Fibrinogen adsorption on hydroxyapatite, carbonate apatite and gold surfaces in situ detected by quartz crystal microbalance with resistance technique

When a biomaterial is implanted into the body, blood proteins adsorb on its surface and subsequently cells adhere via the protein adlayer. Thus, the understanding of protein adsorption and conformational change on the biomaterial surfaces is of great importance to control the biocompatibility such as antithrombotic properties and cell adhesion behaviors. In this study, we synthesized hydroxyapatite (HAp) and carbonate apatite (CAp) by a wet method. Then we successfully fabricated the HAp and CAp sensors for QCM-R by an electrophoretic deposition method. Adsorption behavior of proteins on the bone substitute material can be monitored by using these apatite sensors. Bovine serum albumin and fibrinogen were employed for the model proteins, and monitored the adsorption behavior on the HAp, CAp and reference gold (Au) sensors by the QCM-R technique. As a result, we revealed that fibrinogen and bovine serum albumin adsorbs on the gold surface by hydrophobic interaction, and adsorbs on the HAp and CAp surfaces mainly by electrostatic force. Besides, we revealed that fibrinogen adsorbs on the Au surface more rigid than on the HAp and CAp surfaces while bovine serum albumin adsorbs on the HAp and CAp surface more rigidly than on the Au surface.