Study On The Toxicity Of CdSe/ZnS Quantum Dots To The Human Skin Cells

Nanostructured semiconductor materials with unique optical properties have generated great research interest in the past decades.It addresses the physical, chemical, materials, biology and other subjects, which has become an emerging cross-disciplinary. The current study is on the materials of Cds, CdSe, CdTe, ZnS, etc. Quantum Dots (QDs) substantively is a kind of semiconductor, which it has unique optical properties including broad-range excitation, size-tunable narrow emission spectra. The size and compostion of QDs can be varied to obtain the desired emission properties. Recent years, it is being used as a new fluorescent probe in biological and medical due to its unique optical properties. Consequently, the professional and public exposure to QDs is supposed to increase dramatically in the coming years. Therefore, QDs are attracting considerable and increasing concern of the public and government worldwide.In the very beginning, we groped and consummated the condition for transfer of culture, cryopreservation and resuscitation of human melanoma cell line (A375,A375.s2) and normal human epidermal cell line (HaCaT). Then we drew out of the proliferation curves of three kinds of cell lines by Cell Counting Kit-8 and observed the appearance of the cells in exponential phase of growth. Followed by, First, we selected human melanoma cell lines (A375,A375.s2) as cell model, and normal human epidermal cells HaCaT cell line as control cell model. Cytotoxicity of CdSe / ZnS QDs-605 and CdSe / ZnS QDs-545 was measured by Cell Counting Kit-8; Second, A375, A375.s2, and HaCaT cell lines were treated with two different sizes QDs-605 and QDs-545 with different sizes, respectively. The cells morphology and cells non-specific binding affected by quantum dots were measured by fluorescence microscopy. Third, According to the figures of fluorescence microscopy and the results of CCK-8 method, respectively, low doses QDs-605 and QDs-545 were screened. The non-specific binding between three cell lines (A375, A375.s2, HaCaT) and two quantum dots (QDs-605, QDs-545) by flow cytometry. Last, PI staining using flow cytometry in a single low dose of quantum dots QDs-545 led to A375, A375.s2, HaCaT cell apoptosis; In this paper, preliminary study of different sizes CdSe / ZnS quantum dots (QDs-605 and QDs-545) cell toxicity and toxicity-related mechanism for CdSe / ZnS quantum dots provided a secure experimental basis. The results of this study were shown as follow:1.Using CCK-8 to detected the toxicity of A375,A375.s2,HaCaT cell lines treated with CdSe/ZnS QDs-545 and CdSe/ZnS QDs-605With the increase of QDs-605 concentration, A375 and A375.s2 cells survival rate decreased. A series of different concentrations of QDs-605 being applied to A375, and A375.s2 cells for 24h, the cell survival rate was lower than control group and there were significant differences between sample group and control group. However, a series of different concentrations of QDs-605 acting on HaCaT cells for 24h, there were significant differences between sample group and control group only at the QDs-605 concentrations of 162, 81, 2.025 and 1.0125nmol/L. A series of different concentrations of QDs-545 being applied to A375 and A375.s2 cells for 24h, the survival rate of sample group was lower than that of control group. There were significant differences between sample group and control group. A series of different concentrations of QDs-605 acting on HaCaT cells for 24h, there were significant differences between sample group and control group only at the QDs-605 concentrations of 162, 54 nmol /L.2. Using fluorescence microscopy to observe changes of cells morphology in A375, A375.s2 and HaCaT cells lines treated with CdSe/Zns QDs-545 and CdSe/Zns QDs-605The A375, A375.s2, HaCaT cell lines were treated different concentrations of the CdSe/ZnS QDs-545 and CdSe/ZnS QDs-605. After 24h incubation, the cell morphology of A375 and A375.s2 changed along with the increase of the concentration. A large area of apoptosis came out in cells on the concentration of 81 -162nmoL. There was not change on the concentration of 540-171nmol/ L in the normal human epidermal cell lines (HaCaT). 3. Using PI staining to detect A375, A375.s2 and HaCaT cell apoptosis treated with CdSe / Zns QDs-545 and CdSe / Zns QDs-605Because of the high sensitivity of flow cytometry, low concentration of QDs-545 were selected to study the toxicity of three cell lines. The results showed that there was apparent peak migration of apoptosis by PI single staining method, indicating the low dose of QDs-545 can cause significant apoptosis in human melanoma cells. However, the apoptosis peak of the migration did not appear in normal human epidermal cell line (HaCaT).4. Non-specific binding of between CdSe/ZnS QDs-545, CdSe/ZnS QDs-605 and A375, A375.s2, HaCaT cell linesIt was concluded that a single low dose can cause human melanoma cells (A375, A375.s2) cell apoptosis by PI staining. Therefore, the non-specific binding of three cell lines was detected by flow cytometry. It was showed that non-specific binding is mainly through phagocytosis. Compared with normal epidermal cells, tumor cells swallowed foreign substances faster.5. Attenuation of QD-induced toxicity in human melanoma cells (A375, A375.s2) by SilibininThe results showed that QD-induced cytotoxicity is prevented with human melanoma cell (A375, A375.s2) pretreatment 2h with the silymarin of concentration 20mg/mL and 10mg/mL significantly (p<0.05), in compare with cell in compare to cell in the presence of CdSe/ZnS QDs-605with untreated Silibinin by MTT assay.