preprint draft Andreas Ehrmann author eaa689ed-f6e0-11ea-865d-bd98cbcf83c20000-0002-0997-5678 Marija Krstić author a8f6d1c6-3200-11ee-973b-dab948eace26 Sahar Samadzadeh author 0099896b-5fb8-11ef-8420-b30b14627e93 Carl Peter Goodrich author EB352CD2-F68A-11E9-89C5-A432E66974250000-0002-1307-5074 CaGo department EdHa department AnSa department Functional bio-inspired nanomachines from sticky colloids project Many biological machines function through controlled conformational transitions, yet designing synthetic nanostructures with prescribed dynamical behavior remains a major challenge. Here, we develop a modular inverse-design framework for bistable nanostructures whose function is controlled by an energy profile along a geometric reaction coordinate. Inspired by proteins with rigid domains connected by flexible hinges, we introduce a hinge-arm paradigm in which a small bistable hinge controls the energetics of a conformational transition, while rigid arms map this transition onto the separation between external binding sites. Specifically, we ask which features of a target energy profile can be programmed under different design constraints. We find that the energy barriers and the binding-site separations in the two metastable states can be readily designed, while controlling the location of the transition state or the full shape of the energy profile requires additional design freedom. Using a differentiable design framework, we find that some optimized solutions are numerically inexact but still display the functional behavior for which the target profile was selected, emphasizing the importance of function-based evaluation criteria. These results establish a practical hierarchy of designability for bistable nanostructures and provide a route toward synthetic nanomachines that couple conformational transitions to target behavior. https://creativecommons.org/licenses/by-nc-nd/4.0/ 2026 eng 2606.3162010.48550/arXiv.2606.31620 https://research-explorer.ista.ac.at/record/22873 Ehrmann, A., Krstić, M., Samadzadeh, S., &#38; Goodrich, C. P. (n.d.). Designing bistable nanostructures for target behavior. <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.2606.31620">https://doi.org/10.48550/arXiv.2606.31620</a> A. Ehrmann, M. Krstić, S. Samadzadeh, and C. P. Goodrich, “Designing bistable nanostructures for target behavior,” <i>arXiv</i>. . Ehrmann, Andreas, et al. “Designing Bistable Nanostructures for Target Behavior.” <i>ArXiv</i>, doi:<a href="https://doi.org/10.48550/arXiv.2606.31620">10.48550/arXiv.2606.31620</a>. Ehrmann A, Krstić M, Samadzadeh S, Goodrich CP. Designing bistable nanostructures for target behavior. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.2606.31620">10.48550/arXiv.2606.31620</a> Ehrmann, Andreas, Marija Krstić, Sahar Samadzadeh, and Carl Peter Goodrich. “Designing Bistable Nanostructures for Target Behavior.” <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/arXiv.2606.31620">https://doi.org/10.48550/arXiv.2606.31620</a>. Ehrmann A, Krstić M, Samadzadeh S, Goodrich CP. Designing bistable nanostructures for target behavior. arXiv, <a href="https://doi.org/10.48550/arXiv.2606.31620">10.48550/arXiv.2606.31620</a>. A. Ehrmann, M. Krstić, S. Samadzadeh, C.P. Goodrich, ArXiv (n.d.). 228932026-09-09T13:19:13Z2026-09-11T07:37:58Z