2nd of April 2015, Chichley Hall
Nikolaj Gadegaard introduced the concept of high content high throughput screening for effective nanotopographies charting the development of fabrication. The primary tool that allows full design control is an electron beam lithography tool (in Glasgow at the James Watt Nanofabrication Centre that is a Leica VB6, which is soon to be accompanied by a Nanobeam III). He has worked on speeding up writing times by factors of >>20; and introduced as well as optimised replication techniques that have increased in speed such that now 100s of samples can be made by injection moulding in an afternoon whereas with nanoimprint lithography. A recent development is the possibility to create nanopillars with a high aspect ratio using cirlex inserts in injection moulding that allow to "pull" the pillars into nanowhiskers, whilst the tool separates from the moulded part. These pillars are "soft" in the sense that cells can deform them, that way the forces that cells exert onto the surface can be measured.Exciting as that will allow for the forces that are modified in differentiating stem cells, when they sit on patterns (e.g. the "famous" NSQ50) to be measured and correlated to e.g. nuclear deformation, or the shape of focal adhesions. When embryonic stem cells cultivated on the soft nanowhiskers the softer ones improve the differentiation towards pancreatic beta cells.
The other part of the talk centred on pattern hunting - as ever since the first nanopatterns were made the cellular responses have always been cell type dependant, e.g. fibroblatss needing a higher step cue (200nm) to follow than epithelia (100nm) or macrophages (20nm). Here the making of gradient patterns with a constantly varying depth (and/or groove width) allows to look for 'hot spots" of responsiveness. In combination with high content imaging (Cell profiler & Cell Analyst) the cellular response can be quantified in depth. The other approach has been to develop an 18 well platform to screen for 'hits'. In extension there was a hint at the future looking at focal adhesions using super resolution microscopy to investigate the difference between square (maintaining stemness) and near square ±50nm (promoting bone differentiation) patterns.
More about Nikolaj Gadegaard: http://www.gla.ac.uk/schools/engineering/staff/nikolajgadegaard/
This talk was part of a workshop on "Cell Mechanobiology" organised by Rene de Borst, which took place April 1st and 2nd 2015, with support by the Royal Society at Chicheley Hall. for the programme details see: http://bio-mat-sketches-mor.blogspot.co.uk/2015/04/cell-mechanobiology-workshop-1st-2nd.html