Tissue scaffolds are essential for tissue engineering because they must provide a proper mechanical and chemical environment for seeded cells to grow and operate normally, eventually forming completely functioning tissue. Tissue scaffolds essentially serve two purposes: they give a place for cells to multiply and they have a structure that allows soluble gases, nutrients, and waste products to be transported in a way that satisfies the needs of an expanding cell population. Scaffolds for tissue engineering can also be made from natural materials and are generally biocompatible. For tissue engineering purposes, a variety of materials have been produced as scaffolds. Foaming is used to create scaffolds that most closely fulfill the parameters for an ideal scaffold and most closely mirror the structure of trabecular bone. Biocompatibility is the most important feature of TE scaffolds. Biocompatibility can be defined as a biomaterial's, device's, or system's capacity to fulfil its intended function in relation to a medical therapy without causing any undesired local or systemic consequences in the therapy's recipient or beneficiary. More specifically, a scaffold's biocompatibility for TE applications relates to its capacity to function as a substrate that will support the desired cellular activity.