The first fully synthetic polymer‐based approach for red‐blood‐cell cryopreservation without the need for any (toxic) organic solvents is reported. Highly hydroxylated block copolymer worms are shown to be a suitable replacement for hydroxyethyl starch as a extracellular matrix for red blood cells. When used alone, the worms are not a particularly effective preservative. However, when combined with poly(vinyl alcohol), a known ice‐recrystallization inhibitor, a remarkable additive cryopreservative effect is observed that matches the performance of hydroxyethyl starch. Moreover, these block copolymer worms enable post‐thaw gelation by simply warming to 20 °C. This approach offers a new solution for both the storage and transport of red blood cells and also a convenient matrix for subsequent 3D cell cultures.
A structurally simple synthetic polymer based on alternating charged side chains is designed and synthesised to mimic antifreeze proteins. The polymer is found to enhance the cryopreservation of red blood cells.
Antimicrobial
resistance is a global healthcare problem with a
dwindling arsenal of usable drugs. Tuberculosis, caused by Mycobacterium tuberculosis, requires long-term combination
therapy and multi- and totally drug resistant strains have emerged.
This study reports the antibacterial activity of cationic polymers
against mycobacteria, which are distinguished from other Gram-positive
bacteria by their unique cell wall comprising a covalently linked
mycolic acid–arabinogalactan–peptidoglycan complex (mAGP),
interspersed with additional complex lipids which helps them persist
in their host. The present study finds that poly(dimethylaminoethyl
methacrylate) has particularly potent antimycobacterial activity and
high selectivity over two Gram-negative strains. Removal of the backbone
methyl group (poly(dimethylaminoethyl acrylate)) decreased antimycobacterial
activity, and poly(aminoethyl methacrylate) also had no activity against
mycobacteria. Hemolysis assays revealed poly(dimethylaminoethyl methacrylate)
did not disrupt red blood cell membranes. Interestingly, poly(dimethylaminoethyl
methacrylate) was not found to permeabilize mycobacterial membranes,
as judged by dye exclusion assays, suggesting the mode of action is
not simple membrane disruption, supported by electron microscopy analysis.
These results demonstrate that synthetic polycations, with the correctly
tuned structure are useful tools against mycobacterial infections,
for which new drugs are urgently required.
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