We investigated the ability of surfactant-induced spreading to promote nanoparticle distribution on model mucus hydrogels. The hydrogels were formulated with viscoelastic properties and surface tensions that match those of native lung mucus. Nanoparticle-containing droplets with or without surfactant were deposited on the mucus surface and spreading patterns were monitored by time-course fluorescence imaging. Overall, surfactant-induced spreading of nanoparticles required an appropriate balance between Marangoni forces and viscoelastic subphase resistance. Spreading was enhanced on bare gels by increasing the concentration of surfactant in the droplets or reducing the viscoelastic properties of the subphase. However, with a pre-existing film of pulmonary surfactant on the mucus surface, spreading was dramatically inhibited as the surface tension gradient between the droplets and the surrounding subphase decreased. A complete lack of spreading was observed at surface tensions that matched those in the tracheobronchial region of the lungs, even with full-concentration Infasurf. These studies demonstrate that the magnitude of spreading on lung mucus-like surfaces is limited by native mucosal properties.

中文翻译：

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表面活性剂诱导的纳米颗粒扩散在模拟天然肺部疾病的黏液模拟表面上受到抑制。

我们研究了表面活性剂诱导的扩散以促进模型粘液水凝胶上的纳米颗粒分布的能力。配制的水凝胶具有与天然肺粘液相匹配的粘弹性和表面张力。含或不含表面活性剂的含纳米颗粒的液滴沉积在粘液表面，并通过时程荧光成像监测其扩散方式。总体而言，表面活性剂诱导的纳米颗粒扩散需要在Marangoni力和粘弹性亚相电阻之间保持适当的平衡。通过增加液滴中表面活性剂的浓度或降低子相的粘弹性，可增强裸露凝胶的铺展性。但是，在粘液表面上预先存在肺表面活性剂膜时，随着液滴与周围亚相之间的表面张力梯度降低，扩散得到了显着抑制。即使在全浓度Infasurf的情况下，在与肺气管支气管区域相匹配的表面张力下也观察到完全没有扩散。这些研究表明，在肺粘液样表面上扩散的程度受到天然粘膜特性的限制。