Characterization of a novel bile acid-based delivery platform for microencapsulated pancreatic β-cells

Abstract

Introduction

In a recent study, we confirmed good chemical and physical compatibility of microencapsulated pancreatic β-cells using a novel formulation of low viscosity sodium alginate (LVSA), Poly-L-Ornithine (PLO), and the tertiary bile acid, ursodeoxycholic acid (UDCA). This study aimed to investigate the effect of UDCA on the morphology, swelling, stability, and size of these new microcapsules. It also aimed to evaluate cell viability in the microcapsules following UDCA addition.

Materials and methods

Microencapsulation was carried out using a Büchi-based system. Two (LVSA-PLO, control and LVSA-PLO-UDCA, test) pancreatic β-cells microcapsules were prepared at a constant ratio of 10:1:3, respectively. The microcapsules’ morphology, cell viability, swelling characteristics, stability, mechanical strength, Zeta potential, and size analysis were examined. The cell contents in each microcapsule and the microencapsulation efficiency were also examined.

Results

The addition of UDCA did not affect the microcapsules’ morphology, stability, size, or the microencapsulation efficiency. However, UDCA enhanced cell viability in the microcapsules 24 h after microencapsulation (p < 0.01), reduced swelling (p < 0.05), reduced Zeta potential (− 73 ± 2 to − 54 ± 2 mV, p < 0.01), and increased mechanical strength of the microcapsules (p < 0.05) at the end of the 24-h experimental period.

Discussion and conclusion

UDCA increased β-cell viability in the microcapsules without affecting the microcapsules’ size, morphology, or stability. It also increased the microcapsules’ resistance to swelling and optimized their mechanical strength. Our findings suggest potential benefits of the bile acid UDCA in β-cell microencapsulation.

Keywords::

• artificial cell microencapsulation
• bile acids
• cell viability
• diabetes
• islet cells

Acknowledgments

The authors acknowledge the CHIRI at Curtin University and the Curtin-seeding grant for support, and also acknowledge the use of equipment, scientific and technical assistance of the Curtin University Electron Microscope Facility, which has been partially funded by the University, State, and Commonwealth Governments. The authors also acknowledge the Pharmaceutical Technology Laboratory for their valuable assistance (Curtin School of Pharmacy) and the School of Biomedical Science, Curtin University, specifically, Dr Kevin Keane for the training and Professor Philip Newsholme for providing the BRIN BD-11 cells (clonal rat pancreatic β-cells and originally sourced from the European Collection of Cell Cultures (ECACC) and CellBank Australia.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Notice of Correction

The version of this article published online ahead of print on 11th July 2014 contained an error in the Acknowledgements section. The error has been corrected for this version