A Research Of Porphyrin Photosensitizer Fluorescence Detection

The photonics is an emerging subject with comparable electronics, and it isbecoming another material basis and technological means that lead the progress ofhuman society after the electronics. Fluorescence diagnostic techniques have theability to eliminate the influence of the excitation light source instability andchanges of measuring distance and angles. The techniques also have the advantageof no damage，high-precision, high speed, simultaneous detection of a variety ofdiseases which give it a good prospect of application. In this thesis, taking theporphyrin as the object of research we carry out the study of porphyrinphotosensitizer fluorescence imaging technology.A fluorescence spectra measurement system was designed. The system took the405nm LD as excitation source that could provide enough excitation power, and itspread light with optic fibers which make it capable to take single point of thefluorescence excitation and measurement. A known concentration of hematoporphyrinwas measured for many times, and the results indicated that the detection limitation ofthe system was0.08μg/ml, the maximum linear detection concentration30μg/ml andthe detection sensitivity2.33ml/μg. The concentration distribution of the mouse neckplaque was detected by the system, and it showed that the drug concentrationdistribution over time was consistent with drug metabolism.A dual-color fluorescence ratio measurement system was developed. Thesystem simplified the single-point measuring instruments, and reduced the costwhile maintaining high sensitivity. It used the concentration algorithmR=（S₃-0.20S₁）/S₁to eliminate the fuctuation of detection conditions. Theinstrument took the place of spectrometer with a green filter and a red filter,calculated the photosensitizer concentration with the two fluorescence intensityratio. A known concentration of HP was measured by this method, and the resultsshowed that the detection limit of the system was less than0.1μg/ml, the maximumlinear detection concentration could reach30μg/ml and the detection sensitivitywas0.92ml/μg。The distribution of dental calculus was measured by the two pointmeasurement systems and got similar results.A two-dimensional fluorescence imaging system was established, which couldprovide visible photosensitizer distribution of whole detection feld. With referenceto the dual-color fluorescence ratio method, it used the center wavelength of633nmfluorescence image and the533nm center fluorescence image to conduct the ratio of computation, obtained the pseudo color image from the grayscale picture， so thatthe system could effectively overcome the outside interference and improve imageclarity and resolutions. A known concentration of HP was measured by the system,and the results indicated that the detection limit of the system was less than0.1μg/ml, the maximum linear detection concentration could reach40μg/ml. Thedental calculus, mouse neck plaque and kidney images were obtained from theapparatus. As showed of the artificial color images, the photosensitizerconcentration distribution was visible, and it is convenient to observe thedistribution because of the large color gradient.