Ng Enoch Ming Wei, Cheong Brandon Huey-Ping, Yu Yang, Liew Oi Wah, Ng Tuck Wah
Laboratory for Optics and Applied Mechanics, Department of Mechanical and Aerospace Engineering, Monash University, Clayton VIC3800, Australia.
Department of Mechanics, Beijing Institute of Technology, Beijing 100081, China.
Rev Sci Instrum. 2016 Nov;87(11):115107. doi: 10.1063/1.4965038.
A method to measure the contact angle, which is indicative of wetting, using small liquid volumes dispensed directly on microplate wells is described and demonstrated. Experiments with enhanced green protein samples of volumes 4.4-6 μl showed no measured variance in the contact angle. Experiments with phosphate buffer solution with varied concentrations of a non-ionic detergent (Tween 20) dissolved, however, revealed smaller contact angles with increased detergent concentration. It is experimentally shown that drops can be located up to 7° from the lowest position of the well without affecting the accuracy of contact angle measurements. Numerical simulations confirm the ability of the drops to manifest the correct contact angle despite the lack of axis-symmetry in their shape while residing on a circular surface. This method offers a convenient means to determine the wetting characteristics of different liquid samples in different microplates.
本文描述并展示了一种使用直接分配在微孔板孔中的少量液体来测量接触角（其指示润湿性）的方法。对体积为4.4 - 6μl的增强型绿色荧光蛋白样品进行的实验表明，接触角测量无变化。然而，对溶解有不同浓度非离子洗涤剂（吐温20）的磷酸盐缓冲溶液进行的实验显示，随着洗涤剂浓度增加，接触角变小。实验表明，液滴可位于孔的最低位置上方达7°，而不影响接触角测量的准确性。数值模拟证实，尽管液滴位于圆形表面时形状缺乏轴对称性，但仍能呈现正确的接触角。该方法为确定不同微孔板中不同液体样品的润湿性提供了一种便捷手段。
