Directed Biomineralization: Designing Peptides to Control Crystal Nucleation and Growth

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Non-technical: This award by the Biomaterials program in the Division of Materials Research to Johns Hopkins University is in developing fundamental materials research into the processes by which proteins control mineral nucleation and growth. Inspired by biological organisms that have the impressive ability to craft exquisite solid materials such as spiraled shells and internal skeletons, the aim is to characterize and utilize biological material-building strategies. The investigator seeks to understand crystal growth mechanisms and their interplay with adsorbed biomolecules, such that one might eventually use peptides to direct the growth of solid nanomaterials, for example for energy storage applications or advanced medical or structural materials. Design of custom materials, enabled by this basic research, will be transformative for manufacturing, especially in nanotechnology, sensing, energy, medicine, and anti-biofouling. The computational algorithms will be distributed broadly and made accessible through a web gateway. The PI will train a graduate student in cross-disciplinary studies in chemical engineering, biophysics, nanotechnology and materials science. Protein structure prediction and design teaching modules will be expanded to include biomineralization. Outreach will include weekly team visits to a local elementary school for an after-school STEM program, piloting of an intern program focused on women in computing, and the involvement of a high school student as a summer intern. Technical: This project will tie together thermodynamic and kinetic theories of crystal nucleation and growth with computational and experimental methods by experimentally testing computationally designed peptides that are optimized to guide calcium carbonate growth. Following a design cycle that alternates computational design and prediction with experimental observation, results will accelerate the discovery of how proteins interact with surfaces, how peptides can guide heterogeneous nucleation, how adsorbates affect mineral growth, and how these phenomena can be harnessed to create atomically-assembled materials and structures. New peptides will be tested through a progressive hierarchy of experimental measurements probing nucleation ability, binding affinities, step velocities, and biomineral habit. At each stage, the experiments will provide data to inform the computational model. In effect, this work will drive a feedback loop of computational design and experiments, narrowing the field of possible interactions to those supported by the experimentation. The combination of experiments and computations on dozens of related peptide designs will provide an extensive molecular-scale picture of adsorbate-controlled mineralization. These data will provide new benchmarks for energy functions and new insights into protein-surface interactions and modeling in general, leading to improvements in overall understanding of nucleation, adsorption, crystal growth, materials synthesis, and molecular engineering.