Near Infrared Quantum Dots Based Non Invasive In Vivo Imaging Of Oral Squamous Cell Crcinoma BCACD885 And Squamous Cell Crcinoma U14

Objective :To explore the competence of near-infrared luminescent quantum dots for visual in vivo imaging on oral squamous carcinoma BcaCD885 cells and squamous carcinoma U14 cells.Methods: Peptide-conjugated near-infrared quantum dots, with an emission wavelength of 800 nm (QD800), were used to label BcaCD885 cells and U14 cells by endocytosis. The QD800-labeled BcaCD885 cells were inoculated in the dorsum subcutaneous, back muscle and under the cheek oral mucosa of nude mice at cell counts of 1×10~3, 1×10~4, 1×10~5, and 1×10~6 respectively. The QD800-labeled U14 cells were inoculated in the dorsum subcutaneous, back muscle of Kunming mice with or without fur at cell counts of 1×10~3, 1×10~4, 1×10~5, and 1×10~6 respectively. At different time points, these mice were examined by an in vivo imaging system to investigate the sensitivity of QD800 to visual detection and the conditions of dynamic imaging in BcaCD885 cells and U14 cells.Results: For nude mice, the minimum detectable counts of BcaCD885 cells for QD800-based in vivo imaging were 1×10~4 in the dorsum subcutaneous, back muscle and under the cheek oral mucosa. For fur-removed Kunming mice, the minimum detectable counts of U14 cells for QD800-based in vivo imaging were 1×10~4 in the dorsum subcutaneous, back muscle; for preserved Kunming mice, the minimum detectable counts of QD800 labeled U14 cells in vivo imaging were 1×10~5 in the dorsum subcutaneous. As tissue depth increased, the detectable fluorescence intensity dropped; as cell counts increased, the fluorescence intensity and the visual image duration also increased, especially for the QD800-labeled BcaCD885 cells in which counts of 1×10~6 were visual imaged in the dorsum subcutaneous, back muscle and under the cheek oral mucosa for 16 d. For fur-removed Kunming mice, QD800-labeled U14 cells with counts of 1×10~6 were visual imaged in the dorsum subcutaneous and back muscle for 16 d. Compared with fur-removed Kunming mice, the detection sensitivity of QD800 for U14 cells reduced by 10 folds in fur-preserved Kunming mice, and imaging time contracted by 80%.Conclusion:Our study successfully used cell-penetrating peptides to conjugate near-infrared quantum dots for the first time and labeled oral squamous carcinoma cells with quantum dot conjugates by endocytosis for visual in vivo imaging. Because of the strong penetration power to tissues, near-infrared quantum dot technology exhibits great promise for the early diagnosis, visual observation and individualized treatment of cancer. But animal fur has a serious impact on the detection sensitivity and duration of QD-based in vivo imaging, it is necessary to remove fur before in vivo imaging.