RESUMO
Bombesin (BBN) was covalently bound to graftable subphthalocyanine (SubPc) or to a cholesterol derivative, a component of a liposome that encapsulates non-graftable SubPc. The latter bioconjugation approach was suitable to address the stability of SubPc and was achieved by copper-free click-chemistry on the outer-face of the liposome. Liposomes were purified (FPLC) and then analyzed in size (outer diameter about 60 nm measured by DLS). In vitro binding studies allowed to determine the IC50 13.9 nM for one component of the liposome, cholesterol, conjugated to BBN. Hence, azido- (or alkynyl-) liposomes give fluorophores with no reactive functional group available on their backbone a second chance to be (indirectly) bioconjugated (with bombesin).
Assuntos
Bombesina/química , Indóis/química , Lipossomos/química , Nanoestruturas/química , Alcinos/química , Azidas/química , IsoindóisRESUMO
A general catalyzed direct C-H functionalization of s-tetrazines is reported. Under mild reaction conditions, N-directed ortho-C-H activation of tetrazines allows the introduction of various functional groups, thus forming carbon-heteroatom bonds: C-X (X=I, Br, Cl) and C-O. Based on this methodology, we developed electrophilic mono- and poly-ortho-fluorination of tetrazines. Microwave irradiation was optimized to afford fluorinated s-aryltetrazines, with satisfactory selectivity, within only ten minutes. This work provides an efficient and practical entry for further accessing highly substituted tetrazine derivatives (iodo, bromo, chloro, fluoro, and acetate precursors). It gives access to ortho-functionalized aryltetrazines which are difficult to obtain by classical Pinner-like syntheses.
RESUMO
Water-soluble disulfonato-subphthalocyanines (SubPcs) or hydrophobic nano-encapsulated SubPcs are efficient probes for the fluorescence imaging of cells. 20 nm large liposomes (TEM and DLS) incorporated about 13% SubPc. Moreover, some of these fluorophores were found to be pH activatable.
