Study on the Development of Latent Blood Fingerprints by New Fluorescein Reagents Based on Fluorescence Labeling Technology

In order to improve the development effect of latent blood fingerprint, this paper attempts to introduce fuorescent labeling technology into latent blood fngerprint development. By taking advantage of the characteristics of strong esterification activity of N-hydroxy-succinimide ester, easy reaction with the amino group of protein to form amide chemical bond and stable structure, a new fluorescence derivative 5-carboxyfluorescein-N-hydroxy-succinimide ester (CFSE) was synthesized and applied to latent blood fngerprint development area for the frst time. In this paper, the developing ability of CFSE on latent blood fingerprint will be systematically explored. By setting a series of gradients, using comparative experiments, hypothesis testing and other methods, the operation method and optimal reagent formula of the fuorescein to develop latent blood fngerprints were determined. CFSE can be widely used in the development of latent blood fngerprints on non-permeable complex backgrounds and dark background objects, and has little effect on sample DNA extraction, and compared with acid yellow, the results showed that the fneness of the lines and the contrast with the background were higher. In addition, the study also determined the order of using CFSE in combination with the common methods for developing latent blood fngerprints. CFSE has the advantages of strong fuorescence brightness, high fneness, obvious contrast with the background, less fuorescence stains, and easy washing, and the overall effect is better, which provides a new method for latent blood fngerprints development.