Structural and photophysical evaluation of O-alkoxy substituted BODIPY dyes in liposomes

Bright and easy to synthesize probes for bioimaging read-outs are constantly required to visualize and deeply understand biochemical structures and functionalities. Hence, the visualization of cellular membranes is key due to their biological role. In this work, six rationally designed alkoxy-substituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) fluorophores have been synthesized and investigated. This design aims to evaluate how the presence of structurally different short ethylene glycol subunits in para-position of meso-phenyl substituted BODIPY impacts on the overall molecular hydrophilic/hydrophobic balance, on the related optical properties and on the staining of lipid bilayer membranes in large unilamellar vesicles (LUVs) as cell membrane models. The photophysical properties have been deeply studied with respect to the probe structure obtaining versatile key data to support the design of new fluorescent sensors for biological applications.