Browsing by Subject "LOADED LIPOSOMES"

Sort by: Order: Results:

Now showing items 1-2 of 2
  • Shakirova, Julia R.; Sadeghi, Amir; Koblova, Alla A.; Chelushkin, Pavel S.; Toropainen, Elisa; Tavakoli, Shirin; Kontturi, Leena-Stiina; Lajunen, Tatu; Tunik, Sergey P.; Urtti, Arto (2020)
    Two iridium [Ir(NC)(2)(NN)](+) complexes with the diimine NN ligand containing a long polymethylene hydrophobic chain were synthesized and characterized by using NMR and ESI mass-spectrometry: NN - 2-(1-hexadecyl-1H-imidazol-2-yl)pyridine, NC - methyl-2-phenylquinoline-4-carboxylate (Ir1) and 2-phenylquinoline-4-carboxylic acid (Ir2). These complexes were used to prepare the luminescent PEGylated DPPC liposomes (DPPC/DSPE-PEG2000/Ir-complex = 95/4.5/1 mol%) using a thin film hydration method. The narrowly dispersed liposomes had diameters of about 110 nm. The photophysics of the complexes and labeled liposomes were carefully studied. Ir1 and Ir2 give red emission (lambda(em) = 667 and 605 nm) with a lifetime in the microsecond domain and quantum yields of 4.8% and 10.0% in degassed solution. Incorporation of the complexes into the liposome lipid bilayer results in shielding of the emitters from interaction with molecular oxygen and partial suppression of excited state nonradiative relaxation due to the effect of the relatively rigid bilayer matrix. Delivery of labeled liposomes to the cultured ARPE-19 cells demonstrated the usefulness of Ir1 and Ir2 in cellular imaging. Labeled liposomes were then injected intravitreally into rat eyes and imaged successfully with optical coherence tomography and funduscopy. In conclusion, iridium complexes enabled the successful labeling and imaging of liposomes in cells and animals.
  • Mastrotto, Francesca; Brazzale, Chiara; Bellato, Federica; De Martin, Sara; Grange, Guillaume; Mahmoudzadeh, Mohamad; Magarkar, Aniket; Bunker, Alex; Salmaso, Stefano; Caliceti, Paolo (2020)
    The colloidal stability, in vitro toxicity, cell association, and in vivo pharmacokinetic behavior of liposomes decorated with monomethoxy-poly(ethylene glycol)-lipids (mPEG-lipids) with different chemical features were comparatively investigated. Structural differences of the mPEG-lipids used in the study included: (a) surface-anchoring moiety [1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE), cholesterol (Chol), and cholane (Chin)]; (b) mPEG molecular weight (2 kDa mPEG and 5 kDa mPEG(114)); and (c) mPEG shape (linear and branched PEG). In vitro results demonstrated that branched (mPEG(114))(2)-DSPE confers the highest stealth properties to liposomes (similar to 31-fold lower cell association than naked liposomes) with respect to all PEGylating agents tested. However, the pharmacokinetic studies showed that the use of cholesterol as anchoring group yields PEGylated liposomes with longer permeance in the circulation and higher systemic bioavailability among the tested formulations. Liposomes decorated with mPEG(114)-Chol had 3.2- and similar to 2.1-fold higher area under curve (AUC) than naked liposomes and branched (mPEG(114))(2)-DSPE-coated liposomes, respectively, which reflects the high stability of this coating agent. By comparing the PEGylating agents with same size, namely, linear 5 kDa PEG derivatives, linear mPEG(114)-DSPE yielded coated liposomes with the best in vitro stealth performance. Nevertheless, the in vivo AUC of liposomes decorated with linear mPEG(114)-DSPE was lower than that obtained with liposomes decorated with linear mPEG(114)-Chol. Computational molecular dynamics modeling provided additional insights that complement the experimental results.