Unsymmetric vesicles with a different design on each side for near-infrared fluorescence imaging of tumor tissues. Issue 19 (2nd February 2015)

• Record Type: Journal Article
• Authors: Uesaka, Akihiro; Hara, Isao; Imai, Tomoya; Sugiyama, Junji; Kimura, Shunsaku
• Is Part Of: RSC advances. Volume 5:Issue 19(2015)
• Page Start: 14697
• Page End: 14703
• Publication Date: 2015-02-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c4ra15635h
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A new method for preparation of unsymmetric vesciles about chemical decoration of the outer or inner surface of the membrane makes it improved for tumor imaging. Abstract : Spherical vesicular assemblies with unsymmetric membranes are prepared from A3 B-type and AB′-type peptides with different helix senses in the hydrophobic B and B′ blocks under the control of three associated factors: stereo-complex formation, dipole–dipole interactions, and steric effects. [(Sar)26 ]3 - b -(l -Leu-Aib)6 (A3 BL ), (Sar)27 - b -(l -Leu-Aib)6 (ABL ), (Sar)28 - b -(d -Leu-Aib)6 (ABD ), lipoic-acid terminatedABL (lipoABL ), and lipoic-acid terminatedABD (lipoABD ) are mixed while keeping equimolar ratios of the total amounts of the right- and the left-handed helices. WhenA3 BL exceeds more than 60% of all the right-handed helices of the mixture, the unsymmetric vesicles are formed, as indicated by the selective adsorption of gold nanoparticles on the vesicle surface observed by TEM. The unsymmetric vesicles are also prepared usingICGABL andICGABD with a near-infrared fluorophore, indocyanine green (ICG), at the terminals ofABL andABD . The unsymmetric vesicle formation is verified by fluorescence quenching with the addition of In ions to the solution. When these vesicles are injected into tumor-bearing mice, the vesicles are effectively accumulated into tumor tissues via the EPR effect. The unsymmetric vesicle containing ICG at the inward surface induces less IgM production than that with ICG at the outward surface. More stealth vesicles in the blood stream are therefore obtainable by concealing the imaging fluorophores in the vesicle.