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The Langmuir–Blodgett (LB) films of zinc(II)5,10,15,20-tetra[4-oxy(2-stearic acid) porphyrin] (ZnTSPP) was used as ordered molecular template to induce the growth of calcium phosphate crystals. This process at the surface of LB films was monitored in situ by Inverted Phase Contrast Microscopy (IPCM). It was found that the crystal morphologies changed from amorphous to regular crystal with the prolonging of the time. The transformation from unstable octacalcium phosphate (OCP) to the most stable hydroxyapatite (HAp) was confirmed. This process is step by step, which is different from the traditional epitaxial process.

Inverted phase-contrast microscopy has been successfully used to observe in situ the growth of hydroxyapatite (HAp) from pseudophysiological solution under dipalmitoylphosphatidylcholine (DPPC) monolayer. The results showed that the DPPC monolayer template could control the sizes, orientation and morphology of the formed HAp crystals effectively. The HAp spherical particles with the diameters of 0.4–0.8 μm were formed beneath the DPPC monolayer after 7 days. The structure and component of HAp were investigated by transmission electron microscopy and electronprobe microanalyzer. The HAp crystallization process is controlled predominantly by electrostatic interactions between the template and HAp.

The biomimitic growth of hydroxyapatite (HAp) on the surface of collagen membrane soaked in 1.5× simulate body fluid (SBF) solution was observed in situ by phase-contrast microscopy. The nucleation of HAp was very slow at the initial stage (first 3 days) on the surface of collagen. After an incubation period, the growth of HAp crystals occurred quickly. The negatively charged carboxylate groups of collagen surface are responsible for the deposition of HAp. This deduction was confirmed by the red shifts of stretching vibration band of carboxylate groups of collagen molecules in Fourier transform infrared spectroscopy (FTIR) spectra. The crystallographic structure of HAp/collagen composite was studied by FTIR spectroscopy, X-ray diffraction (XRD) and electron probe microanalyzer (EPM). This composite material of HAp/collagen may be applicable for use as a bone substitute.

The structures of the aqueous solutions of sodium formate and lithium formate are studied according to the growth conditions of the crystals under different supersaturations and temperatures by Raman spectroscopy. The effects of temperature, concentration, supersaturation and cation on the structures of solutions and the structure difference between lithium formate solution and lithium formate monohydrate crystal are analyzed. The result shows that the concentration, temperature and supersaturation effect the structures of the solutions slightly and the cation effects the frequency of the bands greatly.