Correlating network structure with functional properties of capillary alginate gels for muscle fiber formation

A review on the characterization of edible scaffolds for cultured meat: Physical, chemical, biocompatibility, and food safety evaluation methods

Scaffolds are three-dimensional biomaterials that act as structural blueprint for cultured meat precursor cells. The advancement of scaffold fabrication techniques and the development of novel scaffolds specifically designed for cultured meat are evident in numerous scaffold-based cultured meat reports, highlighting the advantages of the scaffolds using different characterization and evaluation techniques encompassing the physical, mechanical, chemical, and biological features of the scaffolds. Considering the potential of scaffolds to be included in cultured meat products, standardization of evaluation techniques could aid in preventing misrepresentation and possible food safety concerns in cultured meat production. Thus, appropriate food safety evaluation methods must be included to properly establish scaffolds as food safe or edible. The standardization of scaffold evaluation methods could aid in increasing the dependability and consumption of scaffold-based cultured meat.

Development of a serum-free medium for myoblasts long-term expansion and 3D culture for cell-based meat

Cell-based meat technology provides an effective method to meet the demand for meat, while also posing a huge challenge to the expansion of myoblasts. It is difficult to develop serum-free medium suitable for long-term culture and large-scale expansion of myoblasts, which causes limited understanding of myoblasts expansion. Therefore, this study used C2C12 myoblasts as model cells and developed a serum-free medium for large-scale expansion of myoblasts in vitro using the Plackett-Burman design. The serum-free medium can support short-term proliferation and long-term passage of C2C12 myoblasts, while maintaining myogenic differentiation potential well, which is comparable to those of growth medium containing 10% fetal bovine serum. Based on the C2C12 myoblasts microcarriers serum-free culture system established in this study, the actual expansion folds of myoblasts can reach 43.55 folds after 7 days. Moreover, cell-based meat chunks were preliminarily prepared using glutamine transaminase and edible pigments. The research results provide reference for serum-free culture and large-scale expansion of myoblasts in vitro, laying the foundation for cell-based meat production. PRACTICAL APPLICATION: This study developed a serum-free medium suitable for long-term passage of myoblasts and established a microcarrier serum-free culture system for myoblasts, which is expected to solve the problem of serum-free culture and large-scale expansion of myoblasts in cell culture meat production.

Tea polyphenols coated sodium alginate-gelatin 3D edible scaffold for cultured meat

This study aimed to use edible scaffolds as a platform for animal stem cell expansion, thus constructing block-shaped cell culture meat. The tea polyphenols (TP)-coated 3D scaffolds were constructed of sodium alginate (SA) and gelatin (Gel) with good biocompatibility and mechanical support. Initially, the physicochemical properties and mechanical properties of SA-Gel-TP scaffolds were measured, and the biocompatibility of the scaffolds was evaluated by C2C12 cells. SEM results showed that the scaffold had a porous laminar structure with TP particles attached to the surface, while FT-IR results also demonstrated the encapsulation of TP coating on the scaffold. In addition, the porosity of all scaffolds was higher than 40% and the degradation rate during the incubation cycle was less than 40% and the S2-G1-TP0.1-3 h scaffold has excellent cell adhesion and extension. Subsequently, we inoculated rabbit skeletal muscle myoblasts (RbSkMC) on the scaffold and induced differentiation. The results showed good adhesion and extension behavior of RbSkMC on S2-G1-TP0.1-3 h scaffolds with high expression of myogenic differentiation proteins and genes, and SEM results confirmed the formation of myotubes. Additionally, the adhesion rate of cells on scaffolds with TP coating was 1.5 times higher than that on scaffolds without coating, which significantly improved the cell proliferation rate and the morphology of cells with extension on the scaffolds. Furthermore, rabbit-derived cultured meat had similar appearance and textural characteristics to fresh meat. These conclusions indicate the high potential of the scaffolds with TP coating as a platform for the production of cultured meat products.

Relationship between Rate-Limiting Process and Scaling Law in Gel Growth Induced by Liquid-Liquid Contact

Gelation through the liquid-liquid contact between a polymer solution and a gelator solution has been attempted with various combinations of gelator and polymer solutions. In many combinations, the gel growth dynamics is expressed as X∼t, where X is the gel thickness and t is the elapsed time, and the scaling law holds for the relationship between X and t. In the blood plasma gelation, however, the crossover of the growth behavior from X∼t in the early stage to X∼t in the late stage was observed. It was found that the crossover behavior is caused by a change in the rate-limiting process of growth from the free-energy-limited process to the diffusion-limited process. How, then, would the crossover phenomenon be described in terms of the scaling law? We found that the scaling law does not hold in the early stage owing to the characteristic length attributable to the free energy difference between the sol-gel phases, but it does in the late stage. We also discussed the analysis method for the crossover in terms of the scaling law.

