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arXiv 2602.08150physics.optics
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布拉格光谱揭示超声波特性超越水合

Brillouin Spectroscopy Reveals Mechanical Properties Beyond Hydration

Zhe Wang, Maria Regato Herbella, Fereydoon Taheri, Maria de los Angeles De la Cruz Garcia, Gaurav Dave, Christine Selhuber-Unkel

AI总结:

布拉格光谱通过揭示水合和机械特性之间的关系,为生物力学研究提供了新的视角。

摘要:

表征细胞和细胞外基质的微机械特性在机械生物学中至关重要。为满足这一需求,布拉格光散射(BLS)已作为一种非接触、高分辨率的弹性成像工具出现,它探测材料的GHz频率纵向模量。该纵向模量反映了微观尺度上的弹性与粘性行为。然而,在生物样本中解释布拉格光谱具有挑战性:在高度水合样品中,布拉格位移主要由水动力学主导,而GHz纵向模量并不直接等同于传统低频刚度测量(例如杨氏模量或剪切模量)。关于水合和聚合物松弛如何影响布拉格信号,以及如何将其与宏观生物力学联系起来仍存在争论。特别是,通过布拉格散射测量的纵向粘度包括来自体积粘度的贡献,而标准剪切流变学中没有这一贡献,通常被忽视。为了解决这些问题,我们使用了不同的水凝胶系统和溶剂混合物,表明布拉格光谱受到调节但不被水合主导。通过调节明胶浓度,我们证明布拉格位移可以根据其下的机械响应正相关或负相关地与水分含量相关联。对乙醇水混合物的测量进一步澄清了这种行为。尽管布拉格位移强烈依赖于组成,但它不随水分含量单调变化,而是反映了混合物的机械特性变化。通过比较纵向、体积和剪切粘度,我们还展示了体积粘性耗散在布拉格响应中起着重要作用。这些结果建立了一个机械框架,用于解释水合和生物分子系统中的布拉格光谱。

英文摘要:

Brillouin light scattering is a noncontact technique for probing the micromechanical properties of cells and tissues through the GHz-frequency longitudinal modulus. Interpreting Brillouin spectra in hydrated biological materials remains challenging because the Brillouin shift is influenced not only by water content but also by polymer network mechanics, relaxation processes, and viscous dissipation. Here, we investigated two model hydrogels with distinct network chemistry, together with a binary solvent mixture, to disentangle these contributions. Time- and space-resolved measurements of a hydrating hydrogel further show that Brillouin microscopy captures local mechanical changes that bulk rheometry only partially resolves. Experiments on ethanol-water mixtures further demonstrate that the Brillouin shift does not vary monotonically with hydration but instead reflects changes in the mixture's mechanical properties. In addition, by comparing longitudinal, bulk, and shear viscosities, we identify bulk viscous dissipation as an important contributor to the Brillouin response. Together, these results show that hydration modulates Brillouin spectra but does not fully determine them. Our findings provide a mechanical framework for interpreting Brillouin measurements in hydrated and biomolecular systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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