Piezoelectric Heterogeneity in Collagen Type I Fibrils Quantitatively Characterized by Piezoresponse Force Microscopy
Piezoelectric Heterogeneity in Collagen Type I Fibrils Quantitatively Characterized by Piezoresponse Force Microscopy
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DOI：
10.1021/acsbiomaterials.0c01314
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发表时间：
2020-12-01
影响因子：
5.8
通讯作者：
Cho, Hanna
中科院分区：
文献类型：
--
作者：
Kwon, Jinha;Cho, Hanna
I型胶原的压电性可以提供应力产生的电势，其被认为是解释骨对载荷的适应的候选机制之一。然而，它仍然是具有挑战性的量化压电，因为它的异质性和小幅度。在这项研究中，共振增强piezoresponse力显微镜（PFM）被用来放大一个微弱的piezoresponse的一个单一的胶原纤维与仔细校准的悬臂梁。定量PFM，结合双频共振跟踪方法，成功地确定了各向异性和异质性的胶原纤维中的压电性能。剪切压电系数（d（15））的分布被获得为沿胶原原纤维沿着是周期性的，与重叠区中的值（0.29 pm/V）相比，在差距区中的值（0.51 pm/V）更大。有趣的是，这种压电分布对应于在差距区具有较高刚度的矿化胶原原纤维中机械刚度的周期性分布。考虑到磷灰石晶体在差距区成核，随后沿着胶原纤维生长，压电性能的非均匀性和各向异性的性质突出了胶原压电性在骨矿化中的生理重要性。
Piezoelectricity of Type I collagen can provide the stress-generated potential that is considered to be one of the candidate mechanisms to explain bone's adaptation to loading. However, it is still challenging to quantify piezoelectricity because of its heterogeneity and small magnitude. In this study, resonance-enhanced piezoresponse force microscopy (PFM) was utilized to amplify a weak piezoresponse of a single collagen fibril with a carefully calibrated cantilever. The quantitative PFM, combined with a dual-frequency resonance-tracking method, successfully identified the anisotropic and heterogenous nature of the piezoelectric properties in the collagen fibril. The profile of shear piezoelectric coefficient (d(15)) was obtained to be periodic along the collagen fibril, with a larger value in the gap zone (0.51 pm/V) compared to the value in the overlap zone (0.29 pm/V). Interestingly, this piezoelectric profile corresponds to the periodic profile of mechanical stiffness in a mineralized collagen fibril having a higher stiffness in the gap zone. Considering that apatite crystals are nucleated at the gap zone and subsequently grown along the collagen fibril, the heterogeneous and anisotropic nature of piezoelectric properties highlights the physiological importance of the collagen piezoelectricity in bone mineralization.