无菌过滤

Sterile filtration is a unique sterilization method because it does not inactivate or kill microorganisms but rather physically removes them from a fluid (liquid or gas). The process relies on a membrane filter, a thin layer of semi-permeable material engineered with a specific pore size distribution. For sterilization, a filter with a nominal pore rating of 0.22 micrometers (µm) or smaller is typically used. This size is chosen based on the dimensions of the smallest known free-living bacteria, such as Brevundimonas diminuta, which is often used as the challenge organism for validating sterilizing-grade filters. As the fluid is forced through the filter by positive pressure or vacuum, the pores allow the fluid molecules to pass through but are small enough to trap bacteria and other microorganisms on the filter’s surface. The primary mechanism of retention is size exclusion, but other effects like electrostatic attraction and tortuous path interception can also contribute to capture. This method is indispensable for solutions containing heat-labile components, such as proteins, enzymes, 疫苗, and certain antibiotics, which would be denatured or destroyed by heat-based methods like autoclaving. It is considered a non-destructive sterilization technique. However, it has limitations. It cannot remove all viruses, as many are smaller than 0.22 µm, nor can it remove dissolved endotoxins or pyrogens. The process must also be conducted under aseptic conditions to prevent recontamination of the filtered fluid downstream of the filter.

过滤的历史 微生物 过滤技术可以追溯到19世纪末。1884年，路易·巴斯德的同事查尔斯·尚伯兰发明了尚伯兰过滤器，该过滤器由未上釉的瓷器制成。这一装置在早期病毒学研究中发挥了重要作用；德米特里·伊万诺夫斯基于1892年，马丁努斯·贝耶林克于1898年利用该过滤器证明，导致烟草花叶病的病原体比任何已知的细菌都要小，因为它能够穿过过滤器。他们将这类新型传染性病原体称为“可过滤病毒”。早期的过滤器虽然有效，但过滤速度慢且易碎。20世纪，随着由纤维素酯、尼龙和聚砜等材料制成的现代膜过滤器的出现，这项技术取得了显著发展。这些新材料使得制造孔径控制更精准、更耐用、流速更高的过滤器成为可能，从而使无菌过滤成为制药、生物技术以及食品饮料行业可靠且可扩展的工艺。