Biofabrication's Contribution to the Evolution of Cultured Meat

Abstract

Cultured Meat (CM) is a growing field in cellular agriculture, driven by the environmental impact of conventional meat production, which contributes to climate change and occupies ≈70% of arable land. As demand for meat alternatives rises, research in this area expands. CM production relies on tissue engineering techniques, where a limited number of animal cells are cultured in vitro and processed to create meat-like tissue comprising muscle and adipose components. Currently, CM is primarily produced on a small scale in pilot facilities. Producing a large cell mass based on suitable cell sources and bioreactors remains challenging. Advanced manufacturing methods and innovative materials are required to subsequently process this cell mass into CM products on a large scale. Consequently, CM is closely linked with biofabrication, a suite of technologies for precisely arranging cellular aggregates and cell-material composites to construct specific structures, often using robotics. This review provides insights into contemporary biomedical biofabrication technologies, focusing on significant advancements in muscle and adipose tissue biofabrication for CM production. Novel materials for biofabricating CM are also discussed, emphasizing their edibility and incorporation of healthful components. Finally, initial studies on biofabricated CM are examined, addressing current limitations and future challenges for large-scale production.

Keywords: adipose tissue; bioassembly; bioprinting; cultured meat; muscle tissue; scale‐up; tissue engineering.

Figure 1

Biofabrication methods in the production process of CM. The generated cell mass is utilized in the construction of CM products either directly through bioassembly techniques such as cell sheet stacking, the Kenzan method, magnetic levitation, or aspiration‐assisted bioassembly. On the other hand, CM products can also be fabricated by mixing the cell mass with biomaterials using bioprinting methods such as microextrusion, DoD, stereolithography (SLA)/2PP, or digital light processing (DLP). In addition to the biofabrication challenges, considerations must be given to whether the fabrication will take place on‐site or in a factory‐based setting, the design of post‐processing, consumer perceptions of the products and production methods, and the regulatory landscape in this context.

Figure 2

Bioprinting is a versatile tool to engineer advanced muscle‐like constructs. A) Bioprinted constructs have been shown to be advantageous for the maturation of muscle‐like constructs. Compared to non‐printed controls, the cell viability and the expression of muscle biomarkers like MHC are increased in bioprinted constructs. Reproduced with permission.^{[ 69 ]} Copyright 2018, Springer Nature. B) Extrusion‐based bioprinting facilitates the orientation of muscle cells (stained against F‐actin in green) in the printing direction. The alignment of muscle cells is a prerequisite for the formation of myotubes. Reproduced with permission.^{[ 71 ]} Copyright 2016, Wiley‐VCH. C) Bioprinting technologies can be used to fabricate anisotropic structures that are essential for muscle‐like constructs. The arrangement of bioprinted strands along one axis mimics the orientation of muscle fiber bundles. Reproduced with permission.^{[ 75 ]} Copyright 2017, Elsevier.

Figure 3

Bioprinting allows for the fabrication of adipose tissue‐like constructs. A) Bioprinted adipocytes form lobule‐like structures similar to physiological tissue with expression of perilipin A around the lipid vacuole. Reproduced with permission.^{[ 86 ]} Copyright 2022, MDPI. B) ASCs can produce relevant components of the ECM (Collagen IV, Collagen VI) of adipose tissue irrespective of the manufacturing method, evidencing the feasibility of bioprinting to generate adipose tissue. Reproduced with permission.^{[ 88 ]} Copyright 2021, MDPI. C) Bioprinting facilitates the generation of thick, vascularized adipose tissue models. In the presence of bioprinted endothelial cells, a capillary network could be observed after seven days (displayed by staining of CD31 marker) resembling a physiological state. Reproduced with permission.^{[ 90 ]} Copyright 2021, SPJ.

Figure 4

The selection process for biomaterials and additives for the biofabrication of CM. A variety of plant‐based or bacterial source materials exist that can be utilized for the bioprinting of CM. Within these materials, different plant‐based or synthetic additives can be blended to enhance the nutritional value and taste of the products. The cellular mass also encompasses various formats for the different cell types and species. Specific food‐related and process‐oriented requirements apply to both the biomaterials and additives for the bioprinting of CM.

Figure 5

Biofabrication strategies demonstrably suitable for the fabrication of CM. A) Multiple bioprinting technologies have successfully been proven suitable to manufacture meat‐like substitutes. Particularly, microextrusion bioprinting has been mostly studied, but also other technologies, such as DLP bioprinting, are of high relevance. Reproduced with permission.^{[ 26} , ^{124 ]} Copyright 2021 & 2022, Elsevier & Wiley‐VHC. Reproduced with permission.^{[ 122 ]} Copyright 2022, ACS Publications. B) Bioinks can be tailored toward the requirements of CM. For example, the addition of pea protein (PPI) to an alginate‐based bioink led to a positive maturation of a bioprinted construct into CM. Reproduced with permission.^{[ 123 ]} Copyright 2022, Elsevier. C) Biofabricated, meat‐like constructs appear similar to conventional meat regarding shape, color, cooking properties, and bite resistance. Reproduced with permission.^{[ 124} , ^{126 ]} Copyright 2022 & 2021, Wiley‐VHC & Elsevier.