Image-Based Analysis of Patterns Formed in Drying Drops

Abstract

Image processing and pattern recognition offer a useful and versatile method for optically characterizing drops of a colloidal solution during the drying process and in its final state. This paper exploits image processing techniques applied to cross-polarizing microscopy to probe birefringence and the bright-field microscopy to examine the morphological patterns. The bio-colloidal solution of interest is a mixture of water, liquid crystal (LC) and three different proteins [lysozyme (Lys), myoglobin (Myo), and bovine serum albumin (BSA)], all at a fixed relative concentration. During the drying process, the LC phase separates and becomes optically active detectable through its birefringence. Further, as the protein concentrates, it forms cracks under strain due to the evaporation of water. The mean intensity profile of the drying process is examined using an automated image processing technique that reveals three unique regimes-a steady upsurge, a speedy rise, and an eventual saturation. The high values of standard deviation show the complexity, the roughness, and inhomogeneity of the image surface. A semi-automated image processing technique is proposed to quantify the distance between the consecutive cracks by converting those into high contrast images. The outcome of the image analysis correlates with the initial state of the mixture, the nature of the proteins, and the mechanical response of the final patterns. The paper reveals new insights on the self-assembly of the macromolecules during the drying mechanism of any aqueous solution. * gsiannac@wpi.edu 1

Temperature and Concentration Dependence of Human Whole Blood and Protein Drying Droplets

“…Finally, it increases to reach saturation. The SD measuring the image texture’s complexity can capture the finer textural details [ 30 , 33 ]. The uniformity of the image after the deposition of the droplet is the highest.…”

“…The crack spacing ( ) is computed by drawing a circular line at each crack domain. The detailed procedure can be found in our previous papers [ 29 , 30 ]. The and are plotted as a function of the initial concentration at each temperature.…”

“…The different observations in the blood and the protein samples are detailed in the next section. The mean is defined as the sum of the pixel values divided by the number of the pixels [30,33]. The mean shows three distinct phases: a rapid rise follows the initial increase, after which a peak appears and, finally, decreases to reach the saturation stage.…”

Concentration-driven phase transition and self-assembly in drying droplets of diluting whole blood

“…To estimate the crack width ( ) and the crack spacing ( ), a circular line was drawn, and their averaged values were also determined at each . The detailed procedure of measurements can be found in 47 .…”

The Effect of Substrate Temperature on the Evaporative Behaviour and Desiccation Patterns of Foetal Bovine Serum Drops

“…Additionally, another work has examined the evaporation of aqueous bio-colloidal solutions containing liquid crystals and different types of proteins: BSA, lysozyme and myoglobin. Image processing techniques were employed in combination with cross-polarised and bright-field microscopy for the examination of the pattern morphology and the quantification of cracks [39].…”