Albumin Conformational Change and Aggregation Induced by Nanostructured Apatites
Biomaterials with nanostructured surfaces influence cellular response in a significantly different, and often beneficial, manner compared to materials with coarser features. Hydroxyapatite [HA, Ca10(PO4)6(OH)2] and strontium-apatite [Sr10(PO4)6(OH)2] microspheres that present nanotopographies similar to biological apatites were incubated in albumin solutions, at physiological conditions (40 mg ml-1; 37 °C), for up to 72 h. Electronic and vibrational circular dichroism spectroscopies revealed spectral signatures characteristic of stacked β-sheet regions in higher ordered structures (e.g., fibrils). The presence of stacked β-sheets was further evidenced by thioflavin T staining. The sequestration of interfacial Ca atoms by pyrophosphate ions (P2O7 4-), prior to albumin adsorption, prevented stacked β-sheet formation on hydroxyapatite. These results suggest that the charge and/or spatial arrangement of Ca atoms direct stacked β-sheet formation during bovine serum albumin adsorption. Stacked β-sheet spectral features were also observed after incubating HA in fetal bovine serum, highlighting that this phenomena could direct cellular response to these biomaterials in vivo.
K. P. Fears et al., "Albumin Conformational Change and Aggregation Induced by Nanostructured Apatites," Biointerphases, vol. 12, no. 2, pp. 02D403-1-02D403-11, American Institute of Physics (AIP), Jun 2017.
The definitive version is available at https://doi.org/10.1116/1.4982641
Materials Science and Engineering
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