Designing allostery-inspired response in mechanical networks*

Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds [1-3]. We have extended this idea to tune more general properties of networks [4]. Inspired by the long-range coupled conformational changes that constitute allosteric function in proteins, we can produce a strain between any two target nodes in a network in response to an applied source strain on a distant pair of nodes by removing only ∼1% of the bonds. Moreover, we can also control multiple pairs of target nodes, each with a different individual response, from a single source, and tune multiple independent source/target responses simultaneously. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.
[1] “The principle of independent bond-level response: tuning by pruning to exploit disorder for global behavior,” C.P. Goodrich, A.J. Liu, S.R. Nagel PRL 114, 225501 (2015).
[2] “Role of local response in manipulating the elastic properties of disordered solids by bond removal,” D. Hexner, A.J. Liu, S.R. Nagel: arXiv:1708.07207
[3] “Auxetic metamaterials from disordered networks,” D.R. Reid, N. Pashine, J.M. Wozniak, H.M. Jaeger, A.J. Liu, S. R. Nagel, J.J. de Pablo: arXiv: 1710.02493
[4] “Designing allostery-inspired response in mechanical networks,” J.W. Rocks, N. Pashine, I. Bischofberger, C.P. Goodrich, A.J. Liu, S.R. Nagel PNAS 114, 2520 (2017).