Super blinking and biocompatible nanoprobes based on dye doped BSA nanoparticles for super resolution imaging

As one of the super-resolved optical imaging techniques, single molecule localization microscopy (SMLM) received considerable attention due to its impressive spatial resolution. Compared with other fluorescence imaging techniques, SMLM has one particular request for the fluorophores, that is, continuous 'on' and 'off' behaviors of their signals (referred to as 'blinking'). Hence, we present here a kind of super blinking and biocompatible nanoprobes (denoted as SBNs) for SMLM. The SBNs have two main advantages, first, they possess an outstanding fluorescence blinking. Second, they are biocompatible since they are based on bovine serum albumin (BSA). The SBNs are fabricated by doping organic dyes into BSA nanoparticles. We fabricated two kinds of SBNs, one was doped with Alexa Fluor 647 (A647) and the other was doped with Alexa Fluor 594 (A594). Especially for A594 doped SBNs, the improved blinking of A594 doped SBNs induced a better localization precision as compared with A594 alone. Moreover, SMLM imaging of breast cancer cells and exosomes using the SBNs was successfully realized with high spatial resolutions. The work demonstrated here provides a new strategy to prepare novel kinds of super blinking fluorescent agents for SMLM, which broadens the selection of suitable fluorophores for SMLM. (paper)