Hydroxyapatite deposition on molecular assemblies of a porphyrin derivative under body fluid conditions

抄録

Biomimetic mineralization is useful to deposit biominerals on various organic scaffolds under mild conditions. This study investigated the use of molecular self-assemblies as scaffolds for hydroxyapatite (HAp) deposition under body fluid conditions. We also evaluated the scaffold assembly structures during mineralization. A porphyrin derivative having carboxylic acid groups (TCPP) was adsorbed from buffer solutions onto solid substrates to form TCPP self-assemblies. The resulting substrates were then immersed in 1.5SBF, a solution having 1.5 times higher inorganic ion concentrations than those of simulated body fluid (SBF). They were then incubated at 36.5°C. The obtained samples’ surfaces were examined using various physical characterizations such as scanning electron microscopy, FT–IR spectroscopy, and thin-film X-ray diffraction. Furthermore, the samples’ surfaces were monitored spectroscopically during HAp deposition, particularly addressing the Soret band peaks of TCPP assemblies that are sensitive to TCPP assembly structures. Results showed that the TCPP assemblies formed on 2-aminoethanethiol-modified solid substrates induced heterogeneous nucleation and growth HAp on their surfaces while maintaining their J-aggregate structures. No marked effect was observed for TCPP assembly structures during HAp deposition when polyelectrolyte thin films were introduced as a soft layer between the TCPP assemblies and solid substrates, which supported the structural rigidity of the TCPP assemblies against HAp formation thereon.