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The demand for organ transplantation and repair, coupled with a shortage of available donors, poses an urgent clinical need for the development of innovative treatment strategies for long-term repair and regeneration of injured or diseased tissues and organs. Bioengineering organs, by growing patient-derived cells in biomaterial scaffolds in the presence of pertinent physicochemical signals, provides a promising solution to meet this demand. However, recapitulating the structural and cytoarchitectural complexities of native tissues in vitro remains a significant challenge to be addressed. Through tremendous efforts over the past decade, several innovative biofabrication strategies have been developed to overcome these challenges. This review highlights recent work on emerging three-dimensional bioprinting and textile techniques, compares the advantages and shortcomings of these approaches, outlines the use of common biomaterials and advanced hybrid scaffolds, and describes several design considerations including the structural, physical, biological, and economical parameters that are crucial for the fabrication of functional, complex, engineered tissues. Finally, the applications of these biofabrication strategies in neural, skin, connective, and muscle tissue engineering are explored.

Cardiac tissue engineering has major applications in regenerative medicine, disease modeling and biological studies. Despite the significance, numerous questions still need to be explored to enhance the functionalities of engineered tissue substitutes. In this study, 3D cardiac microtissues are developed through encapsulation of cardiomyocytes and cardiac fibroblasts, as the main cellular constituents of native myocardium. The geometries of the constructs are precisely controlled and assessed for their role on synchronous contraction of the cells. Cardiomyocytes exhibit a native-like phenotype when co-cultured with cardiac fibroblasts as compared to the monoculture condition. Particularly, elongated F-actin fibers with abundance of sarcomeric α-actinin and troponin-I are observed within all layers of the constructs. Higher expressions of connexin-43 and integrin-β1 indicate improved cell-cell and cell-matrix interactions. Amongst co-culture conditions, 2:1 (cardiomyocytes: cardiac fibroblasts) ratio exhibits enhanced functionalities, whereas decreasing the construct size adversely affects the synchronous contraction of the cells. Overall, the study here indicates that the cell-cell ratio and the construct geometry are crucial parameters, which need to be optimized to enhance the functionalities of the engineered tissue substitutes.

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In this study, we developed conductive microgrooved tissue constructs, leading to the formation of highly packed and uniaxially oriented cardiac cytoarchitecture.