Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
J Phys Chem B. 2010 Oct 7;114(39):12632-40. doi: 10.1021/jp1001786.
This work investigated the stability of DSPE-PEG(2000) micelles in the presence of bovine serum albumin (BSA). DSPE-PEG(2000) was found to exist in equilibrium among monomeric, micellar, and BSA-bound states, and this equilibrium shifted toward the BSA-bound state when the temperature increased from 20 to 37 °C. The micellar state is thermodynamically unstable at both temperatures when the concentration of BSA approaches that of DSPE-PEG(2000), and micelle breakup occurs with a first-order time constant of 130 ± 9 min at 20 °C and 7.8 ± 1.6 min at 37 °C. Thus, previous targeting experiments that demonstrate synergistic effects in multiply functionalized DSPE-PEG(2000) micelles are likely due to targeting that occurs on a timescale faster than that of micelle breakup. Micelle breakup was limited by diffusion at 20 °C whereas at 37 °C monomer desorption from the micelle was the rate-limiting step. These findings give clear guidance concerning the lifetimes of micelles that may be used as diagnostic and therapeutic nanoparticles.
本工作研究了二硬脂酰基磷脂酰乙醇胺-聚乙二醇（2000）（DSPE-PEG（2000））胶束在牛血清白蛋白（BSA）存在下的稳定性。DSPE-PEG（2000）在单体、胶束和与 BSA 结合的状态之间存在平衡，当温度从 20°C 升高到 37°C 时，这种平衡向与 BSA 结合的状态移动。当 BSA 的浓度接近 DSPE-PEG（2000）的浓度时，在这两种温度下，胶束状态在热力学上是不稳定的，并且在 20°C 时，胶束破裂的一级时间常数为 130±9min，在 37°C 时为 7.8±1.6min。因此，以前的靶向实验表明，多功能化的 DSPE-PEG（2000）胶束具有协同作用，这很可能是由于靶向作用发生在胶束破裂之前的时间尺度上。在 20°C 时，胶束破裂受到扩散的限制，而在 37°C 时，从胶束中解吸单体是限速步骤。这些发现为可能用作诊断和治疗纳米颗粒的胶束的寿命提供了明确的指导。
