Freeze-Casting of Porous Biomaterials: Structure, Properties and Opportunities

Abstract

The freeze-casting of porous materials has received a great deal of attention during the past few years. This simple process, where a material suspension is simply frozen and then sublimated, provides materials with unique porous architectures, where the porosity is almost a direct replica of the frozen solvent crystals. This review focuses on the recent results on the process and the derived porous structures with regards to the biomaterials applications. Of particular interest is the architecture of the materials and the versatility of the process, which can be readily controlled and applied to biomaterials applications. A careful control of the starting formulation and processing conditions is required to control the integrity of the structure and resulting properties. Further in vitro and in vivo investigations are required to validate the potential of this new class of porous materials.

Estimation of Young’s Modulus of the Porous Titanium Alloy with the Use of Fem Package

“…Porosity also provides proper environment for bone ingrowth in order to achieve a good fixation between porous implant and the surrounding bone. Nowadays, there are a number of manufacturing techniques for the fabrication of porous structures (both for metal and non-metal materials): selective laser melting (SLM) [8,10,14], selective laser sintering (SLS) [11], powder metallurgy (PM) [4], freeze casting [5], space holder [6], sponge replication [7]. These methods are applicable to other biomedical materials like stainless steels, biopolymers or ceramics as well [8,10].…”

Pore structures and mechanical properties of porous titanium scaffolds by bidirectional freeze casting

“…Besides, it is difficult to improve the length of the aligned camphene dendrites, because the freezing rate of camphene is slow and the dendrites do not have enough space to grow up [8]. By contrast, when water was used as the freezing vehicle, highly aligned porous structure throughout the entire sample could be achieved [24,25], and the porous structure can be easily regulated by controlling the freezing conditions [6,26]. In addition, water is more suitable as a solvent than liquid camphene, due to its non-toxicity, ordinary and good biocompatibility [27].…”

“…The 2 increase of porosity is an effective method to reduce the elastic modulus of materials and promotes osteocyte proliferate inside the porous titanium block [5]. The mechanical properties of the materials can be controlled by the porosity, pore size and pore morphology through a variety of manufacturing methods [6]. So far, many manufacturing techniques have been reported to produce porous titanium such as bubble generation [7,8], replication of polymeric sponge [9,10], rapid prototyping method [11,12], space holder method [13,14] and freeze casting [15,16].…”

“…Freeze casting is a promising method to prepare porous materials with unique aligned and elongated pore structure by driving particles of the slurry to self-assemble along the ice growth direction [6,17]. The pore morphologies are mainly determined by matrix powder kinds, solvent types and frozen temperature gradient [18].…”

“…The mechanical properties of the materials can be controlled by the porosity, pore size and pore morphology through a variety of manufacturing methods [6]. So far, many manufacturing techniques have been reported to produce porous titanium such as bubble generation [7,8], replication of polymeric sponge [9,10], rapid prototyping method [11,12], space holder method [13,14] and freeze casting [15,16].Freeze casting is a promising method to prepare porous materials with unique aligned and elongated pore structure by driving particles of the slurry to self-assemble along the ice growth direction [6,17]. The pore morphologies are mainly determined by matrix powder kinds, solvent types and frozen temperature gradient [18].…”