法医DNA实验室剪刀清洗和防污染探析

Scissors Cleaning and Preventing against Contamination in Forensic DNA Laboratory

目的探索一种法医物证检验过程中简捷有效的剪刀清洗方法。方法取50把洁净剪刀,用于重度污染(20把)和轻度污染(30把)模拟试验。在重度污染模拟组的每把剪刀刀刃处涂抹血液并于室温晾干后平均分为A、B两组,A组采用清洗机直接清洗,B组采用84消毒液浸泡后再以清洗机清洗;而轻度污染模拟组的30把洁净剪刀,以每把剪取血斑样本后平均分为C、D、E三组,C组用装有去离子水的喷壶喷洗刀刃,D组用酒精棉擦拭刀刃,E组不做任何处理。用植绒拭子擦拭所有剪刀刀刃,采用磁珠法提取DNA并实时定量,PCR复合扩增与毛细管电泳获取STR分型。结果B组除1例特殊情况外其余均未检出STR分型,D组均未获得完整STR分型,其余3组均获得部分或完整STR分型。结论84消毒液浸泡加清洗机清洗可以有效降低实验室剪刀污染。应杜绝重复使用剪刀且只能在样本确定的区域剪取。

Objective To explore a simple and effective method for scissors cleaning about examination of forensic evidential materials.Methods 50 pairs of clean scissors were taken into two simulation tests:one for heavy pollution(20 pairs)and the other for light pollution(30 pairs).For heavy pollution simulation,each pair of clean scissors were smeared with blood on inner sides of the two blades and allowed to dry at room temperature.Such 20 pairs of blood-smeared scissors were evenly allocated into two groups:A and B.Group A was cleaned directly with a cleaning machine while group B was immersed into a solution of 84 disinfectant before the machine cleaning.The 30 pairs of scissors for light pollution simulation were undergone with each pair to cut bloodstained gauzes,consequently having them averaged into three groups:C,D and E.Group C was rinsed with a sprayer containing deionized water while group D was wiped of every blade with alcohol cotton,yet having group E left for no treatment at all.All the tested scissors were wiped with fl ocking swabs from which DNA was extracted by way of magnetic beads for real-time quantifi cation.The STR genotyping was carried out with PCR amplifi cation and capillary electrophoresis.Results No STR genotyping was revealed in group B with only one unintentional exception while incomplete STR profi le was exposed in group D,with partial or totally complete STR profi le being uncovered in the other three groups.Conclusions 84 disinfectant immersion plus machine cleaning can effectively eliminate the contamination from forensic laboratory-used scissors.Every pair of scissors should not be used repetitively and had better shear only a certain designated zone with any evidential material.