Supplementary Information files for "Characterisation of particle-surface interactions via anharmonic acoustic transduction"

These are the SI files for the article "Characterisation of particle-surface interactions via anharmonic acoustic transduction".<br>Abstract:Most transduction methods for measuring particle-surface interactions are unable to differentiate the strength of interaction and largely reliant on extensive washing to reduce the ubiquitous non-specific background. Label-based methods, in particular, are limited in wide applicability due to their inherent operational complexity. On the other hand, label-free force-spectroscopic methods that can differentiate particle-surface interaction strength are skill-demanding and time-consuming. Here, we present a label-free anharmonic (nonlinear) acoustic transduction method employing the quartz crystal resonator that reads out ligand-receptor binding based on the interaction strength. We show that while stronger specific interactions are transduced more strongly, and in linear proportionality to the ligand concentration on microparticles, non-specific interactions are significantly attenuated. This allows ligand quantification with high specificity and sensitivity in realtime under flow without separate washing steps. Constructing an analytical model of a quartz resonator, we can relate the number and type (specific vs. non-specific) of ligand-receptor interactions with the change in characteristic nonlinearity coefficient of the resonator. The entirely-electronic and microfluidic-integrable transduction method could potentially allow a simple, fast and reliable way for characterising particle-surface interactions with economy of scale.

这些是论文《通过非简谐声学转导表征颗粒-表面相互作用》的补充信息（SI）文件。<br>摘要：大多数用于测量颗粒-表面相互作用的转导方法无法区分相互作用强度，且在很大程度上依赖大量洗涤以降低普遍存在的非特异性背景。特别是基于标记的方法，因其固有的操作复杂性而限制了广泛应用。另一方面，能够区分颗粒-表面相互作用强度的无标记力谱方法（label-free force-spectroscopic methods）对技术要求高且耗时。本文提出一种基于石英晶体谐振器（quartz crystal resonator）的无标记非简谐（非线性）声学转导方法，该方法可根据相互作用强度读取配体-受体结合情况。我们发现，更强的特异性相互作用的转导信号更强，且与微颗粒上的配体浓度呈线性比例关系，而非特异性相互作用则显著减弱。这使得在流动条件下无需单独洗涤步骤即可实时、高特异性和高灵敏度地定量配体。通过构建石英晶体谐振器的分析模型，我们可将配体-受体相互作用的数量和类型（特异性 vs 非特异性）与谐振器特征非线性系数的变化关联起来。这种全电子且可集成微流控的转导方法有望为颗粒-表面相互作用表征提供一种简单、快速、可靠且具有规模经济性的途径。