Ms Aleksandra Siekierska’s Bachelor’s Thesis Defence

30 07 2026

Congratulations to Ms Aleksandra Siekierska, who successfully defended her bachelor’s thesis, entitled ‘Biomechanical properties of outer and inner blastomeres of the 16-cell mouse embryo in the context of developmental plasticity’, on 17 July. The thesis was supervised by Aneta Suwińska, PhD, DSc, University Professor, and reviewed by Marta Polańska, PhD.

Ms Siekierska’s research aimed to compare the biomechanical properties of the outer and inner blastomeres of a 16-cell mouse embryo, determining their potential significance for the plasticity of the pre-implantation embryo. Using fluorescent latex microspheres to label the embryos enabled the two cell populations to be correctly distinguished following isolation. The presence of the apical domain and stability of polarity were assessed using immunofluorescence to detect the ERM protein complex. The biomechanical properties of the blastomeres, namely stiffness and cortical tension, were measured using the micropipette aspiration method. Analysis revealed that outer blastomeres exhibited significantly higher stiffness and cortical tension than inner blastomeres. Furthermore, outer blastomeres analysed in intact embryos were found to be stiffer than cells following isolation, indicating that intercellular contacts significantly influence their biomechanical properties. This suggests that the biomechanical properties of blastomeres do not constitute a cell-autonomous trait, but rather depend on interactions with other cells. The significant differences in biomechanical properties observed between the outer and inner blastomeres suggest that this may be one of the mechanisms involved in regulating the plasticity of the pre-implantation mouse embryo.