Mineralized polysaccharide capsules as biomimetic microenvironments for cell, gene and growth factor delivery in tissue engineering

This paper presents an overview of our recent studies on mineralized polysaccharide capsules and their potential as multifunctional scaffolds for the organisation and delivery of human cell types, DNA and growth factors. Microcapsules containing these encapsulates are readily produced at room temperature in the form of alginate beads that are stabilized by an outer shell consisting of an ultra thin chitosan-calcium phosphate membrane. Modulation of the shell thickness and composition influences the rates of release and diffusion of encapsulated cells, growth factors and genes to produce microcapsules with tailored spatial and temporal properties that offer significant potential as novel biomimetic delivery systems in tissue engineering applications such as skeletal tissue repair and regeneration. We demonstrate the use of mineralized microcapsules to enable regeneration from encapsulated human mesenchymal populations, functional quantities of growth factor capture, and gene transfection. Significantly, we highlight the ability to fabricate integrated capsules consisting of spatially separated multiple components in nested combination that may provide phased temporal release of appropriate growth factors, analogous to the natural regeneration process.