Investigating elemental distribution and crystalline structure with high spatial resolution in nemertean stylet Amphiporus lactifloreus

Our research focuses on the biological design principles of nemertean worm Amphiporus lactifloreus, specifically its stylet—a vital tool for prey capture. The primary stylet, measuring 100 µm in length, is composed of stable amorphous calcium phosphate (ACP), a precursor phase that in other organisms is transient and transforms into crystalline calcium phosphate phases like hydroxyapatite, found in human bones and teeth. We employ synchrotron experiments with nanometre resolution (ID13-WAXS+SAXS, ID21-µ-XANES) to investigate the ACP phase's structure, potential amorphous phases, and stabilization mechanisms. Preliminary lab results, using nano-CT and Energy Dispersive Spectroscopy, show notable differences in contrast and elemental distributions. This knowledge is crucial for synthesizing ACP and ACP-based materials with applications in hard tissue engineering, such as bone and teeth repair.

本研究聚焦于纽形动物（Nemertean worm）物种乳突扁额纽虫（Amphiporus lactifloreus）的生物学设计原理，特别是其用于捕食的关键器官——吻针（stylet）。该主吻针长度为100 µm，由稳定的无定形磷酸钙（ACP, amorphous calcium phosphate）构成；而在其他生物体内，无定形磷酸钙属于瞬态前驱相，可转变为结晶态磷酸钙物相，例如存在于人类骨骼与牙齿中的羟基磷灰石（hydroxyapatite）。我们采用纳米分辨率同步辐射实验技术，涵盖ID13-WAXS+SAXS（广角X射线散射+小角X射线散射）、ID21-µ-XANES（微米级X射线吸收近边结构），以探究无定形磷酸钙物相的结构、潜在无定形物相及其稳定化机制。借助纳米计算机断层扫描（nano-CT）与能量色散谱（Energy Dispersive Spectroscopy）获得的初步实验室结果显示，该吻针的衬度与元素分布存在显著差异。该研究成果对于合成无定形磷酸钙及其基复合材料具有关键价值，这类材料可应用于硬组织工程领域，例如骨与牙齿修复。