The structural origins of bone toughness at the nanoscale are not completely understood.Therefore,we performed in situ scanning using atomic force microscopy during macroscopic mechanical testing of antler and bovine ...The structural origins of bone toughness at the nanoscale are not completely understood.Therefore,we performed in situ scanning using atomic force microscopy during macroscopic mechanical testing of antler and bovine bone,to reveal the origins of the irreversible plastic deformation at the mineralized collagen fibril(MCF)array and MCF levels.We found that the plastic deformation behavior at the nanoscale level could be divided into two stages.The first stage of plastic deformation at the nanoscale level was characterized by slippage between the MCF arrays,which contained mineral aggregate grains with regular shapes under load.In the second stage of nanoscale plastic deformation,the MCFs broke through the bonds of the extrafibrillar mineral aggregate grains and exhibited interfibrillar slippage.These nanoscale plastic deformation behaviors may thus be the origins of stress whitening and irreversible plastic deformation.Thus,the findings in this study not only shed light on the plastic deformation mechanisms of MCF arrays and MCFs,but also provide structural and mechanistic insights into bioinspired materials design and mechanisms of relevant bone diseases.展开更多
基金the National Natural Science Foundation of China(Nos.31500762 and 51672088)the National Key R&D Program of China(Nos.2016YFC1100600 and 2018YFC1106300)+5 种基金the Natural Science Foundation of Guangdong Province,China(No.2014A030310215)Science and Technology Planning Project of Guangdong Province,China(Nos.2019B020230003,2016A010103009,and 2014B010133001)Guangdong Peak Project,China(No.DFJH201802)Science and Technology Program of Guangzhou,China(No.201510010262)the Fundamental Research Funds for the Central Universities(No.2015ZM097)the Excellent Young Talents Plan of Guizhou Medical University(No.2021-101).
文摘The structural origins of bone toughness at the nanoscale are not completely understood.Therefore,we performed in situ scanning using atomic force microscopy during macroscopic mechanical testing of antler and bovine bone,to reveal the origins of the irreversible plastic deformation at the mineralized collagen fibril(MCF)array and MCF levels.We found that the plastic deformation behavior at the nanoscale level could be divided into two stages.The first stage of plastic deformation at the nanoscale level was characterized by slippage between the MCF arrays,which contained mineral aggregate grains with regular shapes under load.In the second stage of nanoscale plastic deformation,the MCFs broke through the bonds of the extrafibrillar mineral aggregate grains and exhibited interfibrillar slippage.These nanoscale plastic deformation behaviors may thus be the origins of stress whitening and irreversible plastic deformation.Thus,the findings in this study not only shed light on the plastic deformation mechanisms of MCF arrays and MCFs,but also provide structural and mechanistic insights into bioinspired materials design and mechanisms of relevant bone diseases.
