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Epitaxial Growth of Metal Organic Frameworks

58:41 recording · AUTO · 4 speakers

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Brief overview

Two papers show physical nanospikes killing biofilm bacteria and microgravity driving new phage-host evolution aboard the ISS.

  1. Nanospikes kill by physics, not chemistryThe spike punches the membrane instead of being metabolised, so the surface stays continuously active rather than needing repeated disinfection.
  2. Sprinkled MOFs beat embedded onesDrop casting the spiky iron frameworks onto a substrate gave better coverage, and therefore better killing, than casting them in situ.
  3. Microgravity delays infection but forces evolutionPhage activity stalled past four hours in orbit, yet by day 23 both phage and host had picked up de novo mutations absent from ground controls.
Executive Summary AI
  • Petra Levin opens with an ASM review by Madeline Barron, "Piercing Pathogens, a New Anti-Biofilm Strategy", framing biofilms as a problem for medical implants, water pipes and ship hulls that needs surfaces which stop bacteria physically rather than chemically.6:00
  • The idea traces to Elena Ivanova at Royal Melbourne Institute of Technology, who over a decade ago dipped a cicada wing in a Pseudomonas aeruginosa suspension and found the bacteria impaled on natural nanospikes and dead.7:50
  • The Gothenburg and Chalmers group (Cao, Pandit and colleagues) built iron-based metal organic framework "caltrops" and found that drop-casting them onto a surface like sprinkles gave better coverage and better killing of E. coli than embedding them during manufacture, with cells either pierced or squeezed to death.15:38
  • Michael Schmidt then presents a PLOS Biology paper from the Raman lab at UW Madison in which bacteriophage T7 and non-motile E. coli BL21 were co-cultured in sealed cryovials on the ISS at MOIs of 10 to the minus 6 and 10 to the minus 4, with no rise in phage titer in the first four hours but a four-log increase by day 23 plus de novo mutations in both partners.26:28
  • The most practical result is that the space-evolved phages were better at killing drug-resistant uropathogenic E. coli back on Earth, suggesting microgravity could act as a new laboratory for phage-therapy discovery.50:20
Key Quote
“Not only were they not happy, they were incapable of being either happy or sad.”
— Petra Levin8:57
Key Quote
“But in microgravity, everything slows down.”
— Michael Schmidt27:20
Key Quote
“Well, the same would happen to bacteria, but you could do it very much faster with viruses, right?”
— Vincent Racaniello46:00