Membrane-induced eggshell biomineralization towards controllable crystallization

The avian eggshell is an extreme example of rapid biomineralization, yet how its underlying substrate, the eggshell membrane (ESM), initiates this process remains elusive, and the application potential of this fundamental biological mechanism has yet to be explored. Across the 33 avian species examined, ESMs consistently promoted CaCO3 crystallization under standardized in vitro conditions and exhibited low heterogeneous nucleation barriers. Inspired by this mechanism, we designed a biomimetic fibrous membrane (b-FM) that reproduces the structural and chemical features of natural ESMs. The b-FM achieves a deposition rate of 0.58 mg cm−2 day−1, surpassing the fastest natural ESM (0.46 mg cm−2 day−1). This efficiency arises from a threefold synergistic mechanism: (1) strong negative surface potential promoting Ca2⁺ accumulation, (2) reduced heterogeneous nucleation energy barrier, and (3) regulated crystallization pathways. Demonstrating its application potential, a b-FM/glass fiber mesh (b-FM/GF) composite module was employed for water softening in a circulating cooling-water system. In a 30-day continuous circulation experiment, the b-FM/GF-treated system maintained softened water quality and effectively suppressed pipe scaling, with less than 2% reduction in the effective pipe area. These findings reveal shared features of ESM-promoted mineralization and establish design principles for industrial crystallization control.