The salt was dried for at least 24 hrs and stored at 40 ☌ in a drying oven to remove residual air moisture. Pore size and degree of porosity were individually optimized by varying the particle size and polymer to particle ratio, respectively. Macroporous PDMS scaffolds were fabricated using the solvent casting and particulate leaching technique (SCPL), with sodium chloride (NaCl) crystals as the particulate and poly(dimethylsiloxane) (PDMS) as the solvent. The implications of this platform for tissue engineering applications are discussed. Furthermore, the endotoxin content and in vivo biocompatibility of the scaffold was examined. The ability to modify the hydrophobic surface of the scaffold was evaluated by coating with an adhesion protein and subsequent culture of human mesenchymal stem cells. We demonstrate that macroporous PDMS scaffolds can be fabricated with a large surface to volume ratio and controllable porosity, while maintaining structural integrity and interconnectivity. The advantage of SCPL is that it does not involve hazardous solvents and is straightforward: the degree of porosity can be controlled by varying the percent of particulate to solvent, and the pore size is dictated by the diameter of the porogen. In this study, we fabricated PDMS macroporous scaffolds using the solvent casting and particulate leaching technique (SCPL). The fabrication of macroporous PDMS scaffolds with the desired features of high porosity, strong pore interconnectivity, and larger porosity (> 100 µm) has not, to our knowledge, been explored. Due to these desirable traits, PDMS is a material with a long history in medical implantation with multiple forms generated for various tissue engineering applications. In this manner, the scaffold can be used as a platform for drug delivery, if doped with immunosuppressant compounds or with hydrolytically reactive agents for oxygen delivery. Furthermore, the hydrophobic nature of PDMS permits the encapsulation of compounds for slow release into the scaffold microenvironment. While generally hydrophobic, the PDMS surface can be easily modified, via adsorption of proteins, plasma oxygenation, or conjugation of RGD peptides, to create surfaces that promote cellular adhesion and biorecognition. In addition, given the oxygen demand of cells, the high solubility of oxygen in PDMS renders it an ideal material for cell-based implants. PDMS is an excellent candidate for long term implantation, due to its demonstrated high degree of biocompatibility and biostability following clinical implantation. With this goal in mind, we selected the polymer poly(dimethylsiloxane) (PDMS). Thus, the engineering of macroporous scaffolds with high biocompatibility and biostability could have broad applications. implantable glucose sensors, vascular substitutes, articular cartilage replacements, and islet transplantation. In many tissue engineering applications, biostability and retrievability are highly desirable traits, e.g. Their high degradability, however, might not always be desirable, particularly when their degradation products have the potential to invoke an inflammatory response. PGA and PLGA have been particularly prevalent in the design of macroporous scaffolds, given their ease in fabrication. Synthetic materials, such as poly(ε-caprolactone) (PCL), poly(ethylene glycol) (PEG), and poly(α-hydroxy esters) like poly(glycolic acid) (PGA), poly(lactic acid) (PLA), and poly(lactic- co-glycolic acid) (PLGA), are commonly used for tissue engineering scaffolds. Material selection is tissue-specific and requires a balance of the desired properties of the implant, such as mechanical integrity, pore structure, immunogenicity, biostability, and biorecognition. The selection of an appropriate biocompatible material and fabrication method that meets the above outlined criteria is a complicated task. Ideally, the overall porosity should be at least 90%, with interconnected pores > 100 µm in diameter, e.g. Optimal integration of the scaffold into the host requires constructs to retain a high surface area to volume ratio for: optimal cell-polymer interactions, space for host and transplant remodeling, extracellular matrix (ECM) deposition, intra-device vascularization, reduced host inflammation, and minimal diffusional impedance. Three-dimensional scaffolds for tissue engineering play a critical role in providing a three-dimensional structure and mechanical integrity to the implant, as well supporting cell adhesion, distribution, and proliferation. The field of tissue engineering has great potential to treat and/or cure numerous afflictions, from heart damage to cartilage degradation to organ replacement.
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