Evaluation of layered double hydroxide-siRNA composites to investigate structure, binding and gene-silencing activity

Layered double hydroxide (LDH)-based nanomaterials are known for their good biocompatibility, pH-dependent stability, biodegradation properties, anion exchange capacity, easy surface modification, and high chemical stability. More recently, with the rise of oligonucleotide therapeutics and the related delivery challenges, LDHs are emerging as an alternative delivery therapeutic tool for oligonucleotide delivery because of their ability to bind effectively to the negatively charged phosphate backbone of oligonucleotides and release it once it is in the cell. However, based on our knowledge, the potential of using LDHs for short interfering RNA (siRNA) delivery has not been fully explored. In fact, this is the first study of its kind that systematically evaluates several LDHs for siRNA binding, gene silencing, and toxicity. The results of this research reveal that NiAl-NO 3 -LDH/h (h = hydrothermal method) has a comparable gene knockdown to siRNA delivered using common transfection agents such as Lipofectamine 2000™ (Invitrogen), Lipofectamine 3000™ (Invitrogen), and Interferin (ThermoFisher), with gene knockdown of 62.7 %, 62.6 %, 79.3 %, and 78.6 %, respectively. Exploring alternatives to transfection agents is important in driving oligonucleotide therapeutic applications forward because some of them, for example, Lipofectamine 2000™, is well known to exhibit toxicity across various cell lines. • Short interfering RNA delivery to cells remains an ongoing challenge • A comprehensive analysis of the physical properties of several LDH materials and the effect of these properties on short interfering RNA binding, gene silencing and cell toxicity were examined • LDH material NiAl-NO 3 -LDH/h (h = hydrothermal method) produces a potent gene silencing effect of 62 % when complexed with short interfering RNA • All LDH materials synthesized are non-toxic to HeLa and A549 cells