Eco-friendly bacteria-killing by nanorods through mechano-puncture with top selectivity

Jing Ye; Bo Li; Yufeng Zheng; Shuilin Wu; Dafu Chen; Yong Han

doi:10.1016/j.bioactmat.2021.11.028

Eco-friendly bacteria-killing by nanorods through mechano-puncture with top selectivity

Bioact Mater. 2021 Dec 21:15:173-184. doi: 10.1016/j.bioactmat.2021.11.028. eCollection 2022 Sep.

Authors

Jing Ye¹, Bo Li¹, Yufeng Zheng², Shuilin Wu³, Dafu Chen⁴, Yong Han¹

Affiliations

¹ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
² Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.
³ School of Materials Science & Engineering, The Key Laboratory of Advanced Ceramics and Machining Technology by the Ministry of Education of China, Tianjin University, Tianjin, 300072, China.
⁴ Laboratory of Bone Tissue Engineering, Beijing Research Institute of Traumatology and Orthopaedics, Beijing Jishuitan Hospital, Beijing, 100035, China.

Abstract

Nanorods can induce mechano-puncture of Staphylococcus aureus (S. aureus) that often impairs osseointegration of orthopedic implants, while the critical nanorod top sharpness able to puncture S. aureus and the predominant contributor between top sharpness and length to mechano-puncture activity remains elusive. Herein, we fabricated three kinds of Al₂O₃-wrapped nanorods patterned arrays with different lengths and top sharpness. The top-sharp nanorods have lengths of 469 and 884 nm and the shorter show a length identical to the top-flat nanorods. Driven by the equivalent adhesive force of S. aureus, the top-flat nanorods deform cell envelops, showing a bacteriostatic rate of 29% owing to proliferation-inhibited manner. The top-sharp nanorods puncture S. aureus, showing a bactericidal rate of 96% for the longer, and 98% for the shorter that simultaneously exhibits fair osseointegration in bacteria-infected rat tibias, identifying top sharpness as a predominate contributor to mechano-puncture activity. Based on finite-element simulation, such top-flat nanorod derives the maximum stress (S_max) of 5.65 MPa on cell wall, lower than its ultimate-tensile-strength (13 MPa); while such top-sharp and shorter nanorod derives S_max of 20.15 MPa to puncture cell envelop. Moreover, a critical top conical angle of 138° is identified for nanorods able to puncture S. aureus.

Keywords: Anti-bacteria; Finite element simulation; Mechano-puncture; Nanorods; Top sharpness.