The tissue engineering of functional tissues depends on the development of suitable scaffolds to support three dimensional cell growth. To improve the properties of the scaffolds, many cell carriers serve dual purposes; in addition to providing cell support, cutting-edge scaffolds biologically interact with adhering and invading cells and effectively guide cellular growth and development by releasing bioactive proteins like growth factors and cytokines. To design controlled release systems for certain applications, it is important to understand the basic principles of protein delivery as well as the stability of each applied biomolecule. To illustrate the enormous progress that has been achieved in the important field of controlled release, some of the recently developed cell carriers with controlled release capacity, including both solid scaffolds and hydrogel-derived scaffolds, are described and possible solutions for unresolved issues are illustrated.