title: Mimicking the quasi-random assembly of protein fibers in the dermis by freeze-drying method.
abstract: Freeze-drying is extensively used for fabrication of porous materials in tissue engineering and biomedical applications, due to its versatility and use of no toxic solvent. However, it has some significant drawbacks. Conventional freeze-drying technique leads to the production of heterogeneous porous structures with side orientated columnar pores. As the top and bottom surfaces of the sample are not in contact with similar environments, different rates of heat transfer in the surfaces and the temperature gradient across the sample establish the preferential direction of heat transfer. To achieve a scaffold with a desirable microstructure for skin tissue engineering, freeze-drying method was modified by controlling the rate of cooling and regulation of heat transfer across the sample during the freezing step. It could create a homogeneous porous structure with more equiaxed non-oriented pores. Freezing the polymeric solution in the aluminum mold enhanced pore interconnectivity relative to the polystyrene mold. Recrystallization process was discussed how to influence the mean pore size of the scaffold when the final freezing temperature varied. Higher final freezing temperature can easily provide the energy required for the recrystallization process, which lead to enlarged ice crystals and resulting pores.
authors: Institute of Polymeric Materials, Sahand University of Technology, Tabriz, Iran; Faculty of Polymer Engineering, Sahand University of Technology, Tabriz, Iran.
authors: Hakimeh
authors: H
authors: Ghaleh
authors: Institute of Polymeric Materials, Sahand University of Technology, Tabriz, Iran; Faculty of Polymer Engineering, Sahand University of Technology, Tabriz, Iran. Electronic address: f.abbasi@sut.ac.ir.
authors: Farhang
authors: F
authors: Abbasi
authors: Institute of Polymeric Materials, Sahand University of Technology, Tabriz, Iran; Faculty of Polymer Engineering, Sahand University of Technology, Tabriz, Iran.
authors: Mina
authors: M
authors: Alizadeh
authors: Stem Cell and Tissue Engineering Research Laboratory, Sahand University of Technology, Tabriz, Iran.
authors: Ali Baradar
authors: AB
authors: Khoshfetrat
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry*; D032701:Biomimetics / Q000379:methods; D003460:Crystallization / Q000379:methods; D020405:Dermis / Q000737:chemistry*; D005612:Freeze Drying / Q000379:methods; D011108:Polymers / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry; D016062:Porosity; D011506:Proteins / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D011137:Polystyrenes; D011506:Proteins; D012996:Solutions
keywords: Freeze-drying; Gelatin; Microstructure; Recrystallization; Skin tissue engineering