Colloidal particles with specific binding affinity are essential for in vivo and in vitro biosensing, targeted drug delivery, and micrometer-scale self-assembly. Key to these techniques are surface functionalizations that provide high affinities to specific target molecules. For stabilization in physiological environments, current particle coating methods rely on adsorbed surfactants. However, spontaneous desorption of these surfactants typically has an undesirable influence on lipid membranes. To address this issue and create particles for targeting molecules in lipid membranes, we present here a surfactant-free coating method that combines high binding affinity with stability at physiological conditions. After activating charge-stabilized polystyrene microparticles with EDC/Sulfo-NHS, we first coat the particles with a specific protein and subsequently covalently attach a dense layer of poly(ethyelene) glycol. This polymer layer provides colloidal stability at physiological conditions as well as antiadhesive properties, while the protein coating provides the specific affinity to the targeted molecule. We show that NeutrAvidin-functionalized particles bind specifically to biotinylated membranes and that Concanavalin A-functionalized particles bind specifically to the glycocortex of Dictyostelium discoideum cells. The affinity of the particles changes with protein density, which can be tuned during the coating procedure. The generic and surfactant-free coating method reported here transfers the high affinity and specificity of a protein onto colloidal polystyrene microparticles.

中文翻译：

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具有特定结合亲和力的无表面活性剂的胶体颗粒

具有特异性结合亲和力的胶体颗粒对于体内和体外生物传感，靶向药物递送以及微米级自组装至关重要。这些技术的关键是表面官能化，可对特定目标分子提供高亲和力。为了在生理环境中稳定，当前的颗粒包衣方法依赖于吸附的表面活性剂。然而，这些表面活性剂的自发解吸通常对脂质膜具有不希望的影响。为了解决这个问题并创建用于靶向脂质膜分子的颗粒，我们在这里提出了一种无表面活性剂的包衣方法，该方法结合了高结合亲和力和在生理条件下的稳定性。用EDC /磺基-NHS活化电荷稳定的聚苯乙烯微粒后，我们首先在颗粒上涂上特定的蛋白质，然后共价附着一层致密的聚乙二醇。该聚合物层在生理条件下提供了胶体稳定性以及抗粘附特性，而蛋白质涂层则提供了与目标分子的特异性亲和力。我们显示，NeutrAvidin功能化的颗粒特异性结合到生物素化膜上，而伴刀豆球蛋白A功能化的颗粒特异性结合到糖皮质激素上。盘基网柄菌细胞。颗粒的亲和力随蛋白质密度而变化，可以在包被过程中进行调节。本文报道的无表面活性剂的通用涂层方法将蛋白质的高亲和力和特异性转移到胶体聚苯乙烯微粒上。