Nanofibras fluorescentes à base de policaprolactona e derivados de dansila para revelação de impressões digitais latentes

Abstract

This work describes the process of developing nanofibers endowed with fluorescence from a polymer solution based on polycaprolactone (PCL) with the addition of dansyl derivatives, produced through the electrospinning method and characterized by morphological, structural, thermal and fluorescence analyses. The employed methodology enabled the development of homogeneous mats, composed of sets of uniform nanofibers, in addition to distinct particularities related to the type of incorporated fluorophore (Dansylcadaverine, Dansylglycine and Dansyl Chloride). The best experimental conditions for the formation of smooth nanofibers without structural defects were found with 2% of the fluorophore concentration (Dansylcadaverine and Dansylglycine), a working distance between the metallic capillary and the collector of 120 mm, and na applied voltage of 17 kV. Regarding the luminescent properties, the electrospun mats with the addition of Dansyl Glycine showed a performance that was up to 64% superior with respect to the relative intensity of the fluorescence when compared to the mats produced with the incorporation of Dansyl Cadaverine. Based on the properties identified in the produced samples, it was possible to design new applications for the fluorescent nanofibers produced by the electrospinning process. As such, the obtained results proved to be promising for applications in forensic science, since the developed study provided a convenient strategy for the improvement of visual contrast of latent fingerprints on metal surfaces when exposed to ultraviolet light. This innovative approach allows for the visualization of dactyloscopic images with high definition, ridge pattern recognition, fingerprint class distinction and unique points. The electrospinning of the fluorescent mat on metallic surfaces developed in this study, therefore, emerges as a complementary technique for revealing latent fingerprints due mainly to the quality of the developed image, the processing ease of the electrospinning technique and its relatively low operational cost.