Analyzing Proteins By Capillary Electrophoresis Coupled With Light-Emitting Diode Induced Fluorescence

Traditional diagnosis methods of bladder cancer are cystoscopy and cytology, these methods have limitations. To instead of the traditional examination, Tumor markers become the preferred method. Therefore, tumor marker which has high specificity and sensitivity and can be used to screen bladder tumor, is badly in needed. The method of using proteomics for tumor markers is one of effective methods. Using proteomics compare the urine proteins difference between normal peoples and patients with bladder cancer is one of the effective methods.Capillary electrophoresis-in column optical fiber light-emitting diode induced fluorescence is a high performance separation technique. In column optical fiber light-emitting diode induced fluorescence (IC-OF-LED-IF) uses optical fiber insert capillary to the detection window, which leads excitation source directly illuminate the fluorescent material, improve the photon utilization, reducing the background noise.This article intends to establish CE-LED-IF analysis method for detection of human serum albumin, discusses the value of this method. Then, using the apparatus detects the difference between normal human urine proteins and urine proteins of patients with bladder cancer. Objective1. The method for quantitative detection of HSA by CE-LED-IF is built, and laying the foundation for urine protein by the same way;2. Comparison of protein in urine of patients with bladder cancer and normal people, finding differences between two group samples, explore the value of CE-LED-IF in the detection of bladder cancer. Methods1. In this paper, instrument’s structure was improved. Then, discussed the effect of fluorescein, LED and optical filter, derivatives conditions. Under the optimal conditions, a range of concentrations of standard HSA solution were tested by electrophoresis. Finally, we achieved regression equation and the low of detection limit, repeatability, stability, and sample recovery rate. Using established testing methods, test4samples’HSA concentration which was normal human serum.2. Respectively, we collected5cases urine sample from normal people and bladder cancer patients. Proteins in urine were extracted by salting out process. After fluorescent label, extracted proteins were analyzed by CE-LED-IF and electrophoretogram were achieved. From electrophoretogr-am, the distinction was observed. Results1. Performance of instrument was improved by better design for optical path and electrophoresis board of the instrument. The schematization is effective. Choosing FITC lable proteins,480nm wavelength LED as excitation optical source,470-490nm and510-550nm bandpass optical filter. The detection system displayed linear dynamic range from1.52～758×10-1mol·L-1. The low of detection limit was7.5×10-8mol·L-1. From electrophoretograms, the running time of HSA and FITC respectively was210s and400s. HSA concentration of4sample were normal.2. There were obviously difference in electrophoretograms between normal group and patients with bladder cancer.Conclusions1. Using improved instruments to build CE-LED-IF method for detection of HSA, the repeatability and stability, sample recovery rate were good. Experiments have shown that CE-LED-IF can be used in detection of human serum albumin levels in the blood. The method is low detection limit and can be used for measuring low concentrations of HSA.2. Experimental results show that CE-LED-IF can detect difference between normal and protein in urine of patients with bladder cancer. There is potential value this method in the analysis of urine proteins and exploring bladder cancer markers.