NatWi - Indrajit Maity

Molecular Robotics Powered by Enzyme Reaction Network to Actuate Supramolecular Self-assembly

One of the central challenges is to amplify the function of molecular machines into mesoscopic and macroscopic dimension to create work. At best this requires organizing the machines so as to be able to harness their motion with a directionality. In this context, molecular self-assembly is one of the key steps. Keeping this in mind we proposed the temporal control over self-assembly processes as modulated by a synthetic molecular robot unit. Further, we dedicated to developing an autonomous robotic action to mimic the natural dissipative system towards designing transient supramolecular nanostructures and materials. The key towards autonomous operation in pH-switchable structures is to

use latent chemical fuels (dormant promoter/deactivator) that form chemical reaction networks, and which can pre-orchestrate pH profiles that develop autonomously after injection of the fuels. The promoter will be the esterase activity on ethyl acetate to produce acid whereas the dormant deactivator will be pH-dependent urease-catalyzed conversion of urea into CO₂ and NH₃ producing base in the system. The autonomous environment changes (pH) allow the robotic bolaamphiphile to organize alternatively into its contracted or extended conformations and thereby, it will allow us to control the transient self-assembly process on demand. In our first approach, we have elaborately studied the feedback controlled enzymatic reaction networks, topology, kinetics and reaction dynamic. Intriguingly, we have observed interesting non-linear networks responses in compartmentalized reaction networks vs free network in solution. The compartmentalized enzyme reaction network into a polymer gel sphere is shown to utilize as the miniaturised factory to generating pH-front guiding the supramolecular self-assembly process and alignment of evolved nanostructures. In the next approach, we intend to apply this enzyme reaction networks into our designed robotic bolaamphiphiles to control the self-assembly and material contraction-expansion studies. The combination of self-assembly, molecular machines and enzyme reaction networks will play a significant role towards future applications in soft robotics, catalysis, medicinal science, systems chemistry and nanotechnology. Therefore, this can offer promising aspects in the development of next generation molecular materials.