Quantification of spheroid formation mechanism by size and shape analysis

Abstract

This work aims to describe spheroid formation and growth by examining quantitatively the size distribution and shape of spheroids produced by extrusion-spheronization and rotary processing. Using image analysis, spheroid size was curve fitted to statistical distributions. Spheroid roundness was quantified using aspect ratio, eR, projected sphericity and circularity. These roundness descriptors were correlated with one another and analysed in comparison with simulated spheroid-like shapes. Results showed that spheroid size distribution followed a mixed Gaussian distribution. Image analysis revealed that during early stages of spheronization, spheroids had characteristics of bimodal size distribution and the absence of dumbbell intermediates. When roundness descriptors were correlated with individual spheroids, it could distinguish differences in spheroid shape within a population and during spheronization. Consequently, with spheroids following a mixed Gaussian distribution and the detection of spheroid shape changes, heterogeneity within the spheroid population was revealed and spheroid formation and growth could be quantified more critically.