A QCM‐D and SAXS Study of the Interaction of Functionalised Lyotropic Liquid Crystalline Lipid Nanoparticles with siRNA

Abstract

Biophysical studies were undertaken to investigate the binding and release of short interfering ribonucleic acid (siRNA) from lyotropic liquid crystalline lipid nanoparticles (LNPs) by using a quartz crystal microbalance (QCM). These carriers are based on phytantriol (Phy) and the cationic lipid DOTAP (1,2-dioleoyloxy-3-(trimethylammonium)propane). The nonlamellar phase LNPs were tethered to the surface of the QCM chip for analysis based on biotin-neutravidin binding, which enabled the controlled deposition of siRNA-LNP complexes with different lipid/siRNA charge ratios on a QCM-D crystal sensor. The binding and release of biomolecules such as siRNA from LNPs was demonstrated to be reliably characterised by this technique. Essential physicochemical parameters of the cationic LNP/siRNA lipoplexes-such as particle size, lyotropic phase behaviour, cytotoxicity, gene silencing and uptake efficiency-were also assessed. The SAXS data show that when the pH was lowered to 5.5 the structure of the lipoplexes did not change, thus indicating that the acidic conditions of the endosome were not a significant factor in the release of siRNA from the cationic lipidic carriers.

Monocytic Cell-Induced Phase Transformation of Circulating Lipid-Based Liquid Crystalline Nanosystems

“…The V2 phase was identified to be of a double diamond (Pn3m) geometry with a peak spacing ratio of √2:√3:√4:√6 (primary peak at q = 0.129 Å −1 ). On the other hand, the vesicular structure (LV) is characterised by a broad, diffuse band, as shown previously by other researchers [24,30,36]. The presence of THP-1 cells was also confirmed to exert negligible interference on the diffraction peak detection.…”

“…As opposed to the existing SAXS profiling of the LLC dispersed systems that typically employed lipid concentrations at > 10 mg/mL, we attempted to identify the lowest possible lipid concentrations that meet both, the SAXS instrument detection limits and the biocompatibility levels 3: √ 4: √ 6 (primary peak at q = 0.129 Å −1 ). On the other hand, the vesicular structure (LV) is characterised by a broad, diffuse band, as shown previously by other researchers [24,30,36]. The presence of THP-1 cells was also confirmed to exert negligible interference on the diffraction peak detection.…”

“…Small angle X-ray scattering (SAXS) analysis, based on the synchrotron source, is a powerful tool to ascertain the phase characteristics of various LLC nanosystems within seconds, as compared to the timeframe of hours on the conventional laboratory SAXS instrument [8,[14][15][16]. It has enabled extensive investigations into the morphological stability and phase transition of LLC systems in water or phosphate buffer saline (PBS) across different environmental and biochemical parameters: Temperature [8,17], hydration state [17,18], ionic strength and biomacromolecule effects [15,[19][20][21][22], as well as pH [23][24][25]. However, their phase behaviour under physiological systemic conditions have been underexplored, to date.…”

Cubosomes: The Next Generation of Smart Lipid Nanoparticles?

“…[118] The inclusion of DOTAP and subsequent loading with nucleic acids can alter the cubosome phase morphology and lead to formation of the hexagonal phase or 'hexosomes' as they are referred to in particulate form. [119,120] There is a review specifically focusing on how nucleic acids can self-organize upon loading into lipid constructs such as cubosomes. [121]…”

Easy colorimetric detection of gadolinium ions based on gold nanoparticles: key role of phosphine-sulfonate ligands

“…23 With a possibility to detect mass changes as low as 1 ng cm À2 , QCM-D was especially used to probe the interaction with macromolecules, such as proteins, nucleic acids, lipid bilayers, bacteria, and polymers. [23][24][25][26][27][28] The studies reporting the adsorption of low molecular weight molecules are more scarce because of measurement difficulties related to low graing density or limited binding affinities. 29 However, the adsorption of uorescein-5isothiocyanate onto gold surfaces passivated either with citrate or with BSPP 30 and the detection of Cu 2+ ions 31 were recently studied through QCM-D sensing experiments.…”