Suh Junghae, Wirtz Denis, Hanes Justin
Department of Biomedical Engineering, The Johns Hopkins University, 720 Rutland Ave., Baltimore, Maryland 21205, USA.
Biotechnol Prog. 2004 Mar-Apr;20(2):598-602. doi: 10.1021/bp034251y.
We used real-time multiple particle tracking to quantitatively characterize the type and rates of transport of gene nanocarriers within live cells. The heterogeneous cytoplasmic transport of polyethylenimine (PEI)/DNA gene carriers was quantified by tracking their mean-square displacements over time and classified into active and nonactive transport populations on the basis of their effective diffusivities versus time. Nonactive gene carriers frequently displayed hop-diffusion trajectories, suggesting a porous cytoplasmic network of flexible biopolymers or sequential attachment and detachment events. Microtubule-dependent active transport of gene carriers resulted in an effective diffusivity 30-fold greater than that of nonactive carriers (at a time scale of 3 s). Compared to nonactive carriers in control cells with intact microtubules, microtubule depolymerization enhanced short-range motion of gene carriers but resulted in similar long-range transport. Multiple particle tracking characterizes gene carrier transport in complex biological environments and, therefore, may be a useful tool in quantifying rate-limiting steps in gene delivery within cells and other biological media.
我们使用实时多粒子追踪技术来定量表征基因纳米载体在活细胞内的运输类型和速率。通过追踪聚乙烯亚胺（PEI）/DNA基因载体随时间的均方位移，对其异质性细胞质运输进行了量化，并根据其有效扩散系数随时间的变化，将其分为主动运输和非主动运输群体。非主动基因载体经常显示跳跃扩散轨迹，这表明存在由柔性生物聚合物构成的多孔细胞质网络，或者存在连续的附着和脱离事件。基因载体的微管依赖性主动运输导致其有效扩散系数比非主动载体大30倍（在3秒的时间尺度上）。与微管完整的对照细胞中的非主动载体相比，微管解聚增强了基因载体的短程运动，但长程运输相似。多粒子追踪技术可表征复杂生物环境中的基因载体运输，因此，它可能是量化细胞和其他生物介质中基因递送限速步骤的有用工具。
