In this paper, we present a new facile and environmental friendly method to prepare water-soluble
near-infrared (NIR)-emitting PbS quantum dots (QDs) at room temperature under ambient conditions, using
dihydrolipoic acid (DHLA) as a stabilizer. The photoluminescence (PL) emissions of the prepared DHLA-capped
PbS QDs are tunable between 870 and 1010 nm. A PL quantum yield (QY) of ~10% can be achieved under
optimized conditions without any post-preparative treatment. Here, we further use the produced DHLA-capped PbS
QDs for NIR fluorescence imaging in a mouse model. The obtained experimental results showed that the NIR
fluorescence of the PbS QDs in living tissues generated from the excitation with semiconductor laser (λmax=765.9
nm) could penetrate living tissues and be detected easily by the noninvasive in vivo NIR fluorescence imaging
system. In addition, the preliminary studies on the cytotoxicity and in vivo toxicity of the QDs also indicates fully
that these water-soluble DHLA-capped PbS QDs are very lowly toxic, and as such they should have greater
potential in biological and medical applications especially in noninvasive in vivo fluorescence imaging of mice,
compared to other existing highly toxic aqueous NIR-emitting quantum dots (CdTe, HgTe, etc).
Nanoparticles have a promising application prospect in biomedical field. The study of their dynamic characteristics
including in vivo distribution and clearance has the most important significance on their biological application. In this
paper, bio-distribution and clearance of solid and colloid nanoparticles with different size in mouse model was
intensively studied in vivo by using near infrared optical imaging technique. Here, nanohydrogels were synthesized by
precipitation polymerization method and the size of the nanohydrogel could be arbitrarily manipulated according to
different surfactant concentration. Near infrared fluorescence dye were entrapped into their inner core for in vivo studies.
Meanwhile, the size of CdHgTe/SiO2 solid nanoparticles could be controlled by the thickness of SiO2 coated on the
surface of CdHgTe. The results from the near infrared imaging showed that nanohydrogels with different size have the
similar tissue distribution but CdHgTe/SiO2 nanoparticles in different size have a size-dependent organ specification.
These results provided an important reference for the design of targeted drug delivery systems and their biomedical