Yao Xu, Li Guo-Rui, Wang Jiu-Jiang, Tang Cheng, Li Da-Wu, You Nan, Mao Wei, Li Zhan-Chao, Zhang Si-Qi
College of Petrochemical Engineering, Liaoning Petrochemical University, Fushun, 113001, China.
College of Forensic Science, Criminal Investigation Police University of China, Shenyang, Liaoning, 110035, China.
Anal Methods. 2024 Aug 29;16(34):5864-5871. doi: 10.1039/d4ay00923a.
Powder-dusting method based on the visual contrast between the background surface and powder-covered ridges of a fingerprint is widely used to develop the invisible latent fingerprints (LFPs) left at crime scenes. Recently, the development of nano-sized powders with excellent optical performances has been extensively explored. In this work, we employed environmentally friendly and low-toxicity cellulose nanocrystals as the novel support. Using dye-doped cellulose nanocrystals as novel dusting powders, two dyes (phenylfluorone and curcumin) were adsorbed on the cellulose nanocrystals by a simple batch adsorption method. The dye-doped cellulose nanocrystals (namely, phenylfluorone-doped cellulose nanocrystals (PDCN) and curcumin-doped cellulose nanocrystals (CDCN)) containing 2% of the loaded mass of both the dyes with bright green fluorescence were developed to visualize LFPs on the surfaces of various substrates (such as glass slide, printing paper, orange plastic card, tile, stainless steel, compact disc, red plastic packing, copper foil and aluminum foil). Images of the LFPs can been obtained by both the dye-doped cellulose nanocrystals with sufficient affinity to the ridges of LFPs. High-quality ridge details with features at the second and third level can be detected by CDCN, whereas PDCN only display the secondary-level features of ridge details. Compared with PDCN, CDCN illustrate higher sensitivity, higher selectivity, and better contrast, especially for detecting fresh and non-fresh LFPs on porous and non-porous substrates, and has the potential for practical use in forensic science.
基于背景表面与指纹粉末覆盖纹路之间视觉对比度的粉末喷洒法被广泛用于显现犯罪现场留下的不可见潜在指纹（LFPs）。近年来，人们广泛探索了具有优异光学性能的纳米级粉末的开发。在这项工作中，我们采用了环境友好且低毒性的纤维素纳米晶体作为新型载体。通过简单的批量吸附法，将两种染料（苯基荧光酮和姜黄素）吸附在纤维素纳米晶体上，制备了染料掺杂的纤维素纳米晶体作为新型喷洒粉末。含有2%负载质量的两种染料且具有亮绿色荧光的染料掺杂纤维素纳米晶体（即苯基荧光酮掺杂纤维素纳米晶体（PDCN）和姜黄素掺杂纤维素纳米晶体（CDCN））被用于显现各种基材（如载玻片、打印纸、橙色塑料卡、瓷砖、不锈钢、光盘、红色塑料包装、铜箔和铝箔）表面的潜在指纹。通过对潜在指纹纹路具有足够亲和力的染料掺杂纤维素纳米晶体都可以获得潜在指纹的图像。CDCN可以检测到具有二级和三级特征的高质量纹路细节，而PDCN仅显示纹路细节的二级特征。与PDCN相比，CDCN具有更高的灵敏度、更高的选择性和更好的对比度，特别是对于检测多孔和无孔基材上的新鲜和非新鲜潜在指纹，并且在法医学中具有实际应用潜力。
