In vitro gastric cancer cell imaging using near-infrared quantum dot-conjugated CC49.

In this experiment, we developed a bioprobe label for immunofluorescence using gastric tumor-specific quantum dots (QDs) to detect gastric tumor cells in vitro. The fluorescent probe, which is capable of specifically labeling gastric tumor cells, was constructed by taking advantage of the unique and superior properties of QDs. We grafted primary QDs onto the tumor-associated glycoprotein 72 (TAG-72) monoclonal antibody CC49 to produce CC49-QDs that specifically label tumor cells. Following a series of tests on the diameter and emission spectrum of CC49-QDs, they were employed in immunofluorescence analysis. Transmission electron microscopy and fluorescence spectrum analyses indicated that CC49-QDs had a 0.25 nm higher average diameter than the primary QDs, and that the grafted CC49 had no difference in optical properties compared to the primary QDs. In cell imaging, the cells labeled with CC49-QDs generated brighter fluorescence compared with the cells of the primary QD group. The results of immunofluorescence analysis demonstrated that antibody grafting reinforced the specific binding of QDs to tumor cells. This probe may also be further applied to live gastric cancer animal models to track lymphatic metastasis. In addition, it may potentially offer theoretical support for lymphadenectomy in the treatment of gastric cancer.