Abstract

Background: In recent studies, we have incorporated bile acid and polyelectrolytes into pancreatic β-cell microcapsules and examined their cell viability and microcapsule morphology using various encapsulating methods.

Objective: This study aimed to incorporate 3 colloids; ultrasonic gel (USG; 1%), polystyrenic sulphate (PSS; 0.1%) and polyallylamine (PAA; 3%) and ursodeoxycholic acid (UDCA; 4%) with the polymer sodium alginate (SA; 1.2%) and the copolymer poly-L-ornithine (PLO; 1%), and using a refined vibrational jet-flow microencapsulating method, test the microcapsule properties, and cell viability without or with UDCA.

Method: The pancreatic β-cells NIT-1 were encapsulated using concentric nozzles and a refined method using voltage > 600 mv and frequency of 1750 Hz with syringe flow of 1.5 ml/min (core) and formulation solution of 2.1 ml/min, with a mixture of SA, PLO, USG, PSS and PAA without UDCA (control) or with UDCA (test). Both formulations and microcapsules were examined for surface composition and thermal and chemical biocompatibilities. The microencapsulated cells were examined for bioenergetics and production of inflammatory biomarkers. UDCA distribution within the microcapsules was also examined.

Results: Using our method, viability remained low after the addition of PSS, PAA and USG, while the incorporation of UDCA enhanced cell viability, and thermal stability was maintained.

Conclusion: Our refined microencapsulating method, when incorporating polystyrenic sulphate, polyallylamine, the gel and UDCA at 0.1:3:1:4 ratio respectively, produced stable microcapsules suggesting potential applications in cell microencapsulation and diabetes treatment.

Keywords: Diabetes, artificial cell microencapsulation, NIT-1 cells, bile acid, biomaterials.