Preparation and characterization of extruded magnetoliposomes

Sabaté, Raimon; Barnadas‐Rodríguez, Ramon; Callejas-Fernández, J.; Hidalgo‐Álvarez, R.; Estelrich, Joan

doi:10.1016/j.ijpharm.2007.06.047

Cited by 81 publications

(52 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Additionally, we observed the highest encapsulation efficiency of 92% for the sample with the lowest initial iron concentration of 0.5 mg Fe/mL. This is in agreement with the results obtained by Sabaté et al, 10 who also showed that the EE% is inversely proportional to the initially applied iron content. However, even for the sample with the highest initial iron concentration (3 mg Fe/mL), an EE% above 70% was achieved.…”

Section: Stealth Magnetic Liposome Purification and Encapsulation Effsupporting

confidence: 92%

“…For this purpose, iron oxide nanoparticles can be encapsulated into phospholipid vesicles to develop liposomal contrast agents (ie, magnetic liposomes [MLs]). [7][8][9][10][11] Here, we have focused our attention on ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs), which have a hydrodynamic diameter of less than 50 nm. In contrast to superparamagnetic iron oxide nanoparticles (SPIOs; diameters between 70 and 150 nm), which are used as T2 contrast agents, USPIOs additionally show a T1 contrast when applied in moderate concentrations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ultrasmall superparamagnetic iron oxide (USPIO)-based liposomes as magnetic resonance imaging probes

Frascione¹,

Almer²,

Opriessnig³

et al. 2012

IJN

View full text Add to dashboard Cite

Background: Magnetic liposomes (MLs) are phospholipid vesicles that encapsulate magnetic and/or paramagnetic nanoparticles. They are applied as contrast agents for magnetic resonance imaging (MRI). MLs have an advantage over free magnetic nanocores, in that various functional groups can be attached to the surface of liposomes for ligand-specific targeting. We have synthesized PEG-coated sterically-stabilized magnetic liposomes (sMLs) containing ultrasmall superparamagnetic iron oxides (USPIOs) with the aim of generating stable liposomal carriers equipped with a high payload of USPIOs for enhanced MRI contrast. Methods: Regarding iron oxide nanoparticles, we have applied two different commercially available surface-coated USPIOs; sMLs synthesized and loaded with USPIOs were compared in terms of magnetization and colloidal stability. The average diameter size, morphology, phospholipid membrane fluidity, and the iron content of the sMLs were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), fluorescence polarization, and absorption spectroscopy, respectively. A colorimetric assay using potassium thiocyanate (KSCN) was performed to evaluate the encapsulation efficiency (EE%) to express the amount of iron enclosed into a liposome. Subsequently, MRI measurements were carried out in vitro in agarose gel phantoms to evaluate the signal enhancement on T1-and T2-weighted sequences of sMLs. To monitor the biodistribution and the clearance of the particles over time in vivo, sMLs were injected in wild type mice. Results: DLS revealed a mean particle diameter of sMLs in the range between 100 and 200 nm, as confirmed by TEM. An effective iron oxide loading was achieved just for one type of USPIO, with an EE% between 74% and 92%, depending on the initial Fe concentration (being higher for lower amounts of Fe). MRI measurements demonstrated the applicability of these nanostructures as MRI probes. Conclusion: Our results show that the development of sMLs is strictly dependent on the physicochemical characteristics of the nanocores. Once established, sMLs can be further modified to enable noninvasive targeted molecular imaging.

show abstract

Section: Stealth Magnetic Liposome Purification and Encapsulation Effsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Ultrasmall superparamagnetic iron oxide (USPIO)-based liposomes as magnetic resonance imaging probes

Frascione¹,

Almer²,

Opriessnig³

et al. 2012

IJN

View full text Add to dashboard Cite

show abstract

“…However, the encapsulation efficiency of our prepared nanoparticle-loaded liposomes is more than those reported by Sabaté et al [32] for similar nanoparticle concentration used to prepare magnetic nanoparticle-loaded liposomes.…”

Section: Encapsulation Efficiencycontrasting

confidence: 52%

Fabrication and Characterization of Magnetoplasmonic Liposome Carriers

Hassannejad¹,

Khosroshahi

Firouzi³

2014

NSTOA

View full text Add to dashboard Cite

“…Another kind of MLPs is extruded MLPs, which consist of large unilamellar vesicles (with diameters of the order of a few hundred nanometers) encapsulating several small nanometer-sized water-dispersible iron oxide cores in the aqueous cavity. 96,97 As an alternative to the extrusion method, encapsulation of magnetic particles can also be achieved by sonication, inverse phase evaporation, or a combination of these techniques. [98][99][100] Finally, a third kind of MLPs are formed via the precipitation of iron oxides in the inner space of the vesicles.…”

Section: Paramagnetic/superparamagnetic Liposomes: Versatile Mri Probesmentioning

confidence: 99%

Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents

Estelrich¹,

Sánchez-Martín²,

Busquets³

2015

IJN

Self Cite

282

106

View full text Add to dashboard Cite

Magnetic resonance imaging (MRI) has become one of the most widely used and powerful tools for noninvasive clinical diagnosis owing to its high degree of soft tissue contrast, spatial resolution, and depth of penetration. MRI signal intensity is related to the relaxation times ( T 1 , spin–lattice relaxation and T 2 , spin–spin relaxation) of in vivo water protons. To increase contrast, various inorganic nanoparticles and complexes (the so-called contrast agents) are administered prior to the scanning. Shortening T 1 and T 2 increases the corresponding relaxation rates, 1/ T 1 and 1/ T 2 , producing hyperintense and hypointense signals respectively in shorter times. Moreover, the signal-to-noise ratio can be improved with the acquisition of a large number of measurements. The contrast agents used are generally based on either iron oxide nanoparticles or ferrites, providing negative contrast in T 2 -weighted images; or complexes of lanthanide metals (mostly containing gadolinium ions), providing positive contrast in T 1 -weighted images. Recently, lanthanide complexes have been immobilized in nanostructured materials in order to develop a new class of contrast agents with functions including blood-pool and organ (or tumor) targeting. Meanwhile, to overcome the limitations of individual imaging modalities, multimodal imaging techniques have been developed. An important challenge is to design all-in-one contrast agents that can be detected by multimodal techniques. Magnetoliposomes are efficient multimodal contrast agents. They can simultaneously bear both kinds of contrast and can, furthermore, incorporate targeting ligands and chains of polyethylene glycol to enhance the accumulation of nanoparticles at the site of interest and the bioavailability, respectively. Here, we review the most important characteristics of the nanoparticles or complexes used as MRI contrast agents.

show abstract

Preparation and characterization of extruded magnetoliposomes

Cited by 81 publications

References 22 publications

Ultrasmall superparamagnetic iron oxide (USPIO)-based liposomes as magnetic resonance imaging probes

Ultrasmall superparamagnetic iron oxide (USPIO)-based liposomes as magnetic resonance imaging probes

Fabrication and Characterization of Magnetoplasmonic Liposome Carriers

Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents

Contact Info

Product

Resources

About