Piezoelectricity in bone is thought to be a mechanism by which ultrasound promotes the healing of bone fractures. However, a few studies have been conducted in the more clinically relevant megahertz range. To understand the piezoelectricity in bone, we fabricated ultrasound transducers using bone samples as piezoelectric materials and identified the longitudinal ultrasound radiation and reception in the megahertz range. The maximum transmitting sensitivity of the bone transducer was 140 mPa/V, which was nearly 1/1000 of a polyvinylidene difluoride (PVDF) transducer that has better electrical properties and piezoelectricity. The resonance frequencies of the transducer depend on the plate thickness and angle between the bone axis (alignment direction of the hydroxyapatite crystallites) and ultrasound propagation direction, reflecting the anisotropic character of the bone. The reception and transmission sensitivities of the bone transducers also depend on the plate thickness and angle, showing maximum values at off-axis angles. These results indicate the existence of both piezoelectricity and inverse piezoelectricity in bone, which may be key factors in understanding the bone healing by low-intensity biophysical (electrical or mechanical) stimulation.

中文翻译：

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兆赫兹范围内的骨组织板的压电和反压电响应。

骨骼中的压电被认为是超声波促进骨折愈合的一种机制。但是，已经在临床上相关的兆赫兹范围内进行了一些研究。为了了解骨骼中的压电性，我们使用骨骼样本作为压电材料制造了超声换能器，并确定了兆赫兹范围内的纵向超声辐射和接收。骨传感器的最大发射灵敏度为140 mPa / V，约为电性能和压电性更好的聚偏二氟乙烯（PVDF）传感器的1/1000。换能器的共振频率取决于板的厚度以及骨轴（羟基磷灰石微晶的排列方向）与超声传播方向之间的夹角，反映出骨骼的各向异性。骨换能器的接收和传输灵敏度也取决于板的厚度和角度，在离轴角处显示最大值。这些结果表明骨骼中同时存在压电性和逆压电性，这可能是理解低强度生物物理（电或机械）刺激对骨骼愈合的关键因素。