the sensor restores its activity for catalytic sensing of microRNA in living cells via entropy-driven two-step toehold-mediated strand displacement reactions. We show that the sensor exhibits quick response to UV light, robust intracellular stability, and high specificity and sensitivity for the microRNA target. On the basis of this strategy, precise control over sensor activity is achieved using an external light trigger, where on-demand sensing could be potentially performed with spatiotemporal control.

Principles and Applications of Nucleic Acid Strand Displacement Reactions

“…In another approach, RNA target molecules were used to trigger the formation of a Au-NP containing DNA network for colorimetric readout, which facilitated differentation between the 16S rRNAs of closely related bacteria with a detection limit of ≥5 × 10 5 CFU . Similar as for the HCR and CHA discussed above, also a large number of miRNA sensors have been developed (Figure ), which utilize strand displacement reactions in their sensing scheme, achieving detection of miRNA from the nanomolar down to the femtomolar range. ,− Of note, Zhang et al achieved detection of miRNA at a concentration of 67 aM using a DNA walker scheme, and Shen et al also used strand displacement techniques for sensitive miRNA imaging …”

Fuel‐Powered DNA Nanomachines for Biosensing and Cancer Therapy

“…Subsequently, to precise and on-demand detection of miRNA, a photocaged nanoparticle sensor based on the above mechanism was constructed by their groups using UV light as an external stimulus to precisely control over the activity of sensors for sensing of miRNA with spatiotemporal control. [27] Inspired by the design of entropy-driven catalytic (EDC) amplification reaction, Liang and co-workers established a three-dimensional, entropy-driven DNA nanomachine based on gold nanoparticles for miRNA amplification detection inside living cells (Figure 1B). [28] This DNA nanomachine is composed of a three-stranded complex (A/B/C) that acts as a DNA track and an entropy-catalytic substrate, a ligand (L) strand, a walking leg (W) and a fuel (F), in which L could be used as a foothold of W via binding to miRNA (T).…”

Nucleic‐Acid Structures as Intracellular Probes for Live Cells

“…An amplification element was also introduced by incorporating a fuel strand that displaces the target, therefore allowing the target to bind to multiple recognition strands. Shen et al have used the same strategy, but have made their sensor start functioning “on demand” by pre‐functionalizing the entire recognition strand with DNA so as to not allow target binding initially . One of the strands functionalized to the recognition strand contains a photocleavable linker that is cleaved after UV radiation, thus partially exposing the recognition strand and yielding the same system as He et al…”