Polymeric micro‐ and nanoparticles are useful vehicles for delivering cytokines to diseased tissues such as solid tumors. Double emulsion solvent evaporation is one of the most common techniques to formulate cytokines into vehicles made from hydrophobic polymers; however, the liquid–liquid interfaces formed during emulsification can greatly affect the stability and therapeutic performance of encapsulated cytokines. To develop more effective cytokine‐delivery systems, a clear molecular understanding of the interactions between relevant proteins and solvents used in the preparation of such particles is needed. We utilized an integrated computational and experimental approach for studying the governing mechanisms by which interleukin‐12 (IL‐12), a clinically relevant cytokine, is protected from denaturation by albumin, a common stabilizing protein, at an organic‐aqueous solvent interface formed during double emulsification. We investigated protein–protein interactions between human (h)IL‐12 and albumin and simulated these components in pure water, dichloromethane (DCM), and along a water/DCM interface to replicate the solvent regimes formed during double emulsification. We observed that (i) hIL‐12 experiences increased structural deviations near the water/DCM interface, and (ii) hIL‐12 structural deviations are reduced in the presence of albumin. Experimentally, we found that hIL‐12 bioactivity is retained when released from particles in which albumin is added to the aqueous phase in molar excess to hIL‐12 and sufficient time is allowed for albumin‐hIL‐12 binding. Findings from this work have implications in establishing design principles to enhance the stability of cytokines and other unstable proteins in particles formed by double emulsification for improved stability and therapeutic efficacy.

中文翻译：

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阐明载体蛋白在双乳液聚合物纳米粒子内细胞因子稳定中的作用


聚合物微米颗粒和纳米颗粒是将细胞因子传递到实体瘤等患病组织的有用载体。双乳液溶剂蒸发是将细胞因子配制到由疏水性聚合物制成的载体中的最常用技术之一；然而，乳化过程中形成的液-液界面会极大地影响封装细胞因子的稳定性和治疗性能。为了开发更有效的细胞因子递送系统，需要对制备此类颗粒时使用的相关蛋白质和溶剂之间的相互作用有清晰的分子了解。我们利用综合计算和实验方法来研究白蛋白 - 12（IL-12）（一种临床相关细胞因子）在形成的有机-水溶剂界面上免受白蛋白（一种常见的稳定蛋白）变性的控制机制。双重乳化。我们研究了人 (h)IL-12 和白蛋白之间的蛋白质-蛋白质相互作用，并在纯水、二氯甲烷 (DCM) 中模拟这些成分，并沿着水/DCM 界面复制双乳化过程中形成的溶剂状态。我们观察到 (i) hIL-12 在水/DCM 界面附近的结构偏差增加，(ii) hIL-12 结构偏差在白蛋白存在下减少。通过实验，我们发现，当白蛋白以超过 hIL-12 的摩尔量添加到水相中的颗粒中释放时，hIL-12 的生物活性得以保留，并且为白蛋白-hIL-12 结合提供了足够的时间。 这项工作的发现对于建立设计原则具有重要意义，以增强双重乳化形成的颗粒中细胞因子和其他不稳定蛋白质的稳定性，从而提高稳定性和治疗功效。