Synthesis and characterization of self-assembled CdHgTe/gelatin nanospheres as stable near infrared fluorescent probes in vivo

This work presented a kind of novel near infrared emitting CdHgTe/gelatin nanospheres which were synthesized with Cd(NO3)2, Hg(NO3)2, NaHTe and a thiol stabilizer in gelatin solution. The self-assembled nanospheres were megranate-like and nearly 40 nm in diameter, with CdHgTe QDs uniformly embedded in gelatin matrix. They exhibited strong fluorescence ranging from 580 to 800 nm that could be tuned by molar ratios of Hg2+ and gelatin. The full widths at half-maximum of the emission spectra were in the range of 60–80 nm. Compared with bare CdHgTe QDs, the photostability of this compact complex nanostructure remarkably improved. Moreover, the fluorescence of CdHgTe/gelatin nanospheres was much more resistant to the interference from certain kinds of endogenous biomolecules such as HSA, transferrin and hemoglobin. Further applications of living cells and mouse imaging were demonstrated with an in vivo near infrared fluorescence imaging system. The inherent advantages of high stability as well as high fluorescence intensity make the nanospheres particular interested NIR bioprobe candidates for in vivo imaging studies.