Application of Laser Trapping to Study the Chemo Treated 4t1 Breast Cancer Cells and the Elasticity of Human Red Blood Cells in Sickle Cell Anemia and Sickle Cell Trait.

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Addis Ababa University


The study presents a new method that uses laser trapping (LT) technique for measurement of radiation sensitivity of untreated and chemo-treated cancer cells. A human mammary tumor cell line (4T1) treated by herbal extract from traditional Chinese medicines (TCMs) were studied. We used an anti-tumor compound, 2-Dodecyl-6-methoxycyclohexa-2, 5-diene-1,4-dione (DMDD), which was extracted from the root of AverrhoacarambolaL. A control group of 4T1 breast cancer cells and a two hour and a twenty four hour treated (by DMDD compound) groups of 4T1 cells were used in this study. A high power infrared laser at 1064nm is used to trap single and multiple 4T1 cells from the control and treated groups. The absorbed threshold ionization energy (TIE) and threshold radiation dose (TID) were determined and analyzed using descriptive and t-statistics. The relation of the TIE and TRD to the mass of the individual cells were also analyzed for different hours of treatment in comparison with the control group. The results showed both TIE (81.28mJ, 48.82mJ, and 23.76mJ) and TRD (32.62J/μg, 22.42Jμg, and 9.35μg) decrease with increasing treatment period. On the other hand, as the mass increases the TIE increases but the TRD decreases regardless of treatment by DMDD. Analyses of the TIE and TRD for single vs multiple cells ionizations within each group has also consistently showed this same behavior for both TIE and TRD regardless of the treatment. The underlying factors for these observed relations are explained in terms radio and hypothermia effects resulting from the laser trap and chemo effects resulting from the treatment by the DMDD. The charges developed on untreated, 2-h and 24-h treated cancer cell were 3.28x10-17c, 4.31x10-17c, and 4.93x10-17c. The period of ionization, charge, and charge per unit mass increase as the time of DMDD treatment increase. When the cell ejected from the trap the charge decreases as it is away from the trap. The elastic property of sickle and sickle cell trait cell were analyzed for 49 red blood cell (RBC) samples from each HbAS and HbSS groups. Laser trapping technique with computer controlled piezo-driven stage (PS) was used to trap and stretch both HbAS and HbSS red blood cells. Laser trapping force was formulated in a cylindrical model. Using this trapping force relative percent difference, stiffness and the ratio of maximum (longitudinal) and minimum (transverse) radius was taken to study the elasticity. The result shows that HbAS have higher elastic property than the HbSS red blood cell samples.



Application of Laser Trapping, Study the Chemo Treated 4t1, Breast Cancer Cells, Elasticity of Human Red Blood Cells, Sickle Cell Anemia