## 1 Introduction  
Tissue engineering (TE) scaffolds temporarily provide the cells with a three-dimensional (3D) structure until the cells produce their own extracellular matrix (ECM) to replace the scaffold. Scaffolds should sustain cell growth and collagen production and provide guidance to the newly developed tissue [1]. Ideally, scaffolds should also mimic the native 3D ECM structure to guide cell growth in a specific direction and be produced in a reproducible and inexpensive manner. The scaffold microstructure is characterised by its porosity, pore size, pore shape, interconnectivity and orientation. Each of these parameters influences the physical properties (e.g., mechanical properties and degradation rate) and biological properties (e.g., cell proliferation, cell differentiation, collagen production and angiogenesis), and ultimately control the growth of the new tissue [2]. One of the main factors that influence the scaffold microstructure is the scaffold fabrication method, such as freeze drying, electrospinning or porogen leaching. Freeze drying is a fabrication technique that involves dissolving or suspending a material in a solvent, which is then frozen and sublimed, leaving a porous scaffold with a microstructure mirroring the ice crystals that formed during the freezing of the solution [3]. Therefore, by controlling the ice crystal growth during the freezing of the solution, the microstructure of the scaffold can be designed and manufactured to mimic the ECM of native tissues, a process called ice-templating (also known as modified thermal induced phase separation). The focus of this study was to utilise ice-templating based on freeze drying and custom-made moulds, in combination with airbrushing to fabricate polymer scaffolds mimicking the microstructure of soft tissues such as skin, oral mucosa and tendon. Furthermore, it is also important to use a biomaterial that is capable of showing tuneable physical properties in order to match its properties as close as possible to the target tissue. A promising material to be used as a soft tissue engineering scaffold is a biocompatible and biodegradable elastomer, poly(glycerol sebacate urethane) (PGSU). [PERSON] et al. [4] showed that PGSU had tuneable mechanical properties and degradation rates by altering the molar ratio of the reactants, as well as excellent biological properties in vitro. They then proceeded to subcutaneously implant PGSU films in rat animal models for a 40-week period, examining the acute and chronic inflammatory response. No adverse reaction or any other complications were found over the 40-week period, and, at some time-points, the PGSU had less foreign body response compared to poly(lactic-co-glycolic acid) (PLGA), which is a Food and Drug Administration (FDA)-approved material for internal use. [PERSON] et al. [5] used freeze drying to produce PGSU scaffolds and found that by reducing the ratio of glycerol:hexamethylene diisocyanate (HDI), the degradation rate of the scaffolds became slower, and the mechanical properties changed. Subsequently, a study by [PERSON] et al. [6] examined the control of the microstructure of PGSU scaffolds by altering the concentration of the PGSU pre-polymer in the freezing solution during fabrication. It was found that by increasing the pre-polymer concentration, the pore size became smaller, degradation rate was reduced and mechanical properties were enhanced. It was also demonstrated that the metabolic activity of fibroblast cells was not affected by the pore size, but the collagen production, angiogenesis and tissue ingrowth were significantly better for the PGSU scaffolds that had pore sizes around 28.2 \(\upmu\)m when compared to the other scaffolds investigated [6]. To mimic the architecture of soft tissues, it is necessary to understand their microstructure and function. Skin tissue functions as a protective barrier to separate the underlying tissue from the environment.