Two-photon-excited tumor cell fluorescence targeted imaging based on transferrin-functionalized silicon nanoparticles

Transferrin-functionalized silicon nanoparticles (Trf-SiNPs) with two-photon-excited fluorescence were fabricated and utilized for targeted fluorescence imaging in tumor cells. • A facile and feasible fluorescence probe of transferrin-functionalized SiNPs were fabricated. • Trf-SiNPs featured the excellent optical properties, especially the up-conversion fluorescence. • Trf-SiNPs exhibited the good targeted fluorescence imaging capability in tumor cells. • Trf-SiNPs demonstrated the satisfactory two-photon imaging ability in tumor cells. Transferrin-functionalized silicon nanoparticles (Trf-SiNPs) were fabricated and utilized for targeted fluorescence imaging in tumor cells. Silicon nanoparticles (SiNPs) was firstly synthesized by microwave irradiation method, and then coupled with transferrin in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). The structural informations of Trf-SiNPs were measured by transmission electron microscope and Fourier transform infrared spectrometer. The optical properties of Trf-SiNPs were characterized by ultraviolet absorption spectrum, fluorescence emission spectrum, fluorescence quantum yield, fluorescence lifetime, photo-stability, and so on. MTT assay evidenced the low toxicity of Trf-SiNPs. Finally, Trf-SiNPs were successfully applied in HeLa cells and HepG2 cells for targeted fluorescence imaging under single-photon excitation and two-photon excitation.