Edible films for cultivated meat production

Biomaterial scaffolds are critical components in cultivated meat production for enabling cell adhesion, proliferation, differentiation and orientation. Currently, there is limited information on the fabrication of edible/biodegradable scaffolds for cultivated meat applications. In the present work, several abundant, naturally derived biomaterials (gelatin, soy, glutenin, zein, cellulose, alginate, konjac, chitosan) were fabricated into films without toxic cross-linking or stabilizing agents. These films were investigated for support of the adhesion, proliferation and differentiation of murine and bovine myoblasts. These biomaterials supported cell viability, and the protein-based films showed better cell adhesion than the polysaccharide-based films. Surface patterns induced cell alignment and guided myoblast differentiation and organization on the glutenin and zein films. The mechanical properties of the protein films were also assessed and suggested that a range of properties can be achieved to meet food-related goals. Overall, based on adherence, proliferation, differentiation, mechanics, and material availability, protein-based films, particularly glutenin and zein, showed the most promise for cultivated meat applications. Ultimately, this work presents a comparison of suitable biomaterials for cultivated meat applications and suggests future efforts to optimize scaffolds for efficacy and cost.

Consumer Acceptance and Production of In Vitro Meat: A Review

In vitro meat (IVM) is a recent development in the production of sustainable food. The consumer perception of IVM has a strong impact on the commercial success of IVM. Hence this review examines existing studies related to consumer concerns, acceptance and uncertainty of IVM. This will help create better marketing strategies for IVM-producing companies in the future. In addition, IVM production is described in terms of the types of cells and culture conditions employed. The applications of self-organising, scaffolding, and 3D printing techniques to produce IVM are also discussed. As the conditions for IVM production are controlled and can be manipulated, it will be feasible to produce a chemically safe and disease-free meat with improved consumer acceptance on a sustainable basis.

Impact of Glucose on the Nanostructure and Mechanical Properties of Calcium-Alginate Hydrogels

Alginate is a polysaccharide obtained from brown seaweed that is widely used in food, pharmaceutical, and biotechnological applications due to its versatility as a viscosifier and gelling agent. Here, we investigated the influence of the addition of glucose on the structure and mechanical properties of alginate solutions and calcium-alginate hydrogels produced by internal gelation through crosslinking with Ca²⁺. Using ¹H low-field nuclear magnetic resonance (NMR) and small angle neutron scattering (SANS), we showed that alginate solutions at 1 wt % present structural heterogeneities at local scale whose size increases with glucose concentration (15–45 wt %). Remarkably, the molecular conformation of alginate in the gels obtained from internal gelation by Ca²⁺ crosslinking is similar to that found in solution. The mechanical properties of the gels evidence an increase in gel strength and elasticity upon the addition of glucose. The fitting of mechanical properties to a poroelastic model shows that structural changes within solutions prior to gelation and the increase in solvent viscosity contribute to the gel strength. The nanostructure of the gels (at local scale, i.e., up to few hundreds of Å) remains unaltered by the presence of glucose up to 30 wt %. At 45 wt %, the permeability obtained by the poroelastic model decreases, and the Young’s modulus increases. We suggest that macro (rather than micro) structural changes lead to this behavior due to the creation of a network of denser zones of chains at 45 wt % glucose. Our study paves the way for the design of calcium-alginate hydrogels with controlled structure for food and pharmaceutical applications in which interactions with glucose are of relevance.

Panorama and ambiguities of cultured meat: an integrative approach

The purpose of this research was to identify, through a systematic review of the literature, the strengths, weaknesses, threats and opportunities of the production and commercialization of cultured meat, as well as to analyze the challenges to be faced by this new food biotechnology. For this, we analyzed 194 manuscripts published in the Scopus and Web of Science databases that dealt with cultured meat under the perspective of cellular agriculture, employing several nomenclatures. The results indicate that there is still no consensus in the literature about the strengths, weaknesses, threats and opportunities of cultured meat, which constitutes an emerging, multifaceted, and encouraging field of study, and a series of inferences have been made that provide insights into the knowledge analyzed. Finally, we propose an analytical model that combines sub-scenarios from which it becomes possible to understand and anticipate the direction of this new food biotechnology.

