1：Experimental Design and Method Selection:

The study involved structural analysis of snow crab shells using microscopy and spectroscopy techniques, followed by biomimetic transformations to replicate the structure in various materials. Methods included decalcification, deacetylation, calcination, carbonization, phosphatization, and fluoridation.

2：Sample Selection and Data Sources:

Cooked and uncooked snow crabs (Chionoecetes opilio) from the Atlantic Ocean were obtained from local grocery stores. Samples were prepared by removing proteins and minerals to isolate chitin and chitosan membranes.

3：List of Experimental Equipment and Materials:

Equipment included SEM (Hitachi S4700, Hitachi S-2600), POM (Olympus BX41), CD spectropolarimeter (JASCO J-710), UV-vis spectrophotometer (Cary 5000), solid-state NMR (Varian Unity Inova 400 MHz), PXRD (D8 Advance), XPS (Leybold MAX200), FT-IR (Nicolet 6700), Raman spectrometer (SpectraCode RP-1), TGA (PerkinElmer Pyris 6), nitrogen sorption analyzer (Micromeritics ASAP 2020), hardness tester (Buehler High Quality Hardness Tester). Chemicals included ammonium hydrogen phosphate, sodium fluoride, sodium hydroxide, hydrochloric acid, and glyoxal.

4：Experimental Procedures and Operational Workflow:

Procedures involved treating crab shells with NaOH and HCl to remove proteins and minerals, followed by deacetylation to produce chitosan. Calcination at 500°C produced calcite replicas. Carbonization under nitrogen at 600°C followed by acid etching produced nitrogen-doped carbon. Hydrothermal phosphatization and fluoridation were used to create apatite and fluorapatite/chitin composites. Characterization was performed using various spectroscopic and microscopic techniques.

5：Data Analysis Methods:

Data analysis included SEM imaging, POM observation, CD and UV-vis spectroscopy, solid-state NMR, PXRD, XPS, FT-IR, Raman spectroscopy, TGA, nitrogen sorption isotherms, elemental analysis, and hardness testing.