Safi Samghabadi Farshad, Marfai Juexin, Cueva Camyla, Aporvari Mehdi, Neill Philip, Chabi Maede, Robertson-Anderson Rae M, Conrad Jacinta C
Department of Chemical & Biomolecular Engineering, University of Houston, Houston, TX 77204, USA.
Department of Physics and Biophysics, University of San Diego, San Diego, CA 92110, USA.
Soft Matter. 2025 Jan 29;21(5):935-947. doi: 10.1039/d4sm01150c.
Microrheology has become an indispensable tool for measuring the dynamics of macromolecular systems. Yet, its ability to characterize polymer dynamics across spatiotemporal scales, which vary among polymers and concentration regimes, is limited by the selection of probe morphologies and sizes. Here, we introduce semiflexible M13 phage as a powerful microrheological probe able to circumvent these constraints to robustly capture the dynamics of polymeric solutions across decades of concentrations, sizes, and ionic conditions. We show that phage mobility directly couples to the relaxation dynamics of DNA solutions spanning from semidilute to entangled regimes with ionic strengths varying by four orders of magnitude. Phage mobility metrics across a broad range of timescales collapse onto universal master curves that are unexpectedly insensitive to ionic strength and exhibit robust crossovers from semidilute to entangled regime scaling, not captured by current theoretical models. Our results open the door to the use of phage probes to elucidate the complex dynamics of systems exhibiting a spectrum of thermal and active relaxation processes.
微观流变学已成为测量大分子系统动力学的不可或缺的工具。然而，其在跨越时空尺度（这些尺度在聚合物和浓度范围之间有所不同）表征聚合物动力学的能力，受到探针形态和尺寸选择的限制。在此，我们引入半柔性M13噬菌体作为一种强大的微观流变学探针，它能够规避这些限制，从而在几十年的浓度、尺寸和离子条件范围内稳健地捕捉聚合物溶液的动力学。我们表明，噬菌体的迁移率直接与DNA溶液的松弛动力学相关联，该DNA溶液涵盖从半稀溶液到缠结状态，离子强度变化达四个数量级。在广泛的时间尺度上，噬菌体迁移率指标汇聚到通用主曲线上，这些曲线出人意料地对离子强度不敏感，并展现出从半稀溶液到缠结状态标度的稳健转变，这是当前理论模型所未捕捉到的。我们的结果为使用噬菌体探针阐明表现出一系列热弛豫和主动弛豫过程的系统的复杂动力学打开了大门。
