Amorphous 1-D nanowires of calcium phosphate/pyrophosphate: A demonstration of oriented self-growth of amorphous minerals

Chaobo Feng, Bing-Qiang Lu, Yunshan Fan, Haijian Ni, Yunfei Zhao, Shuo Tan, Zhi Zhou, Lijia Liu, Jordan A. Hachtel, Demie Kepaptsoglou, Baohu Wu, Denis Gebauer, Shisheng He, Feng Chen

Research output: Contribution to journalArticlepeer-review


Amorphous inorganic solids are traditionally isotropic, thus, it is believed that they only grow in a non-preferential way without the assistance of regulators, leading to the morphologies of nanospheres or irregular aggregates of nanoparticles. However, in the presence of (ortho)phosphate (Pi) and pyrophosphate ions (PPi) which have synergistic roles in biomineralization, the highly elongated amorphous nanowires (denoted ACPPNs) form in a regulator-free aqueous solution (without templates, additives, organics, etc). Based on thorough characterization and tracking of the formation process (e.g., Cryo-TEM, spherical aberration correction high resolution TEM, solid state NMR, high energy resolution monochromated STEM-EELS), the microstructure and its preferential growth behavior are elucidated. In ACPPNs, amorphous calcium orthophosphate and amorphous calcium pyrophosphate are distributed at separated but close sites. The ACPPNs grow via either the preferential attachment of ∼2 nm nanoclusters in a 1-dimension way, or the transformation of bigger nanoparticles, indicating an inherent driving force-governed process. We propose that the anisotropy of ACPPNs microstructure, which is corroborated experimentally, causes their oriented growth. This study proves that, unlike the conventional view, amorphous minerals can form via oriented growth without external regulation, demonstrating a novel insight into the structures and growth behaviors of amorphous minerals.
Original languageEnglish
Pages (from-to)960-970
Number of pages11
Early online date13 Dec 2023
Publication statusPublished - 1 Mar 2024

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© 2023 Elsevier Inc. This is an author-produced version of the published paper. Uploaded in accordance with the University’s Research Publications and Open Access policy.


  • Amorphous inorganic solids
  • Nanowires
  • Calcium phosphate
  • Calcium pyrophosphate
  • Oriented growth

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