Decellularized extracellular matrix-agarose hybrid bioink development for 3D bioprinting applications

Natural and synthetic biomaterials have been widely used in tissue engineering applications, but these materials lack the functional, mechanical, biological and structural complexity of natural extracellular matrix (ECM). Because reaching such complexity with ECM substitutes is very challenging, using the natural ECM itself as biomaterial in tissue engineering applications has gained much interest. As remnant cellular content from allogenic or xenogenic sources could cause unwanted host response, ECM needs to be decellularized before being used as biomaterial. Conventional tissue engineering approaches do not exhibit the necessary complexity and precision, and hence 3D bioprinting is used to create 3-dimensional structures with desired complexity and precision. Up to now, many biomaterials have been used as bio-inks for 3D bioprinting, but as they lack the necessary complexity, there is a need for novel bioinks. Decellularized extracellular matrix (dECM) is a great candidate to be used as bioink in 3D bioprinting as it provides the necessary microenvironments during and after bioprinting if it can be processed into a printable form. This thesis work aims to create a novel bioink by combining cell sheet derived decellularized extracellular matrix (dECM) with a natural hydrogel, agarose. The cell sheets were decellularized and characterized before used as a bioink. The decellularization protocol and its effects on the structure of the extracellular matrix were evaluated. The dECM was solubilized, neutralized, mixed with 3T3 fibroblast cells and agarose before bioprinting. The blend bioink was bioprinted and cultured for a week. The results showed that the developed decellularization protocols were successful in terms of cellular removal and structural preservation. Also, the hybrid bioink provided an appropriate environment for cellular viability and microenvironment.