Hairpin-like siRNA-Based Spherical Nucleic Acids

Abstract

The therapeutic use of small interfering RNAs (siRNAs) as gene regulation agents has been limited by their poor stability and delivery. Although arranging siRNAs into a spherical nucleic acid (SNA) architecture to form siRNA-SNAs increases their stability and uptake, prototypical siRNA-SNAs consist of a hybridized architecture that causes guide strand dissociation from passenger strands, which limits the delivery of active siRNA duplexes. In this study, a new SNA design that directly attaches both siRNA strands to the SNA core through a single hairpin-shaped molecule to prevent guide strand dissociation is introduced and investigated. This hairpin-like architecture increases the number of siRNA duplexes that can be loaded onto an SNA by 4-fold compared to the original hybridized siRNA-SNA architecture. As a result, the hairpin-like siRNA-SNAs exhibit a 6-fold longer half-life in serum and decreased cytotoxicity. In addition, the hairpin-like siRNA-SNA produces more durable gene knockdown than the hybridized siRNA-SNA. This study shows how the chemistry used to immobilize siRNA on nanoparticles can markedly enhance biological function, and it establishes the hairpin-like architecture as a next-generation SNA construct that will be useful in life science and medical research.

Multiplexed Organelles Portrait Barcodes for Subcellular MicroRNA Array Detection in Living Cells

“…Dynamic light scattering (DLS) and Zeta potential analysis showed a minimal change of MOPB in cell lysis buffer for 2 days, and there was no significant change in FL during 24 h, indicating the excellent stability of MOPB (Figure S4). Good stability could come from the widely reported spherical nucleic acid structure’s protection effect. − …”

Spherical Nucleic Acids as Precision Therapeutics for the Treatment of Cancer—From Bench to Bedside

“…A recent study exemplified the need to further optimize gene-regulatory SNAs. Vasher et al [ 90 ] developed a novel SNA architecture in which both strands of a hairpin-like siRNA oligonucleotide were attached to the gold core template to prevent guide strand dissociation from the passenger strand. Such strand dissociation is typically observed with first-generation SNAs, in which the passenger strand is attached to the gold core via thiol adsorption, and the guide strand is linked to the passenger strand via complementary base pair hybridization.…”

“…Such strand dissociation is typically observed with first-generation SNAs, in which the passenger strand is attached to the gold core via thiol adsorption, and the guide strand is linked to the passenger strand via complementary base pair hybridization. This next-generation gene-regulatory SNA construct achieved higher loading and increased the delivery of active siRNA duplexes, longer siRNA half-life, and more durable gene knockdown [ 90 ]. Another design parameter to consider is the presence of guanine-rich sequence motifs.…”

Nucleic acid-based artificial nanocarriers for gene therapy

“…64 Subsequently, the remaining antisense strand in the RISC hybridizes with its complementary messenger RNA (mRNA) to prevent translation and selectively silence the target gene expression. 65,66 In order to exhibit its effect, siRNA needs to be delivered into the cytoplasm of the target cell. DNA nanostructures can be easily designed as vectors to carry siRNAs through DNA/RNA hybridization, providing a novel platform for siRNA delivery.…”