Application of the Z-scan technique for the detection of CFCDNA (cell-free circulating DNA) and urine DNA (uDNA) in patients with bladder cancer

摘要

Background: Patients with BC have a higher amount of cell-free circulating DNA (CFCDNA) in the blood and urine than healthy people. We aimed to verify if the Z-Scan method could analyze the concentrations of uDNA (urinary) and pDNA (plasma) in relation to the time of collection during treatment for patients with bladder cancer.Methods: Peripheral blood and urine samples were obtained from 30 patients with BC at the time of diagnosis, 45, 90 and 180 days after initiating treatment; 5 mu L of k-DNA (k = u or p) was added in 250 mu L a solution of 1:1000 Ethidium Bromide dye (EtBr) in water. Continum laser Nd:YVO4, wavelength lambda = 532 nm was used. Samples of uDNA and pDNA in water were submitted to the laser with an incident power of 84.5 mW and an exposure time of 30 ms.Results: There was a different concentration of pDNA and uDNA during the treatment of patients using both optical techniques. However, the reaction rate of pDNA and uDNA was similar with spectrophotometry, whereas the z-scan technique presented different values.Conclusion: Z-scan technique has potential for use in the differentiation of pDNA and uDNA concentrations, which are distinct in patients with BC and healthy people.