Portions of electrospun fibermats were collected and weighted (typically around 10 mg). The fibers were soaked with a methanol/water mixture (40:60vol%) for 5 min and then washed two times with water. Then, fibers suspended in water were sonicated (Branson 150 sonicator probe 4C15) for 2x6min at 60% power in continuous mode in an ice bath to avoid over heating of the samples. The resulting nanorods suspensions were washed 4 times with sterile DPBS under sterile conditions to remove traces of fluorescent dyes that leaked during sonication. The sonication seems powerful enough to kill most of microorganisms. If handled in sterile conditions after sonication, no contaminations of cellular samples have been observed during this study. For pluronic F127 treatment, nanorods were centrifuged and resuspended in a pluronic solution in water below CMC value (0.5 mg/mL). After 1 h at 25 °C, 300 rpm in a thermoshaker excess of pluronic was removed by short centrifugation to resuspend nanorods in DPBS. Absolute quantum yields of the electrospun nanofibers were determined using an integration sphere (SC-30 Module, Edinburg Instruments). Transmission electron microscopy has been performed by the electron microscopy platform of IGBMC on a Tecnai F20 (200 kV FEG) system with negative staining from uranyl acetate.