Hierarchically porous carnosine-Zn microspheres

Hierarchically porous materials have broad applications in biotechnology and medicine, yet current fabrication methods often lack scalability and biocompatibility. Here, we present a peptide-coordination self-assembly approach to prepare hierarchically porous microspheres composed of naturally occurring carnosine dipeptide and coordinated Zn(II) ions. Metal coordination led to microsphere formation featuring interconnected channels with a hierarchically porous structure. Characterization with scanning electron and transmission electron microscopy, as well as with extended X-ray absorption fine structure, confirmed its nanofibrous architecture and local Zn(II) coordination environment. Liquid cell transmission electron microscopy, in turn, provided real-time insight into the assembly process, revealing a stepwise process from nanoclusters to nanofibers and ultimately to porous microspheres. The carnosine-Zn(II) microspheres exhibit intrinsic blue fluorescence and high porosity, containing both micropores and mesopores, which facilitate efficient mass transport and biomolecule immobilization. We leverage these properties to generate reusable, cell-free synthesis nanoreactors, to enhance DNA transcription and translation and protect against nuclease degradation.