Efficient siRNA delivery to mammalian cells using layered double hydroxide nanoparticles

Reduction in the size of layered double hydroxide nanoparticles enhances the efficiency of siRNA delivery

“…We observed no significant loss of cell viability across this concentration range. This is consistent with our previous observations that at an L-LDH concentration of up to 500 μg/ml cell viability was found to be greater than 80-90% in various cell lines [12,15,30,31]. As a second measure of cell viability, we investigated the effect of S-LDHs on the ability of HEK 293T cells to proliferate after 48 h exposure ( Figure 3B).…”

“…As previously described, TEM images revealed that synthesis of nanoparticles under aqueous conditions produced L-LDHs with a regular hexagonal shape and the lateral dimension ranging from 100 to 200 nm ( Figure 1A and 1C) [14][15][16]. In contrast, the nonaqueous conditions used to prepare S-LDHs (see Experimental) yielded hexagonally shaped particles with lateral dimensions ranging from 20 to 60 nm ( Figure 1B and 1C).…”

“…LDH nanoparticles are internalized through the clathrin-mediated endocytosis pathway in a range of mammalian cell types, including primary neurons, ensuring efficient release of siRNA-LDH complexes into the cytoplasm where siRNA is then made available to the RISC [8,14,16,18]. Our recent investigations have confirmed the efficacy of LDH-mediated siRNA delivery by markedly reducing the expression of target genes [15,16,19]. It has also been convincingly demonstrated that MgAl-Cl-LDH nanoparticles, due to their simple chemical composition, exhibit lower cytotoxicity and higher biocompatibility when compared to other inorganic and organic nanoparticles [16,20,21].…”

“…In contrast, there was little difference in the XRD patterns of L- 15 LDHs before and after dsDNA loading, implying intercalation of dsDNA/siRNA into the interlayer was minimal [23]. As already discussed in our previous paper [23], the dsDNA loading on L-LDHs was 0.2-0.3 µg (dsDNA)/µg (L-LDHs) at the mass ratio of 1:1, where the dsDNA was largely associated with the LDH particle surface.…”

“…Over recent years clay-based nanoparticles, layered double hydroxides (LDHs), have emerged as a siRNA delivery system with the potential to fulfill the above criteria. LDHs ([Mg n Al(OH) 2n+2 ] + (A -)mH 2 O, where A = Cl -or NO 3 -, n = 2-3, m = 2) have been convincingly shown to efficiently transport a range of anionic drugs, including siRNAs, into mammalian cells [8][9][10][11][12][13][14][15][16]. Structurally, LDHs comprise alternating stacks of positively charged brucite-like layers ([Mg n Al(OH) 2n+2 ] + ), neutralized by exchangeable interlayer hydrated anions ((A -)mH 2 O).…”