Order-Disorder Phenomena Laboratory, Department of Physics, Worcester Polytechnic Institute, Worcester, MA 01609, USA.
Department of English, Tezpur University, Tezpur 784028, Assam, India.
Biomolecules. 2021 Feb 5;11(2):231. doi: 10.3390/biom11020231.
The drying of bio-colloidal droplets can be used in many medical and forensic applications. The whole human blood is the most complex bio-colloid system, whereas bovine serum albumin (BSA) is the simplest. This paper focuses on the drying characteristics and the final morphology of these two bio-colloids. The experiments were conducted by varying their initial concentrations, and the solutions were dried under various controlled substrate temperatures using optical and scanning electron microscopy. The droplet parameters (the contact angle, the fluid front, and the first-order image statistics) reveal the drying process's unique features. Interestingly, both BSA and blood drying droplets' contact angle measurements show evidence of a concentration-driven transition as the behavior changes from non-monotonic to monotonic decrease. This result indicates that this transition behavior is not limited to multi-component bio-colloid (blood) only, but may be a phenomenon of a bio-colloidal solution containing a large number of interacting components. The high dilution of blood behaves like the BSA solution. The ring-like deposition, the crack morphology, and the microstructures suggest that the components have enough time to segregate and deposit onto the substrate under ambient conditions. However, there is insufficient time for evaporative-driven segregation to occur at elevated temperatures, as expected.
生物胶体液滴的干燥可应用于许多医学和法医学领域。全血是最复杂的生物胶体体系，而牛血清白蛋白（BSA）是最简单的。本文主要研究这两种生物胶体的干燥特性和最终形态。实验通过改变其初始浓度，并在各种受控的基底温度下使用光学和扫描电子显微镜对溶液进行干燥来进行。液滴参数（接触角、流体前缘和一阶图像统计）揭示了干燥过程的独特特征。有趣的是，BSA 和血液干燥液滴的接触角测量都表明存在浓度驱动的转变，其行为从非单调下降变为单调下降。这一结果表明，这种转变行为不仅限于多组分生物胶体（血液），而可能是含有大量相互作用成分的生物胶体溶液的一种现象。高稀释度的血液表现得像 BSA 溶液一样。环状沉积、裂纹形态和微观结构表明，在环境条件下，各成分有足够的时间进行分离并沉积到基底上。然而，在较高温度下，预计由于蒸发驱动的分离所需的时间不足。
