ELECTROSPUN NANOFIBERS AS SCAFFOLDS FOR MANUFACTURING CULTURED MEAT
MELİKE GOZUTOK[1]
INTRODUCTION
Cultured meat (CM), also known as in vitro meat, artificial meat, cultivated meat, cell-based meat, lab-grown meat, clean meat, or synthetic meat, is generally produced by culturing cells in vitro instead of animal-derived tissue harvesting [1-2]. Artificial meat can effectively minimize the consumption ratio of energy, and water as well as greenhouse gas emissions, disease transmission, and the number of animals slaughtered to satisfy the demand for meat. Furthermore, less intimate human-animal encounters will significantly reduce the emergence and incidence of epidemic zoonoses [3-4].
Figure 1. Artificial meat, lab grown meat, in vitro meat
[1] R&D ENGINEER, INOVENSO TECHNOLOGY. (2022)
melike.gozutok@inovenso.com
HISTORY:
Opposite of the general belief, the idea of raising meat in a cultivated environment has always piqued the interest of the general population and it has a long history. In 1931, British statesman Winston Churchill wrote in an essay from 1931 that was published in a number of periodicals and later collected in his book Thoughts and Adventures: “We shall escape the absurdity of growing a whole chicken to eat the breast or wing, by growing these parts separately under a suitable medium” [5-6].
Dutch researcher Willem van Eelen as a prisoner of war during the Second World War independently came up with the idea for cultured meat where he suffered from starvation, leading him to be passionate about food production and food security in 1950s. When he attended the University of Amsterdam, he has been in the lectures where prospects of preserved meat were discussed leading him to do research on cell cultivation. In 2001, University of Amsterdam dermatologist Wiete Westerhof, researcher and businessperson Willem van Eelen, and businessperson Willem van Kooten announced that they had filed for a worldwide patent on a process to produce cultured meat. In this study a matrix of collagen is seeded with muscle cells, which are then bathed in a nutritious solution and induced to divide. At the same year, NASA showed interest and started conducting research about cultivated meat with the goal of allowing astronauts traveling far and wide to grow meat without sacrificing storage and they were able to raise pieces of goldfish and later turkey [7-8].
The first public trial was performed in 2013 by Mark Post at Maastricht University where first cultured beef burger patty was created and it was made from over 20,000 thin strands of muscle tissue, cost over $300,000 and needed 2 years to produce.
Industrial development has been initiated starting from 2011 when many cultured meat start-ups were launched. Memphis Meats (now Upside Foods), launched a video in 2016, showing their cultured beef meatball. An Israeli company, SuperMeat, ran a viral crowdfunding for its work on cultured chicken campaign in 2016. In March 2018, Eat Just claimed to be able to offer a consumer product from cultured meat by the end of 2018. In the same year, a Dutch start-up reported that it had succeeded in growing meat using pluripotent stem cells from animal umbilical cords. The major advantage is that this technique bypasses fetal bovine serum, meaning that no animal has to be killed to produce meat followed by their announcements, an estimated 30 cultured meat startups operated across the world. Integriculture is a Japan-based company working on their CulNet system where their competitors included England based Multus Media and Canadian Future Field. In January 2020, first attempt for the pilot production has been done by Memphis Meats, Just Inc. and Future Meat Technologies [9-10].
In November 2020, SuperMeat opened a ‘test restaurant’ in Israel, right next to its pilot plant; journalists, experts and a small number of consumers could book an appointment to taste the novel food there, while watching the production facility through a glass window. The restaurant was not yet fully open to the public, because as of June 2021 SuperMeat still needed to wait for regulatory approval to start mass production for public consumption, and because the Covid-19 pandemic. On 2 December 2020, the Singapore Food Agency approved the “chicken bites” produced by Eat Just for commercial sale. It marked the first time that a cultured meat product passed the safety review of a food regulator and was widely regarded as a milestone for the industry. In March 2022, cultured meat producers had reached the level of attempting to gain regulatory approval from European Union supranational institutions coming just before mass goods could be sold to consumers [11].
