Statistical Image Analysis of Drying Bovine Serum Albumin Droplets in Phosphate Buffered Saline

TL;DR

This study analyzes the morphological patterns of drying bovine serum albumin droplets in phosphate-buffered saline using statistical image analysis techniques, revealing structural changes and phase separation phenomena relevant for bio-colloidal diagnostics.

Contribution

It introduces the use of first-order statistics and GLCM analysis to characterize structural changes in protein droplets, linking morphology to initial solution conditions.

Findings

GLCM captures structural relationships in droplet images.

Distinct bimodal distributions indicate phase separation.

Local equilibrium regions emerge in steady-state droplets.

Abstract

A bio-colloidal drying droplet can be used as a pre-diagnostic technique. However, a successful clinical setting requires a fundamental understanding of the final morphology and the way it is related to the initial state of the constituents present in the droplet. This chapter focuses on the physics associated with different pattern formations in the globular protein, bovine serum albumin (BSA) at different phosphate-buffered saline concentrations. The study reports that the first-order statistics (FOS) and the gray level co-occurrence matrix (GLCM) analysis are capable of capturing structural changes of the droplets. While the FOS of the image depends on the individual pixels, the GLCM summarizes both tonal and structural relationships between the neighboring pixels. The horizontal and the vertical orientations of the GLCM parameters show a non-significant effect when the pixel displacement is $\leq$ 1. Interestingly, two local equilibrium-like regions (the rim and the central regions) appear when these droplets approach the steady-state. The bimodal distribution confirms that the BSA-BSA interactions are dominant (recessive) over the BSA-saline interactions in the rim (central) regions that result in the phase-separated aggregation of the BSA particles in the presence of the salts.