Noncanonical Self-Assembly of Multifunctional DNA Nanoflowers for Biomedical Applications

Abstract

DNA nanotechnology has been extensively explored to assemble various functional nanostructures for versatile applications. Mediated by Watson-Crick base-pairing, these DNA nanostructures have been conventionally assembled through hybridization of many short DNA building blocks. Here we report the noncanonical self-assembly of multifunctional DNA nanostructures, termed as nanoflowers (NFs), and the versatile biomedical applications. These NFs were assembled from long DNA building blocks generated via Rolling Circle Replication (RCR) of a designer template. NF assembly was driven by liquid crystallization and dense packaging of building blocks, without relying on Watson-Crick base-pairing between DNA strands, thereby avoiding the otherwise conventional complicated DNA sequence design. NF sizes were readily tunable in a wide range, by simply adjusting such parameters as assembly time and template sequences. NFs were exceptionally resistant to nuclease degradation, denaturation, or dissociation at extremely low concentration, presumably resulting from the dense DNA packaging in NFs. The exceptional biostability is critical for biomedical applications. By rational design, NFs can be readily incorporated with myriad functional moieties. All these properties make NFs promising for versatile applications. As a proof-of-principle demonstration, in this study, NFs were integrated with aptamers, bioimaging agents, and drug loading sites, and the resultant multifunctional NFs were demonstrated for selective cancer cell recognition, bioimaging, and targeted anticancer drug delivery.

Biodegradable, multifunctional DNAzyme nanoflowers for enhanced cancer therapy

“…In addition, they can be endowed with diverse properties, including biorecognition, sensing and imaging, by either hybridizing with complementary oligonucleotides tethered to functional moieties or programming a functional sequence into the DNA chain. [18][19][20][21][22][23] Herein, we present a biodegradable cancer therapeutic system with multiple built-in functions for targeted dual gene silencing and cancer therapy by using a rolling circle amplification (RCA) method (Figure 1). Through the smart design of the template DNA sequence, AS1411 aptamer, an early growth response-1 (EGR-1) DNAzyme, and a survivin DNAzyme were simultaneously incorporated into a self-assembly DNA nanoflower (DNF), which was composed of a long single-stranded DNA (ssDNA) and magnesium pyrophosphate.…”

Self‐Assembled DNA Nanostructures for Drug Delivery

“…[70] DNA nanoflowers (NFs) and nanoclew (NCl) through RCA approach have been proved for traceable targeting, multiplexed intracellular imaging and self-degradable drug delivery. [71][72][73] RCAgenerated periodic DNA nanoribbons (DNRs) are able to work as intracellular pH sensors and efficient small interfering RNA delivery carriers in tumor cells. [74] RCA-based DNA nanostructures provide more choices and enable other programmed drug delivery platforms.…”

Nuclease-resistant synthetic drug-DNA adducts: programmable drug-DNA conjugation for targeted anticancer drug delivery

“…Passive targeting exploits the leaky blood vasculature and poor lymphatic drainage in tumors that allow nanocarriers, such as polymer nanoparticles, 3 liposomes, 7 gold nanoparticles 8 and nucleic acid nanostructures, [9][10][11][12][13][14][15][16][17] to access and accumulate in the tumor by the enhanced permeability and retention effect. 3 DNA, the genetic carrier in nature, has been exploited as both synthetic targeting elements (for example, aptamers, CpG DNA), [18][19][20][21] and nanocarriers [9][10][11][12][13][14][15][16][17] for both active and passive targeted drug delivery, owing to such features as ease of reproducible synthesis and modification, biodegradability, sequence programmability, structure predictability of the resultant DNA drug carriers and intrinsic targeting or therapeutic functionalities. DNA aptamers, screened by Systematic Evolution of Ligands by EXponential enrichment, 22,23 are excellent candidates as targeting elements.…”

“…24 Because of the sequence programmability, DNA has been engineered into various drug nanocarriers. 10,[12][13][14] Moreover, DNA per se can serve as therapeutics, such as DNA antisense, 29 aptamers 24 and immunostimulatory CpG motifs, 21 allowing combination therapy in DNA-based drug delivery systems.…”