Capillaries locally stiffen their surroundings as they grow
A collaboration with Professor Andrew Putnam, University of Michigan
The following reflection confocal microscopy video shows a HUVEC-derived capillary invading a 3-D fibrin hydrogel. Notice the local deformations to the matrix as the tip cell contracts. We aim to determine the local resistance to such deformations, and the work generated by the cell:
We use optical tweezers active microrheology (AMR) to map thestiffness of the Extra Cellular Matrix (ECM) surrounding invading capillary
To accomplish AMR, we embed a dispersion of microbeads within the fibrin tissue. The video below shows a capillary in fibrin with a single microbead exhibiting a gorgeous diffraction pattern visible in this reflection mode of imaging (The bead appears as a circle surround by concentric diffraction rings. If the capillary points to ‘twelve o-clock’, then the bead is near the tip of capillary, at 9:00). If you look carefully you can see the cell pluck a single fiber in front of the capillary (at time = 15 sec).
KEEP AN EYE OUT FOR OUR PUBLICATION – MANUSCRIPT UNDER REVIEW (AS OF SEPT 24, 2017)
We have exciting results not to be published on our website yet.
Relevant papers:
E. Kniazeva; J.W. Weidling; R. Singh; E.L. Botvinick; M.A. Digman; E. Gratton; A.J. Putnam
Quantification of local matrix deformations and mechanical properties during capillary morphogenesis in 3D
Integrative Biology. 4 (4), 431-439.
M.A. Kotlarchyk; S.G. Shreim; M.B. Alvarez-Elizondo; L.C. Estrada; R. Singh; L. Valdevit; E. Kniazeva; E. Gratton; A.J. Putnam; E.L. Botvinick
Concentration independent modulation of local micromechanics in a fibrin gel.
PLoS One. 6 (5), e20201.