Particulate-Leaching Techniques

Particulate leaching is one of the popular and easy techniques to fabricate scaffolds with the pore size (~500 pm), percentage porosity (around 94-95%) and desired crystallinity for tissue engineering applications [173, 174]. In short, the salt is first grounded into small particles, and those particles with a desired size are poured into a mold [166, 175]. A polymer solution is then cast into the salt-filled mold. After the evaporation of the solvent, the salt crystals are leached away using water to form the pores of the scaffold. Particulate leaching is a widely used and mature technique in the manufacturing of porous polymer scaffolds, and also has a good performance in the preparation of the reinforced scaffolds, as some research results shown. Guarino et al. [30] prepared the PLLA fibers embedded in a porous PCL matrix by co-use of particulate leaching technique and filament winding technology. Jiao et al. [52] fabricated PLLA-chitosan hybrid scaffolds by particulate-leaching and subsequently freeze-drying, which combined the individual advantages of synthetic and natural polymers. Mou et al. [176] prepared silk fibroin-collagen-HA composite scaffold by particulate leaching method.

The pore size can be controlled by the porogen/polymer ratio and the size of the porogen, such as salt, wax and sugar. The advantage of this method is the requirement of very less amount of polymer to fabricate the scaffold. However, certain critical variables such as pore shape and inter-pore openings are not controlled.

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