Harris County Medical Examiner's Office, Houston, TX 77054, USA.
Forensic Sci Int Genet. 2010 Feb;4(2):89-94. doi: 10.1016/j.fsigen.2009.06.008. Epub 2009 Jul 22.
Laboratories employ various approaches to ensure that their consumables are free of DNA contamination. They may purchase pre-treated consumables, perform quality control checks prior to casework, and use in-house profile databases for contamination detection. It is better to prevent contamination prior to DNA typing than identify it after samples are processed. To this end, laboratories may UV irradiate or autoclave consumables prior to use but treatment procedures are typically based on killing microorganisms and not on the elimination of DNA. We report a systematic study of UV and autoclave treatments on the persistence of DNA from saliva. This study was undertaken to determine the best decontamination strategy for the removal of DNA from laboratory consumables. We have identified autoclave and UV irradiation procedures that can eliminate nanogram quantities of contaminating DNA contained within cellular material. Autoclaving is more effective than UV irradiation because it can eliminate short fragments of contaminating DNA more effectively. Lengthy autoclave or UV irradiation treatments are required. Depending on bulb power, a UV crosslinker may take a minimum of 2h to achieve an effective dose for elimination of nanogram quantities of contaminating DNA (>7250mJ/cm(2)). Similarly autoclaving may also take 2h to eliminate similar quantities of contaminating DNA. For this study, we used dried saliva stains to determine the effective dose. Dried saliva stains were chosen because purified DNA as well as fresh saliva are less difficult to eradicate than dried stains and also because consumable contamination is more likely to be in the form of a collection of dry cells.
实验室采用各种方法来确保其耗材不含有 DNA 污染。他们可能会购买预处理的耗材，在进行案例工作之前进行质量控制检查，并使用内部的档案数据库来检测污染。在进行 DNA 分型之前防止污染比在处理样本后发现污染更好。为此，实验室可能会在使用前对耗材进行紫外线照射或高压灭菌，但处理程序通常基于杀死微生物，而不是消除 DNA。我们报告了一项关于紫外线和高压灭菌处理对唾液中 DNA 持久性的系统研究。这项研究旨在确定从实验室耗材中去除 DNA 的最佳去污策略。我们已经确定了可以消除细胞物质中包含的纳克数量的污染 DNA 的高压灭菌和紫外线照射程序。由于高压灭菌可以更有效地消除污染 DNA 的短片段，因此比紫外线照射更有效。需要进行冗长的高压灭菌或紫外线照射处理。根据灯泡功率，UV 交联器可能需要至少 2 小时才能达到有效剂量，以消除纳克数量的污染 DNA（>7250mJ/cm²）。同样，高压灭菌也可能需要 2 小时才能消除类似数量的污染 DNA。在这项研究中，我们使用干燥的唾液斑来确定有效剂量。选择干燥的唾液斑是因为纯化的 DNA 以及新鲜的唾液比干燥的斑点更难消除，而且消耗品污染更可能以干燥细胞的形式存在。
