Postoperative bacterial infection is a serious complication of orthopedic surgery. Not only infections that develop in the first few weeks after surgery but also late infections that develop years after surgery are serious problems. However, the relationship between host bone and infection activation has not yet been explored. Here, we report a novel association between host bone collagen/apatite microstructure and bacterial infection. The bone-mimetic-oriented micro-organized matrix structure was obtained by prolonged controlled cell alignment using a grooved-structured biomedical titanium alloy. Surprisingly, we have discovered that highly aligned osteoblasts have a potent inhibitory effect on Escherichia coli adhesion. Additionally, the oriented collagen/apatite micro-organization of the bone matrix showed excellent antibacterial resistance against Escherichia coli. The proposed mechanism for realizing the antimicrobial activity of the micro-organized bone matrix is by the controlled secretion of the antimicrobial peptides, including β-defensin 2 and β-defensin 3, from the highly aligned osteoblasts. Our findings contribute to the development of anti-infective strategies for orthopedic surgeries. The recovery of the intrinsically ordered bone matrix organization provides superior antibacterial resistance after surgery.
Keywords: Antimicrobial activity; Bone matrix anisotropy; Laser powder bed fusion; Postoperative infection; Surface topography; Titanium alloy.
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