Ian Wark Research Institute, University of South Australia, Adelaide, Australia.
J Hosp Infect. 2010 Nov;76(3):234-42. doi: 10.1016/j.jhin.2010.07.001. Epub 2010 Sep 17.
Established methods for cleaning and sterilising biomedical devices may achieve removal of bioburden only at the macroscopic level while leaving behind molecular levels of contamination (mainly proteinaceous). This is of particular concern if the residue might contain prions. We investigated at the molecular level the removal of model and real-life proteinaceous contamination from model and practical surfaces by air plasma (ionised air) treatment. The surface-sensitive technique of X-ray photoelectron spectroscopy (XPS) was used to assess the removal of proteinaceous contamination, with the nitrogen (N1s) photoelectron signal as its marker. Model proteinaceous contamination (bovine serum albumin) adsorbed on to a model surface (silicon wafer) and the residual proteinaceous contamination resulting from incubating surgical stainless steel (a practical biomaterial) in whole human blood exhibited strong N1s signals [16.8 and 18.5 atomic percent (at.%), respectively] after thorough washing. After 5min air plasma treatment, XPS detected no nitrogen on the sample surfaces, indicating complete removal of proteinaceous contamination, down to the estimated XPS detection limit 10ng/cm(2). Applying the same plasma treatment, the 7.7at.% nitrogen observed on a clinically cleaned dental bur was reduced to a level reflective of new, as-received burs. Contact angle measurements and atomic force microscopy also indicated complete molecular-level removal of the proteinaceous contamination upon air plasma treatment. This study demonstrates the effectiveness of air plasma treatment for removing proteinaceous contamination from both model and practical surfaces and offers a method for ensuring that no molecular residual contamination such as prions is transferred upon re-use of surgical and dental instruments.
用于清洁和消毒生物医学设备的既定方法可能仅在宏观水平上实现生物负荷的去除，而在分子水平上仍存在污染（主要是蛋白质）。如果残留物可能含有朊病毒，则尤其令人关注。我们通过空气等离子体（电离空气）处理，在分子水平上研究了从模型和实际表面去除模型和实际蛋白质污染的情况。我们使用表面敏感的 X 射线光电子能谱（XPS）技术来评估蛋白质污染的去除情况，其标志物是氮（N1s）光电子信号。模型蛋白质污染（牛血清白蛋白）吸附在模型表面（硅片）上，而在整个人类血液中孵育手术不锈钢（实际生物材料）后残留的蛋白质污染显示出很强的 N1s 信号[分别为 16.8 和 18.5 原子百分比（at.%）]，即使经过彻底清洗也是如此。经过 5 分钟的空气等离子体处理后，XPS 在样品表面上未检测到氮，表明蛋白质污染已完全去除，降至估计的 XPS 检测限 10ng/cm(2)。对经过临床清洁的牙科钻头进行相同的等离子体处理后，观察到的 7.7at.%氮减少到反映新钻头的水平。接触角测量和原子力显微镜也表明，空气等离子体处理后，蛋白质污染完全从分子水平上被去除。这项研究表明空气等离子体处理对于从模型和实际表面去除蛋白质污染是有效的，并提供了一种方法，可以确保在重新使用手术和牙科器械时不会转移任何分子残留污染，例如朊病毒。
