手印纳米显现效果的评价研究进展

近些年来，将量子点、金属及金属氧化物纳米材料、稀土上转换及下转换发光纳米材料、荧光碳点、金属-有机框架材料、聚集诱导发光材料等新型材料应用于手印显现领域的研究日益增多，由此衍生出一类新兴的手印显现技术--手印纳米显现技术。手印纳米显现技术具有操作简单、方法灵活、效果显著、适用广泛等突出优势，已经成为传统手印显现技术的重要补充。国内外研究人员对手印纳米显现技术的探索主要集中在显现材料的推陈出新和显现方法的交叉融合两方面，而对手印显现效果的影响因素及综合评价等研究却较为分散且缺乏系统性。准确客观地评价手印纳米显现效果对于显现方法的合理选择和物证价值的客观评估都具有非常重要的意义。该综述从对比度、灵敏度、选择性、毒害性等四方面对手印显现特别是手印纳米显现的效果评价方法进行梳理总结，并对影响手印纳米显现效果的诸多因素分别进行讨论。纳米材料的发光性质主要决定了手印显现的对比度，纳米材料的微观形貌和颗粒尺寸主要决定了手印显现的灵敏度，纳米材料的吸附性能和表面性质主要决定了手印显现的选择性，因此可通过调整显现材料的诸多性质来提升改善手印纳米显现的效果。最后，对手印纳米显现未来的发展方向提出全新展望。纳米显现材料必然由单一发光性能向多元发光性能过渡，由现有材料的借鉴使用向形貌尺寸的精细操控过渡，由表面简单处理向靶向分子修饰过渡，由潜在毒害材料向绿色环保材料过渡；纳米显现方法必然由强背景干扰向弱背景干扰发展，由细节特征的清晰显现向汗孔特征的清晰显现发展，由物理吸附向靶向识别发展，由痕迹物证的高效显现向生物物证的微观无损发展。同时建议科研人员在注重提升手印显现效果的同时，更加重视对手印显现效果的定量评价研究，进而促进手印纳米显现技术体系的完善，也可使手印纳米显现技术在刑事科学技术领域中发挥出重要的作用。

Research Progress on Evaluating the Effects of Nanomaterial-Based Development of Latent Fingerprints

Researches on latent fingerprint development using novel nanomaterials including quantum dots, metal and metal oxide nanomaterials, rare-earth doped up- and down-conversion luminescent nanomaterials, carbon dots, metal-organic frameworks, and aggregation-induced emission materials have mushroomed in recent years, resulting in the emergence of nanomaterial-based development of latent fingerprints. Fingerprint development employing nanomaterials has some outstanding advantages such as simple operation, flexible approach, remarkable effect, and wide applicability, which can be served as an important supplement to the traditional techniques. So far, most studies have focused on discovering new nanomaterials and the advancement of new methods for latent fingerprint development. However, research on the influence factors and the comprehensive evaluations for the effects of fingerprint development still remains scattered and unsystematic. The accurate evaluation of fingerprint development effects is of great significance to the reasonable selection of developing methods and the objective assessment of physical evidence. In this review, we systematically summarized the evaluation methodologies on the effects of nanomaterial-based development of latent fingerprints from four aspects, namely, contrast, sensitivity, selectivity, and toxicity. In addition, the influence factors on the effects of latent fingerprint development were discussed in detail. It was summarized that the optical property of the nanomaterials had great effects on the developing contrast, the morphology and size of the nanomaterials had great effects on the developing sensitivity, and the adsorption performance and surface characteristic of the nanomaterials had great effects on the developing selectivity. At the end of this review, we also put forward some prospects for the nanomaterial-based development of latent fingerprints. From the perspective of developing materials, the nanomaterials should be involved in the transition from single luminescent property to multiple luminescent properties, from direct use of available nanomaterials to elaborate control of particle morphology and size, from simple surface treatment to targeted molecule modification, from toxic materials to non-toxic materials. From the perspective of developing strategies, the methods should be involved in the transition from strong background noise to weak fluorescent interference, from clear visualization of minutiae to distinct development of sweat pores, from physical adsorption mechanism to targeted molecule recognition, from effective development of trace evidence to nondestructive detection of biological evidence. While only focusing on improving the effects of fingerprint development, we also suggest researchers pay more attention to the evaluation of development effects, which will greatly promote fingerprint development techniques to play an important role in forensic sciences.