Evaluation of various cleaning methods to remove bacillus spores from spacecraft hardware materials.
Evaluation of various cleaning methods to remove bacillus spores from spacecraft hardware materials.
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评估从航天器硬件材料中去除芽孢杆菌孢子的各种清洁方法。
DOI：
10.1089/ast.2004.4.377
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发表时间：
2004
期刊：
影响因子：
4.2
通讯作者：
R. Kern
中科院分区：
文献类型：
--
作者：
K. Venkateswaran;Shirley Y. Chung;J. Allton;R. Kern
对用于清洁硬件表面的多种方法的生物清洁有效性进行了详细研究，其定义为去除细菌孢子的能力。铝（Al 6061）和钛（Ti 6Al-4V）被选择用于研究，因为它们被认为是最有可能用于航天器外星采样器建造的两种材料。对金属试样（1 cm x 2.5 cm）进行预清洁，并接种5.8 x 10（3）个可培养的枯草芽孢杆菌孢子，枯草芽孢杆菌孢子通常存在于航天器表面和组装环境中。随后使用以下方法清洁接种试样：（1）70%异丙醇擦拭;（2）水擦拭;（3）喷气推进实验室（JPL）使用的多溶剂飞行硬件清洁程序;（4）约翰逊航天中心开发的超纯水冲洗;和（5）商业半水多溶剂（SAMS）清洁工艺。通过琼脂平板试验、无菌试验（在液体培养基中生长）和落射荧光显微镜检查来测量生物清洁效果。测试的清洁方案均未完全清除铝表面的活孢子。相比之下，钛能够通过两种方法（JPL标准和商业SAMS清洁过程）清洁至无菌。进一步研究表明，JPL标准方法中采用的钝化步骤是两种金属的有效表面灭菌剂，但与铝不相容。建议将钛（Ti 6Al-4V）视为上级于铝（Al 6061），用于航天器采样硬件，因为其具有清洁灭菌的潜力，并且能够承受最有效的清洁方案。
A detailed study was made of the biological cleaning effectiveness, defined in terms of the ability to remove bacterial spores, of a number of methods used to clean hardware surfaces. Aluminum (Al 6061) and titanium (Ti 6Al-4V) were chosen for the study as they were deemed the two materials most likely to be used in spacecraft extraterrestrial sampler construction. Metal coupons (1 cm x 2.5 cm) were precleaned and inoculated with 5.8 x 10(3) cultivable Bacillus subtilis spores, which are commonly found on spacecraft surfaces and in the assembly environments. The inoculated coupons were subsequently cleaned using: (1) 70% isopropyl alcohol wipe; (2) water wipe; (3) multiple-solvent flight-hardware cleaning procedures used at the Jet Propulsion Laboratory (JPL); (4) Johnson Space Center-developed ultrapure water rinse; and (5) a commercial, semi-aqueous, multiple-solvent (SAMS) cleaning process. The biological cleaning effectiveness was measured by agar plate assay, sterility test (growing in liquid media), and epifluorescent microscopy. None of the cleaning protocols tested completely removed viable spores from the surface of the aluminum. In contrast, titanium was capable of being cleaned to sterility by two methods, the JPL standard and the commercial SAMS cleaning process. Further investigation showed that the passivation step employed in the JPL standard method is an effective surface sterilant on both metals but not compatible with aluminum. It is recommended that titanium (Ti 6Al-4V) be considered superior to aluminum (Al 6061) for use in spacecraft sampling hardware, both for its potential to be cleaned to sterilization and for its ability to withstand the most effective cleaning protocols.