Multilamellar LipoCEST Agents Obtained from Osmotic Shrinkage of Paramagnetically Loaded Giant Unilamellar Vescicles (GUVs)

Abstract

Moving from nano‐ to micro‐systems may not just be a matter of scale, but it might imply changes in the properties of the systems that can open new routes for the development of efficient MRI contrast agents. This is the case reported in the present paper, where giant liposomes (giant unilamellar vesicles, GUVs) loaded with LnIII complexes have been studied as chemical exchange saturation transfer (CEST) MRI contrast agents. The comparison between nanosized liposomes (small unilamellar vesicles, SUVs) and GUVs sharing the same formulation led to differences that could not be accounted for only in terms of the increase in size (from 100–150 nm to 1–2 μm). Upon osmotic shrinkage, GUVs yielded a saturation‐transfer effect three order of magnitude higher than SUVs consistent with the increase in vesicles volume. Confocal microscopy showed that the shrinkage of GUVs resulted in multilamellar particles whereas SUVs are known to yield asymmetrical, discoidal shape.

Supramolecular adducts between macrocyclic Gd(iii) complexes and polyaromatic systems: a route to enhance the relaxivity through the formation of hydrophobic interactions

“…In order to assess the eventual cell toxicity of the supramolecular adduct, MTT assays have been carried out, as previously reported. 38 …”

“…Tests to assess the toxicity of Gd-HPDO3A/pyrene supramolecular adducts were carried out by using TS/a breast cancer cells and applying MTT assay. 38 TS/a cells were seeded into 96-well tissue culture plates (10 4 cells for plate) 24 h before the experiment. Then, they were incubated with fresh complete medium in the presence of (i) Gd-HPDO3A, (ii) Gd-HPDO3A/HPTS, (iii) Gd-HPDO3A/HDPS or (iv) Gd-HPDO3A/PTS.…”

“…In order to assess the eventual cell toxicity of the supramolecular adduct, MTT assays have been carried out, as previously reported. 38 Please do not adjust margins Please do not adjust margins TS/A cells were incubated in the presence of i) Gd-HPDO3A, ii) Gd-HPDO3A/HPTS, iii) Gd-HPDO3A/HDPS or iv) Gd-HPDO3A/PTS in the 1:3 mol/mol stoichiometric ratio, at four different concentrations (Fig.5). The obtained results show a cell viability higher than 95% for all the tested concentrations and for all the investigated adducts, i.e.…”

Detection of U-87 Tumor Cells by RGD-Functionalized/Gd-Containing Giant Unilamellar Vesicles in Magnetization Transfer Contrast Magnetic Resonance Images

“…with targeting moieties is a particular advantage. 23,33 Cyclic RGD has been used, herein, for its binding to integrins. The RGD tripeptide (Arg-Gly-Asp) is an amino acid sequence that is largely present in many extracellular matrix proteins (e.g.…”

“…Giant liposomes were prepared according to a procedure reported in the literature with modifications. 23,33 Membranes were prepared using the following formulations:…”