Colloidal Amphiphile Self-Assembly Particles Composed of Gadolinium Oleate and Myverol: Evaluation as Contrast Agents for Magnetic Resonance Imaging

Abstract

Gadolinium oleate has been added at various concentrations to a Myverol inverse bicontinuous cubic phase forming system, and the potential of these systems as magnetic resonance imaging (MRI) contrast agents has been investigated. Differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), and cryo-transmission electron microscopy (cryo-TEM) measurements on the Gd oleate/Myverol systems indicate that Gd oleate is at least partially incorporated within the cubic phase of Myverol. However, at Gd oleate concentrations greater than 1 wt %, partial phase separation of the system may occur with the formation of a Gd-oleate-rich lamellar phase as well as the cubic phase. Bulk Gd oleate/Myverol mixtures can be dispersed into stable colloidal dispersions. SAXS and cryo-TEM measurements on these dispersions indicate that the presence of Gd oleate in the Myverol system prevents the formation of cubosomes from the bulk cubic phase. Instead, the dispersion consists of putative Gd-oleate-rich nonswelling lamellar nanoparticles as well as colloidal particles lacking ordered internal structure. In vitro studies on these dispersions demonstrated that the relaxivity of select Gd oleate/Myverol systems is much higher than that of pure Gd oleate, exemplifying the promise of this system type for magnetic resonance imaging. The highest water proton relaxivities (r(1) = 34.2 mM(-1) s(-1) and r(2) = 27.3 mM(-1) s(-1) at 20 MHz and room temperature) were obtained at a Gd oleate loading concentration of 1 wt %, with a subsequent decrease in relaxivity with increasing Gd oleate concentration. These maximum relaxivities compare favorably with the relaxivities for the commercial contrast agent, Magnevist (r(1) = 4.91 mM(-1) s(-1) and r(2) = 6.26 mM(-1) s(-1) at 20 MHz and room temperature).

Nature‐Inspired Design and Application of Lipidic Lyotropic Liquid Crystals

“…Cubic and inverse hexagonal phases have also been highlighted as a new class of imaging agent . The unique constraints of the internal structure on the mobility of water in the aqueous channels of cubosomes and hexosomes have been shown to provide an enhanced magnetic resonance imaging (MRI) contrast upon loading with nitroxide or heavy metal contrast agents . As seen in Figure , the relaxivity of the mesophase‐hosted material, observed as T1 weighted contrast in the bottom left panel, exceeds that of Magnevist, the gold standard, currently clinically utilized contrast agent.…”

Steric Stabilizers for Cubic Phase Lyotropic Liquid Crystal Nanodispersions (Cubosomes)

“…In other recent developments, cubosomes are also being investigated for the containment of contrast agents for medical imaging applications [106][107][108], and capabilities as a cell-free bio-sensing platform [109]. Apart from drug delivery and biomedical applications, the use and application of lyotropic liquid crystalline nanostructured particles is also relevant within the food industry (e.g., solubilization of food bioactives within lyotropic liquid crystalline mesophases) [110,111] and agriculture industry (e.g., delivery of plant agrochemicals) [112].…”

Nanostructure and cytotoxicity of self-assembled monoolein–capric acid lyotropic liquid crystalline nanoparticles

“…Studies suggested that the packing efficiency of MO molecules results in structures such as an inverse hexagonal phase, several inverse cubic phases, a lamellar phase, and a water-in-oil microemulsion phase (Fig. [27][28][29][30][31] The use of MO based self-assembly objects in drug delivery has gained signicant interest due to its Fig. 4,5 In recent years, an increasing number of studies have focused on MO and its biomedical applications.…”