Development of latent fingerprints with macromolecular nanomaterials

Finger and palm marks are described as the "Gold Standard of Forensic Sciences" because they are not only one of the most common evidence in crime scene investigations but also low cost and ensure accurate results. Being biometric evidence is also one of the most critical advantages of palm and fingerprint. With the improvement of Automatic Palm and Fingerprint Identification Systems (APFIS) and databases, finger and palm prints gained crucial importance. In order to identify the perpetrator, a sample taken from a crime scene needs to be compared with a sample to taken from a suspect. But with the help of finger and palm print databases, fingerprint evidence can be used to make an identification without a suspect or a comparison sample. Success in finger and palm print examinations lies in detecting the invisible finger and palm marks in the crime scene and successfully developing these latent marks. Although there are many studies on the development of latent finger and palm marks, it is an area that needs more studies. This master thesis; it is aimed to develop an eco-friendly solution that does not harm the health of the user by making use of nanotechnology and nanomaterials, which are considered to be a technological revolution that will dominate after 2025. In the study, A suspension was prepared using silica (SiO2) and graphene in 2-hydroxy ethyl cellulose (2-HEC), a natural, eco-friendly, cellulose derivative macromolecule that is not harmful to health. Characterization of material was carried out by Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction Spectroscopy (XRD), and Scanning Electron Microscope-Energy Dispersive X-Ray Spectroscopy (SEM-EDX) instrumental analysis methods. At the last stage of the study, developed solutions were applied to the 1, 3, 5, 7, and 14-day-old finger marks left on the prepared glass, plastic, aluminum foil, processed wood, untreated wood, paper, and metal surfaces. Overall results show that solutions were prepared successfully in the XRD, FT-IR, and SEM-EDX analysis results. It has been observed that the nanocomposite films formed successfully on selected surfaces other than paper and untreated wood surfaces. Nanocomposite films successfully lift the latent finger marks and have a flexible and protective structure for the latent finger marks. Remove traces, and have a flexible structure that protects traces. It has been observed that the latent marks lifted with nanocomposite films are suitable for further finger mark development methods. It is evaluated that nanocomposite films can simultaneously protect and develop marks. Overall, test results show that solutions with AKN are more successful than others, and the most successful solution was 2-HEC/neutral SiO2/AKN. In order to test the applicability of the solutions with alternative methods, the solutions were tested by steaming, dipping, and spraying methods. As a result of applying the solutions with these methods, the expected outcomes have not been achieved. It is considered that successful results can be obtained with the necessary improvements and determination of appropriate values for the steaming and spraying method. Overall, by using the results of this study, a contribution to the Forensic Sciences literature has been made by developing a low-cost, harmless-to-user health and effective solution on different surfaces using eco-friendly cellulose-derived macromolecule materials.