Question

Please Read the article “Cell movement is guided by the rigidity of the substrate” by Lo et al. (Biophys J, 2000) to help answer

Question 1: Link to article: https://www.sciencedirect.com/science/article/pii/S0006349500762795#!

Q1) What is the hypothesis of the paper and what is the paper trying to investigate?

Answer 1

The paper "Cell movement is guided by the rigidity of the substrate" by Lo et al. 2000, is based on the hypothesis that cells are capable of responding to rigidity of substrate through tactile (touch) exploration process. in this process, cells exert some contractile forces on the substrate and then interpret the substrate deformation (by means of receptors) and then decide the preffered direction of movement or locomotion.

In this paper the authors are trying to investigate the mechanism of how cell movement is directed by the rigidity of the substrate. For that purpose, they designed an experiment with Health 3T3 fibroblasts on flexible polyacrylamide sheets coated with type I collagen. The change in rigidity was introduced in the polyacrylamide sheet by a discontinuity in the concentration of the bis-acrylamide cross-linker.

It was observed that the cells on approaching the transition zone (soft zone) showed easy migration across the boundary of the substrate with a concurrent increase in spreading area and traction forces. However, the cells towards the stiff side (hard side) moved back or retracted form the boundary of the substrate. Here the authors therefore concluded that changes in the turidity of tissues could prove to be important   for controlling a number of routine as well as pathological processes viz aviz locomotion.