Abstract
Nanoscale molecular interactions between growing crystals and charged polyelectrolytes are crucial to understand the self-assembly of hierarchical organic–inorganic superstructures. Little is known about earth alkaline sulfate biominerals. Yet, a detailed understanding of bioinspired crystallization is crucial for developing general descriptors for bottom-up syntheses of complex ceramics. This study investigates biomimetic strontium sulfate (SrSO4) crystallization in the presence of poly(α-glutamic acid) using multiscale microscopy and vibrational spectroscopy. Using scanning electron microscopy, we observed doughnut-shaped spherulites with granular surface texture. Biomolecule inclusion led to pronounced peak broadening in synchrotron X-ray powder diffraction, wide-angle X-ray scattering, and Raman spectroscopy, commensurate with nanoscale domain sizes and pronounced lattice strain. Texture-like wide-angle X-ray scattering patterns and nanosized domains in transmission electron microscopy support the notion of mesocrystalline organization. Based on Z-contrast STEM imaging, intercalated organics are organized as elongated nanoclusters. Diffracting planes radiate outward from the crystal center, indicating a centrosymmetric strain field. The three-dimensional (3D) chemistry was investigated using atom probe tomography, which revealed a helical distribution of organic inclusions. This approach exemplifies how organic–inorganic templating can guide the evolution of intricate biomorphic crystal shapes. Round strontium sulfate crystals bear technological potential in the field of optoelectronics, such as IR–vis conversion materials or curved waveguides.
| Original language | English |
|---|---|
| Pages (from-to) | 62239-62250 |
| Number of pages | 12 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 17 |
| Issue number | 45 |
| DOIs | |
| State | Published - Nov 12 2025 |
Funding
VM is indebted to funding from the National Science Foundation (DMR-2137663). CDG thanks the Microscopy Society of America (MSA) and FAU’s Office of Undergraduate Research and Inquiry (OURI) for undergraduate research grants. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Dr Saul Lapidus is acknowledged for remote work at beamline 11-BM-B on general user proposal #72703. Work performed at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, was supported by the U.S. DOE, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. We thank Dr. Yuzi Liu and Dr. David Czaplewski for FIB/SEM training at CNM. We acknowledge Diamond Light Source (Didcot, U.K.) for time on beamline I-14 under the proposal MG34794 and access to the electron Physical Science Imaging Centre FIB/SEM instrument. We thank Dr. Anton Oleinik (FAU Geosciences) for providing access and technical support during polarized light microscopy. FIB milling and Transmission Electron Microscopy were conducted as part of user project CNMS2025-A-02920 at the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory.
Keywords
- biomineralization
- celestine
- mesocrystal
- morphogenesis
- organic templating
- organic−inorganic interface