本文介绍一种适用于石头、混凝土块等硬质渗透性载体表面接触DNA检验的新方法。首先,将一定浓度的茚二酮荧光显现试剂喷涂在渗透性载体表面,使其与接触痕迹中的氨基酸反应,产生荧光物质,在高能量532nm激光（绿光,50万lx照度）照射下激发出荧光,从而定位接触痕迹。然后,利用负压吸附的方法定点吸附接触部位的脱落细胞,提取出脱落细胞的DNA,即接触DNA。在一起杀人案STR分型检验中,应用该方法在关键物证石头、混凝土块表面分别获得了嫌疑人各自单一的DNA分型。茚二酮荧光显现试剂结合高能量激光照射技术可对微量接触痕迹灵敏、准确地定位,将其用于对硬质渗透性载体表面接触DNA的检验,采取“定位-定点吸附-STR分析”的技术路线可大大减少工作量,有效提高单一个体DNA分型的检出率。

A new method was here introduced for detection of touch DNA on the hard and permeable objects (like stone, concrete block). First, 1, 2-indanedione, a special reagent which can react with amino acids to produce fluorescent substances, was sprayed on the hard and permeable objects. The 500000-lux illuminance, produc produced with an evidence-detecting laser device under 532nm laser, was to irradiate onto the 1, 2-indanedione-sprayed objects so that the strong fluorescence was excited from the fluorescent substances, exposing the exfoliative cells to be positioned. Then, the exfoliative cells were collected through a negative pressure absorption method and each of their DNA was extracted. Finally, STR analysis was carried out. In a homicidal case, the individual DNA typing of the suspects had been obtained from the respective surface of a stone and concrete block by the above method. The combination of 1, 2-indanedione detection reagent with high energy laser irradiation can locate the biological trace evidence with high sensitivity and accuracy. For touch DNA on the hard and permeable objects to be detected by the method established here, the adoption of “positioning-fixed-point absorption-STR analysis” can greatly reduce the workload and effectively improve the probability of obtaining individual DNA typing.