Numerical simulations to determine the influence of mould design on ice-templated scaffold structures

Abstract

In recent years, there has been a shift from traditional cell culture on two-dimensional substrates towards the use of three-dimensional scaffolds for tissue engineering. Ice-templating is a versatile tool to create porous scaffolds from collagen. Here we discuss specific considerations for the design of moulds to produce freeze dried collagen scaffolds with pore sizes of around 100µm, a range that is relevant to tissue engineering. A numerical model of heat conduction, implemented in COMSOL Multiphysics® version 5.0, calculated the temperature contour lines and heat flow vectors during cooling for a variety of mould geometries and materials. We show how temperature distribution within moulds determines the resulting pore structure of the scaffolds by regulating ice growth, and we validate our simulation against experimental results. These simulations are especially useful when working with moulds that contain volumes of more than 1cm in each direction.

Freeze casting – A review of processing, microstructure and properties via the open data repository, FreezeCasting.net

“…fluid type [146], additives [147], particle fraction [148]) as well as solidification conditions (e.g. solidification technique [149], cold plate temperature [150], mold design [151,152] and substrate material [153]). However, this freedom also adds significant complexity when attempting to understand the underlying principles that govern the microstructure templated during the process.…”

Recent advances in ice templating: from biomimetic composites to cell culture scaffolds and tissue engineering

“…This aspect is particularly relevant to shape heatlabile proteins prone to denaturation such as collagen whose importance in cell culture is paramount. 13,96,97 Another interesting aspect that is inherent to ice templating is the ability to reveal the porosity of the material without the use of leaching agents such as a second solvent. Different levers can be used to tune the suitability of a macroporous material to 3D cell culture, as discussed elsewhere.…”

Targeted protein delivery: carbodiimide crosslinking influences protein release from microparticles incorporated within collagen scaffolds

“…By controlling the ice nucleation and growth, one can achieve tuneable architectural structures with defined pore sizes and transport pathways [10, 20, 21]. Scaffold architecture can be affected by the mould design, which can influence the nucleation and growth of ice [22]. The mechanical properties and stability of the 3D ice-templated collagen scaffolds are important for cell-biomaterial interaction and, while dependent on the scaffold composition, are routinely controlled by applying crosslinking processes to the scaffold [18, 19, 23].…”