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Depyrogenation by Inactivation and Removal
Published in James Agalloco, Phil DeSantis, Anthony Grilli, Anthony Pavell, Handbook of Validation in Pharmaceutical Processes, 2021
Karen Zink McCullough, Allen Burgenson
As part of their life cycle, and especially in response to the harsh environments often found in pharmaceutical manufacturing facilities, gram-negative bacteria produce “buds” or microspheres of outer membrane constituents called Outer Membrane Vesicles, or OMV (Brogden and Phillips, 1988; Ellis et al., 2010; Bonnington and Kuehn, 2016.) These OMVs cannot replicate and therefore are not viable, but they can contain the same LPS constituents that were part of the cell membranes from their “parent” organisms or LPS that is displaced as the result of adaptation. The size of OMVs range from 20–250 nm, so they will easily pass through a 0.22 μm sterilizing filter (Schwechheimer and Kuehn, 2015; Figures 17.4A and 17.4B). The methods used to destroy or eliminate live microbes such as autoclaving or sterile filtration may kill or remove whole bacterial cells and autoclaving may destroy OMVs, but any cell wall fragments or OMVs that remain after these processes may still contain active endotoxins. Note, as well, that current research suggests that there is no evidence that LPS monomers from the outer leaflet exist in nature (Ellis et al., 2010).
Cell membrane-cloaked bioinspired nanoparticles: a novel strategy for breast cancer therapy
Published in Journal of Dispersion Science and Technology, 2023
Anuja Muley, Abhijeet Kulkarni, Prajakta Mahale, Vishal Gulecha
Gram-negative bacteria continuously release nanosized, bilayered, spherical proteoliposomes called outer membrane vesicles (OMVs). These OMVs have low immunogenicity and can specifically target and kill cancer cells [44–45]. Bacterial membrane extraction differs from that of other cells due to the presence of peptidoglycans as well as the cell membrane in their structure. OMVs can be directly collected and engineered as nanovesicles [46].