A New Edible Film to Produce In Vitro Meat

In vitro meat is a novel concept of food science and biotechnology. Methods to produce in vitro meat employ muscle cells cultivated on a scaffold in a serum-free medium using a bioreactor. The microstructure of the scaffold is a key factor, because muscle cells must be oriented to generate parallel alignments of fibers. This work aimed to develop a new scaffold (microstructured film) to grow muscle fibers. The microstructured edible films were made using micromolding technology. A micromold was tailor-made using a laser cutting machine to obtain parallel fibers with a diameter in the range of 70-90 µm. Edible films were made by means of solvent casting using non-mammalian biopolymers. Myoblasts were cultured on flat and microstructured films at three cell densities. Cells on the microstructured films grew with a muscle fiber morphology, but in the case of using the flat film, they only produced unorganized cell proliferation. Myogenic markers were assessed using quantitative polymerase chain reaction. After 14 days, the expression of desmin, myogenin, and myosin heavy chain were significantly higher in microstructured films compared to the flat films. The formation of fiber morphology and the high expression of myogenic markers indicated that a microstructured edible film can be used for the production of in vitro meat.

Conceptual evolution and scientific approaches about synthetic meat

Cellular agriculture has been considered a mechanism to enable the generation of animal protein in the laboratory. Notwithstanding, this emerging technology, still on an experimental scale, is imbued with speculations, paradoxes, and ambiguities. So, the objective of this research was to analyze how synthetic meat is considered in the scientific context from the perspective of cellular agriculture considering its trajectory and its approaches. For this, we used a systematic review of the literature with detailed analysis of 109 manuscripts and application of network analysis of co-citations and predominance. This paper has constructed a historical overview of the conceptual evolution of science concerning synthetic meat from its emergence to the present day. We also verified and categorized the research about synthetic meat into three distinct approaches: (1) environmental and health; (2) technical and economic feasibility of the production process; and (3) social and market. This research maximizes the understanding of synthetic meat and its stage of technological and economic development to make commercial production feasible. Aside from that, it has brought insights about synthetic meat and this knowledge can be used by the conventional meat industries.

3D Bioprinting in Skeletal Muscle Tissue Engineering

Skeletal muscle tissue engineering (SMTE) aims at repairing defective skeletal muscles. Until now, numerous developments are made in SMTE; however, it is still challenging to recapitulate the complexity of muscles with current methods of fabrication. Here, after a brief description of the anatomy of skeletal muscle and a short state-of-the-art on developments made in SMTE with "conventional methods," the use of 3D bioprinting as a new tool for SMTE is in focus. The current bioprinting methods are discussed, and an overview of the bioink formulations and properties used in 3D bioprinting is provided. Finally, different advances made in SMTE by 3D bioprinting are highlighted, and future needs and a short perspective are provided.

Edible Scaffolds Based on Non-Mammalian Biopolymers for Myoblast Growth

In vitro meat has recently emerged as a new concept in food biotechnology. Methods to produce in vitro meat generally involve the growth of muscle cells that are cultured on scaffolds using bioreactors. Suitable scaffold design and manufacture are critical to downstream culture and meat production. Most current scaffolds are based on mammalian-derived biomaterials, the use of which is counter to the desire to obviate mammal slaughter in artificial meat production. Consequently, most of the knowledge is related to the design and control of scaffold properties based on these mammalian-sourced materials. To address this, four different scaffold materials were formulated using non-mammalian sources, namely, salmon gelatin, alginate, and additives including gelling agents and plasticizers. The scaffolds were produced using a freeze-drying process, and the physical, mechanical, and biological properties of the scaffolds were evaluated. The most promising scaffolds were produced from salmon gelatin, alginate, agarose, and glycerol, which exhibited relatively large pore sizes (~200 μm diameter) and biocompatibility, permitting myoblast cell adhesion (~40%) and growth (~24 h duplication time). The biodegradation profiles of the scaffolds were followed, and were observed to be less than 25% after 4 weeks. The scaffolds enabled suitable myogenic response, with high cell proliferation, viability, and adequate cell distribution throughout. This system composed of non-mammalian edible scaffold material and muscle-cells is promising for the production of in vitro meat.