Fluorescent polymer markers photoconvertible with a 532 nm laser for individual cell labeling

Fluorescent photoconvertible materials and molecules have been successfully exploited as bioimaging markers and cell trackers. Recently, the novel fluorescent photoconvertible polymer markers have been developed that allow the long-term tracking of individual labeled cells. However, it is still necessary to study the functionality of this type of fluorescent labels for various operating conditions, in particular for commonly used discrete wavelength lasers. In this article, the photoconversion of fluorescent polymer labels with both pulsed and continuous-wave lasers with 532 nm-irradiation wavelength, and under different laser power densities were studied. The photoconversion process was described and its possible mechanism was proposed. The peculiarities of fluorescent polymer capsules performance as an aqueous suspension and as a single capsule were described. We performed the successful nondestructivity marker photoconversion inside RAW 264.7 monocyte/macrophage cells under continuous-wave laser with 532 nm-irradiation wavelength, showing prospects of these fluorescent markers for long-term live cell labeling.