AI 中文总结
研究酶活性对胶体示踪剂扩散的影响，通过结合差分动态显微镜和光镊测量，比较不同配置、不同大小示踪剂的情况，发现酶活性可转换为微观运动和力，增强效果受多种因素影响，对理解非平衡动力学有重要意义。
AI 中文摘要
酶催化可产生非平衡涨落，但其如何在更大长度尺度上与示踪剂运动耦合取决于物理环境。本文研究了两种配置下的胶体示踪剂：分散在酶活性溶液中的被动粒子，以及催化直接发生在示踪剂表面的酶修饰粒子。结合探测系综平均长时间扩散的差分动态显微镜（DDM）和短时间力涨落的光镊（OT）测量，并比较了几种量化活性诱导增强的互补指标。对于1μm的示踪剂，在两种配置中均观察到活性诱导增强，酶修饰粒子效果最强，表现出增强扩散和增加的非热力涨落。对于200nm的示踪剂，增强更微妙且依赖方法：DDM检测到裸粒子扩散有适度增加，而OT未分辨出相应特征。这些结果表明酶活性可从分子尺度转换为微观尺度的运动和力，但增强的表观幅度和可检测性强烈依赖于示踪剂大小、活性定位、测量探测的时间尺度以及用于量化增强的指标。更广泛地说，理解酶活性如何跨尺度改变传输和涨落对于解释活性软物质、细胞内运输和化学拥挤生物环境中的非平衡动力学很重要。
英文摘要
Enzymatic catalysis can generate nonequilibrium fluctuations, but how these couple to tracer motion at larger length scales depends on physical context. Here, we investigate colloidal tracers in two configurations: passive particles dispersed in an enzymatically active solution, and enzyme-decorated particles where catalysis occurs directly at the tracer surface. We combine differential dynamic microscopy (DDM), which probes ensemble-averaged long-time diffusion, with optical tweezer (OT) measurements of short-time force fluctuations, and compare several complementary metrics for quantifying activity-induced enhancement. For 1 $μ$m tracers, we observe activity-induced enhancements in both configurations, with the strongest effects for enzyme-decorated particles, which exhibit enhanced diffusion and increased non-thermal force fluctuations. For 200 nm tracers, enhancements are more subtle and method-dependent: DDM detects modest increases in diffusion for bare particles, while corresponding signatures are not resolved by the OT. These results demonstrate that enzymatic activity can be transduced from molecular to microscale motion and forces, but that the apparent magnitude and detectability of enhancement depend strongly on tracer size, localization of activity, the timescales probed by the measurement, and the metric used to quantify enhancement. More broadly, understanding how enzyme activity modifies transport and fluctuations across scales is important for interpreting nonequilibrium dynamics in active soft matter, intracellular transport, and chemically crowded biological environments.
Comments12 pages, 8 figures
