Stem cell culture

June’s issue of Nature Materials has a focus on stem cell culture.  The first of three reviews discusses how various inherent properties of materials may be engineered to regulate stem cell decisions, while a second focuses on the influence of the nano scale extracellular environment on stem cell fate via integrin-matrix interactions.  The third review outlines progress in high-throughput materials discovery of growth substrates for large-scale human pluripotent stem cell culture.  A Perspective article discusses the interplay between soluble factors and physical microenvironment in the control of stem cell fate.  A variety of primary research articles and supporting “News and Views” pieces are also contained in the focus.  Worth a look.

http://www.nature.com/nmat/focus/cell-culture/index.html

Antibiotic AuPt nanoparticles

Researchers have discovered that bimetallic nanoparticles containing gold and platinum act as antimicrobial agents and are effective against a range of bacteria including E.coli, Salmonella Choleraesius and Pseudomonas Aeruginosa.  Pure gold or pure platinum nanoparticles were not antibiotic at all.  Investigations suggested two mechanisms in operation: disruption of the cell membranes and increased intracellular ATP.  The nanoparticles were not toxic to mammalian cells in vitro. 

Tuning the Composition of AuPt Bimetallic Nanoparticles for Antibacterial Applications, Y. Zhao et al, Angewandte Chemie International Edition, DOI: 10.1002/anie.201401035

http://onlinelibrary.wiley.com/doi/10.1002/anie.201401035/abstract 

Mechanics of lipid membranes

Researchers describe a method for investigating the viscosity of lipid membranes.  Tracers consisting of two microspheres coupled to a specific lipid allowed measurements of translational and rotational diffusion co-efficient and thus viscosity.  The method showed that adding vesicle trafficking protein Sar1p to membranes resulted in dramatic increase in membrane viscosity.

Measuring Lipid Membrane Viscosity Using Rotational and Translational Probe Diffusion; T.T. Hormel et al; Physical Review Letters; 112, 188101 (2014)

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.188101