Nanobiotechnology for health-care

Self-sealing properties of phospholipid membranes after interactions with various nanostructures - MD study.
Raczynski P., Gorny K. and Dendzik Z.
Faculty of Science and Technology, University of Silesia in Katowice, 41-500 Chorzow, Poland
Email: przemyslaw.raczynski@us.edu.pl

Biological membranes are very effective barriers created by nature to protect the interior of the cell from impact of the outside environment. Although the membranes are designed to prohibit entrance of molecules into the cell, many researchers try to deliver various substances to the cell via phospholipid bilayer [1]. They try to discover less-invasive, efficient techniques of the targeted delivery of cargo, such as medicines or markers, to living cells. Significant effort is being done to study the characteristics of the use of nano-based materials as systems which are able to facilitate this task [2]. However, during the process of the cargo delivery to the cell, the phospholipid bilayer can not be permanently damaged because this is equivalent to cell death. To get deeper insight into the self-sealing process of the bilayer we have indented it with carbon and silicon-carbide nanotubes, graphene bilayers and silicon nanocones using non-equilibrium steered molecular dynamics (SMD) simulations [3,4]. After the indentation process the indenter was removed and the mechanism of self-sealing of the phospholipid bilayer was examined.
Our results show high abilities of the self-sealing of the cell membrane. These results can be useful as it is the essential problem when it comes to the potential application of nanostructures as nanocontainers for targeted drug delivery. The damage done to membrane can be quantified by the number of extracted lipids or membrane bending. To evaluate the effectiveness of self sealing and overall impact of indentation process on membrane integrity we performed additional series of computer simulations to assess the time necessary for the membrane to seal itself (expel water from its interior). Some additional factors, like nanostructure orientation toward membrane were also taken into account when analyzing the effectiveness of membrane self sealing after nanoindetation process. Our results suggest that carbon based nanotubes could be considered as effectors in targeted drug delivery or biosesnsors.
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 3.	Raczynski P., Gorny K., Beldowski P., et al. Application of Graphene as a Nanoindenter Interacting with Phospholipid Membranes-Computer Simulation Study // Journal of Physical Chemistry B-2020.-124,-P 6592-6602.
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