Evaluation of microcarriers as a 3D platform for differentiation of iPSC into pancreatic islet-like clusters

Abstract

Scalable production of stem cell-derived β-like cells is essential for advancing iPSC-based therapies for type 1 diabetes. Microcarriers offer a promising strategy for bioprocess intensification due to their high surface-to-volume ratio and compatibility with suspension bioreactors. This study evaluated whether microcarriers can support the direct differentiation of induced pluripotent stem cells (iPSC) into β-like cells under dynamic conditions. iPSC were cultured on Cytodex-1 microcarriers in spinner flasks and differentiated using two protocols: Hogrebe et al. and Velazco-Cruz et al. Differentiation efficiency and marker expression were assessed via flow cytometry and immunohistochemistry. Due to poor differentiation outcomes, an alternative approach was tested: iPSC were first differentiated into pancreatic progenitor cells (PPCs) in 2D, enriched for GP2⁺ cells via MACS, and then expanded on microcarriers. Neither protocol induced β-cell maturation on microcarriers, as shown by poor cell adhesion and absence of key markers. However, microcarriers supported robust expansion of GP2⁺ PPCs, with higher proliferation rates and preservation of PDX1⁺ and NKX6.1⁺ profiles compared to 2D culture. This expansion stage provides a critical intermediate for scalable α and β-like cell production, facilitating large-scale PPC generation for subsequent aggregation and terminal differentiation—though this was not tested in this study. This strategy offers a scalable upstream solution for producing high-quality precursor cells for islet-like cluster formation in future therapeutic applications.