Saad Sameh M I, Policova Zdenka, Dang Andrew, Acosta Edgar J, Hair Michael L, Neumann A Wilhelm
Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.
Colloids Surf B Biointerfaces. 2009 Oct 15;73(2):365-75. doi: 10.1016/j.colsurfb.2009.06.013. Epub 2009 Jun 17.
This paper presents a continuation of the development of a drop shape method for film studies, ADSA-CSD (Axisymmetric Drop Shape Analysis-Constrained Sessile Drop). ADSA-CSD has certain advantages over conventional methods. The development presented here allows complete exchange of the subphase of a spread or adsorbed film. This feature allows certain studies relevant to lung surfactant research that cannot be readily performed by other means. The key feature of the design is a second capillary into the bulk of the drop to facilitate addition or removal of a secondary liquid. The development will be illustrated through studies concerning lung surfactant inhibition. After forming a sessile drop of a basic lung surfactant preparation, the bulk phase can be removed and exchanged for one containing different inhibitors. Such studies mimic the leakage of plasma and blood proteins into the alveolar spaces altering the surface activity of lung surfactant in a phenomenon called surfactant inhibition. The resistance of the lung surfactant to specific inhibitors can be readily evaluated using the method. The new method is also useful for surfactant reversal studies, i.e. the ability to restore the normal surface activity of an inhibited lung surfactant film by using special additives. Results show a distinctive difference between the inhibition when an inhibitor is mixed with and when it is injected under a preformed surfactant film. None of the inhibitors studied (serum, albumin, fibrinogen, and cholesterol) were able to penetrate a preexisting film formed by the basic preparation (BLES and protasan), while all of them can alter the surface activity of such preparation when mixed with the preparation. Preliminary results show that reversal of serum inhibition can be easily achieved and evaluated using the modified methodology.
本文介绍了一种用于薄膜研究的液滴形状方法——轴对称液滴形状分析-约束固着液滴法（ADSA-CSD）的后续发展情况。ADSA-CSD相较于传统方法具有一定优势。此处介绍的发展成果使得能够完全更换铺展或吸附薄膜的亚相。这一特性使得一些与肺表面活性剂研究相关的特定研究得以开展，而这些研究用其他方法难以轻易进行。该设计的关键特性是在液滴主体中设置了第二根毛细管，以方便添加或去除第二液体。将通过有关肺表面活性剂抑制的研究来说明这一发展情况。在形成基本肺表面活性剂制剂的固着液滴后，可以去除主体相并更换为含有不同抑制剂的相。此类研究模拟了血浆和血液蛋白质泄漏到肺泡腔中，在一种称为表面活性剂抑制的现象中改变肺表面活性剂的表面活性。使用该方法可以很容易地评估肺表面活性剂对特定抑制剂的抗性。这种新方法对于表面活性剂逆转研究也很有用，即通过使用特殊添加剂恢复受抑制的肺表面活性剂薄膜正常表面活性的能力。结果显示，当抑制剂与预先形成的表面活性剂薄膜混合注入以及单独注入时，抑制情况存在显著差异。所研究的抑制剂（血清、白蛋白、纤维蛋白原和胆固醇）均无法穿透由基本制剂（BLES和protasan）形成的预先存在的薄膜，而当它们与制剂混合时，均能改变该制剂的表面活性。初步结果表明，使用改进后的方法可以轻松实现并评估血清抑制的逆转。
