Lab-on-a-chip tissue engineered 3D cancer model for in-vitro anti-cancer drug screening

Abstract

Development of in-vitro 3D cellular disease models is emerging at a fast pace. 2D culture systems are limited due to minimal cell-cell interactions and poor stromal intervention. Hence, there is a need to develop 3D models which are more physiologically relevant than 2D models & improves the prediction of drug candidates. 3D models possess more realistic multicellular complexity (cell-cell, cell-matrix interactions) and mimics in-vitro microenvironment more closely. Present study delineates the development of a novel in-vitro 3D cancer model by incorporating cancer aggregates into porous scaffolds. This serves as a portable lab-on-a-chip platform for screening antitumor chemotherapeutic agents. For this purpose, gelatin–chitosan scaffolds were prepared by freeze-drying, crosslinked using glutaraldehyde and investigated for physiochemical and biological characteristics. Microtissue comprising HeLa cells was prepared by Hanging drop technique and embedded into porous scaffolds and cultivated in standard culture conditions. Microtissue viability in the 3D microenvironment of polymeric scaffold was assessed by MTT assay. Cryopreservation performance of microtissue seeded scaffold construct was examined by cooling using liquid N2. Resuscitation of the constructs 2 days of cryopreservation showed that system retained 76% of cell viability and metabolic activity. The constructs were then used as a cancer tissue mimetic to compare the efficacy of two anticancer drugs namely 5-FU and Cisplatin. Not all cells of the microtissue are exposed to the same drug concentration due to poor drug diffusion through the biomimetic scaffold which resembles native ECM. As predicted, percentage cell death is less in case of our model compared to conventional monolayer culture. These results clearly imply that the proposed gelatin-chitosan scaffold based 3D cancer model closely mimics in-vivo tumor conditions and can be used as an in-vitro screening system for anticancer drug screening.