Programmed synthesis of mesoporous protein crystals in cellular reactors

Protein crystals are mesoporous materials derived from nature, known for their versatility in structure and physicochemical properties. Conventional in vitro synthesis relies on metastable crystallization and often lacks controllability and programmability. Here, we present an in cellulo synthesis platform for controllable and programmable protein crystallization. We showed that, following initial nucleation, crystal growth is governed by the steady protein expression, enabling predictable and tunable growth dynamics. Leveraging this property, we integrated HaloTag and click chemistries to achieve modular and programmable immobilization of diverse guest materials with precise nanoscale spatial patterns. Furthermore, we demonstrated the sequential release of immobilized materials in physiologically relevant fluids. As a proof-of-concept, we programmed particles to carry human fibroblast growth factors in distinct layers, which induced oscillatory Akt signaling of designed patterns in cell culture. This platform opens new avenues for the programmable production of mesoporous materials, with promising applications in catalysis, biomedicine, and beyond.