The interactions between nanoparticles and living cells were investigated by an imaging technique of fluorescence microscopy. For this pur- pose, the C60 derivative C60(C(COOH)2)2, a thera- peutic agent for degeneration diseases of central nervous system, was synthesized, purified and characterized. Its interaction with the living cell and penetration of the cellular membrane were in situ studied using the real time imaging technique, and its potential cytotoxicity was also examined by flow cy- tometry. The results indicate that C60(C(COOH)2)2 can easily enter cells, and is mainly located in cytoplasm by fluorescein labeling. Furthermore, C60(C(COOH)2)2 can carry the molecule that cannot cross cellular membranes into cells, because fluo- rescein compound itself cannot enter the cell or ad- here to membrane. At concentrations ranging from 1×10?2 to 1×102 mg/L, C60(C(COOH)2)2 does not show any detectable cytotoxicity.
Liver, as an important metabolic and detoxi- cological organ of human body, can be used as a good bioin- dicator for evaluating body burden of environmental pollut- ants. Its elemental contents and their chemical forms are closely related to the status of human health and disease. In this paper, the liver samples collected from normal subjects were separated to different subcellular fractions of nuclei, mitochondria, lysosome, microsome and cytosol by differen- tial centrifugation. Then their concentrations of heavy metals of As, Pb, Cd, and Hg were determined by atomic absorption and atomic fluorescent spectroscopy. Our results show no significant difference with literature ones when comparing their gross concentrations. In the case of their subcellular distribution, the Hg concentrations are higher in mitochon- drial, microsomal and cytosolic fractions; the Cd concentra- tions are higher in cytosolic and mitochondrial fractions, while As highest in nuclear fraction. The highest concentra- tion of Pb is found in microsomal fraction with similarity to Fe. Mercury in liver is mainly in the form of inorganic, and methylmercury ranged from 9% to 50% with the average value of 20.9%±13.3%. These results indicate that the cellu- lar distribution and the accumulated target organelles are quite different among these heavy metals, which suggest their various pathways and toxic mechanism in vivo.
