Particulate leaching technique

In order to overcome some of the drawbacks associated with the fiber bonding preparation, a solvent-casting and particulate-leaching technique was developed [32], With appropriate thermal treatment porous constructs of synthetic biode-... 

Highly porous membranes with an inter-connected pore structure were produced using this solvent-casting and particulate-leaching technique (Fig. 4a, b). The porosity of porous PLLA membranes could be controlled by varying the amount of salt used to construct the composite material (Fig. 5a). 

The authors described several other fabrication techniques, but their conclusions are the important parts of their report Conventional scaffold fabrication techniques are incapable of precisely controlling pore size, pore geometry, spatial distribution of pores and construction of internal channels within the scaffold. They also state that scaffolds produced by the solvent casting-particulate leaching technique cannot guarantee interconnection of pores because interconnection is dependent on whether the adjacent salt particles are in contact. Moreover, only thin scaffold cross sections can be produced due to difficulty in removing salt particles deep in the matrix. 

Shi et al. have reported the cytotoxicity of SWCNT, ultrashort SWCNTs (US tubes), and functionalized (dodecylated) US tubes (F-US-tube)-reinforced PPF nanocomposites [105]. In this study, porous PPF nanocomposite scaffolds of four different porosities (75, 80, 85, and 90 vol%) were fabricated using a thermal cross-linking particulate-leaching technique. Rat bone marrow stromal cells (BMSCs) were cultured... 

Fig. 7 a The cumulative release of VEGF from PLGA scaffolds fabricated by a gas foaming particulate leaching technique, b The bioactivity of VEGF released from these matrices at days 2, 7, and 14 was comparable to the effect obtained with known doses (5 and 20 ng/mL) of VEGF not incorporated into matrices (determined by an endothelial cell proliferation assay) (J. Control. Release [78], with permission of Elsevier)... 

Rapin, F. and Forstner, U. (1983) Sequential leaching techniques for particulate metal speciation the selectivity of various extractants. In Proceedings of the 4th International Conference on Heavy Metals in the Environment, Vol. 2, Heidelberg, CEP Consultants, Edinburgh, pp. 1074-1077. 

Various techniques, such as intrusion methods, image analysis and weight determinations are used to provide estimates of the porosity and the distribution of pore sizes within a tissue scaffold. This preliminary study of the structural features of particulate-leached PCL scaffolds has shown that reliable measures of porosity can be obtained from simple weighing measurements (Buoyancy method). 

The distribution of pore sizes can be obtained from both mercury porosimetry and capillary flow porometry. These distributions are only representations of the actual scaffold structure reflecting the limitations of the underlying physics behind each technique. For this reason it is very difficult to compare pore size distributions for complex structures, such as particulate-leached tissue scaffolds. 

In addition to the chemical properties of the material, physical properties such as surface area for cell attachment are essential. Various methods of creating pores in these materials to increase sirrface area are used. Scaffolds formed using the different techniques, which include fiber bonding, solvent casting/particulate leaching, gas foaming and phase separation are known, which result in different porosity, pore size, and the promotion of tissue growth [127]. 

Structure relies primarily on the fabrication process. Conventional methods for these pore-strucmred scaffolds include fibre bonding, solvent carting/particulate leaching, gas foaming and phase separation. The porous scaffolds processed using these techniques have controlled pore size and porosity suitable for tissue engineering. 

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