Harvesting decellularized liver extracellular matrix from rodents for 3D scaffold fabrication.

Decellularization is a process to harvest the decellularized extra cellular matrix (dECM) that helps develop 3D scaffolds which mimic the native tissue composition. The decellularized tissues retain the structural and functional properties of the extracellular matrix (ECM) by an efficient decellularization process that retains tissue-specific biochemical and biophysical cues for tissue regeneration. In this study, we report an injection-based decellularization method, without perfusion setup. This study also compares the efficiency of the proposed protocol in the two animal models viz rat and mice. This method harvests rat and mice liver dECM using ethylenediamine tetra acetic acid (EDTA) and sodium dodecyl sulphate (SDS) within 08 h and 02 h respectively and preserved significant amount of ECM proteins. We reported that the harvested mice decellularized extracellular matrix (mdECM) and rat decellularized extracellular matrix (rdECM) had significant reduction in their DNA content (∼97%) and retained structural architecture resembling their native tissue counterparts. The total protein content retained in mdECM was ∼39% while that retained in rdECM was ∼65%. It was also found that the sGAG (sulphated glycosaminoglycan) content showed a no List of Figures.

Decellularization and Their Significance for Tissue Regeneration in the Era of 3D Bioprinting.

Three-dimensional bioprinting is an emerging technology that has high potential application in tissue engineering and regenerative medicine. Increasing advancement and improvement in the decellularization process have led to an increase in the demand for using a decellularized extracellular matrix (dECM) to fabricate tissue engineered products. Decellularization is the process of retaining the extracellular matrix (ECM) while the cellular components are completely removed to harvest the ECM for the regeneration of various tissues and across different sources. Post decellularization of tissues and organs, they act as natural biomaterials to provide the biochemical and structural support to establish cell communication. Selection of an effective method for decellularization is crucial, and various factors like tissue density, geometric organization, and ECM composition affect the regenerative potential which has an impact on the end product. The dECM is a versatile material which is added as an important ingredient to formulate the bioink component for constructing tissue and organs for various significant studies. Bioink consisting of dECM from various sources is used to generate tissue-specific bioink that is unique and to mimic different biometric microenvironments. At present, there are many different techniques applied for decellularization, and the process is not standardized and regulated due to broad application. This review aims to provide an overview of different decellularization procedures, and we also emphasize the different dECM-derived bioinks present in the current global market and the major clinical outcomes. We have also highlighted an overview of benefits and limitations of different decellularization methods and various characteristic validations of decellularization and dECM-derived bioinks.

Three Dimensional Bioprinting for Hepatic Tissue Engineering: From In Vitro Models to Clinical Applications.

Fabrication of functional organs is the holy grail of tissue engineering and the possibilities of repairing a partial or complete liver to treat chronic liver disorders are discussed in this review. Liver is the largest gland in the human body and plays a responsible role in majority of metabolic function and processes. Chronic liver disease is one of the leading causes of death globally and the current treatment strategy of organ transplantation holds its own demerits. Hence there is a need to develop an in vitro liver model that mimics the native microenvironment. The developed model should be a reliable to understand the pathogenesis, screen drugs and assist to repair and replace the damaged liver. The three-dimensional bioprinting is a promising technology that recreates in vivo alike in vitro model for transplantation, which is the goal of tissue engineers. The technology has great potential due to its precise control and its ability to homogeneously distribute cells on all layers in a complex structure. This review gives an overview of liver tissue engineering with a special focus on 3D bioprinting and bioinks for liver disease modelling and drug screening.