ESPCI web site
Monday January 15 at 2:00 pm (Paris time)
Room Charpak, Entrance building, ground floor
Polarized Nano-Emitters as Orientation Probes in Biofluids
Retrieving orientational information plays an important role in many fields, e.g. microfluidics and biology. Measuring polarized luminescence provides a powerful tool to decrypt the orientation. Optical probes can be quantum dots and organic molecules as well as lanthanide-doped nanocrystals. Recently, our group has developed a technique based on Eu3+-doped anisotropic nanorod systems to probe the orientation of a single nanorod and the collective nanorods partially aligned by flow-induced shear force. Further, we succeeded in producing colloidal nanorods with high quantum efficiency and strong polarization properties. Facile and efficient surface functionalization was then developed with specifically designed zwitterionic polymers collaborated with ESPCI. The colloidal suspension of the nanorods in physiological media showed outstanding biocompatibility, colloidal stability, and even a liquid crystalline behavior. By flowing the suspension ina microfluidic channel and collecting the polarized emission locally in a confocal microscope, a relation between shear stress and order parameter was established. In this regard, shear stress tomography could be realized in complex microfluidic channels with constrictions and cultured cells. All the study enables the use of the nanorods as orientation/imaging probes in biosystems and provides the whole package of shear stress determination in biofluids.