As of 2022, more than 70 companies working in the field of artificial meat, both conducting research and making pilot production and entering the market, were recorded. In 2021, the cultured meat market size was estimated at $1.64 million where it was estimated to reach $2788.1 million in 2030.
TECHNICAL ASPECTS:
In the most basic definition, cultured meat is obtained by preparing a scaffold (molds meant to reflect and encourage the cells to organize into a larger structure), placing the scaffold into a bioreactor, adding the population of cells to the bioreactor, culturing the population of cells in the bioreactor containing the scaffold for a period of time, thereby forming the cultured meat product, and removing the cultured meat product from the bioreactor [12].
Scaffolds are porous 3D structures acting as a template or mold for tissue formation usually, a mimicry of the extracellular matrix (ECM) for cells to attach, proliferate and/or differentiate. The main aim of a scaffold is to facilitate necessary muscles, fat, and connective tissue development. Properties of the final CM products such as texture or taste, could be processed downstream, like current techniques used to process real meat products. The essentials of an ideal scaffold for CM are very similar to that of tissue engineering scaffold technologies, which are biocompatibility, biodegradability, mechanical properties such as pore size, mechanical strength, scaffold architecture and manufacturing technologies [13].
Some parameters should be carefully considered when designing scaffolds for cultured meat for example biomaterial used for the scaffold manufacturing should cell support, technological feasibility, safety, sustainability, and commercial viability. The chosen biomaterial must provide specific mechanical and biochemical features that should guide cell attachment, morphology, proliferation, and other cellular activities to support the cultured cells. Another important point, the biomaterials chosen for cultured meat scaffolds should also contribute to the appearance, taste, and nutritional values of the final structure, which aims to replicate the features of animal-derived meat [13-15]. Moreover, the scaffold is being affected by the microenvironment provided by the chosen biomaterials that support or even direct cells’ differentiation into meat-related cell types such as myocytes, adipocytes, or fibroblasts.
The technological feasibility and processibility is another critical factor for CM. The process should be compatible between a certain biomaterial to the desired manufacturing technology. Scientist have been using some methods to produce CM scaffolds like, 3D bioprinting, solvent casting, stereolithography, freeze-drying, gas foaming, extrusion, selective-laser sintering, and electrospinning [16].
Figure 2. Scaffold preparation techniques in CM [16].
Electrospinning For Cultured Meat
Electrospinning is a versatile, user friendly, cost-effective, and tunable process; widely used in several application fields such as textiles, nano-devices, filtration, and tissue engineering. Moreover, above all other techniques mentioned above, electrospun products were proven to be manufactured using commercial industrial-scale facilities [17].
For cell-scaffolding applications, the produced porous nano-fibrous scaffolds by electrospinning can mimic the morphology and structure of ECM and provide the high surface area which is an essential feature for cellular adhesion and proliferation. The spatial orientation of the electrospun fibers can be adjusted, that can provide cell-scaffold interactions to control the morphology of the cells grown on the electrospun scaffold. For instance, electrospun fibers can be aligned, inducing the alignment of the cells seeded on them and promoting elongation of muscle cells as well as myogenesis [18].
Figure 3. Electrospinning Technique
The electrospinning of different biopolymers and edible materials has already been established to be used in cultured meat application, including collagen, gelatin, several proteins, chitosan, zein, cellulose, starch, soy isolate, egg albumen, and pullulan. Another advantage of electrospinning is that hybrid electrospun scaffolds can be obtained by mixing two or more materials in a solution-based system. However, despite the versatility and scalable potential of this method, its application for cultivated meat is still an on-going research topic [19].
Needs and advantages of cultured meat
Cultured meat has the potential to greatly reduce animal suffering while satisfying all the nutritional and hedonic requirements of meat eaters. In the case of environmental conditions as energy and nutrients, artificial meat production may reduce 82%-96% of water usage, 78%-96% greenhouse gas emissions, and 99% land use when compared with traditional meat production. Moreover, the chances of foodborne diseases should be lower in an in vitro meat production system due to the extensive monitoring systems and strict quality control rules, detailed manufacturing practice, that are impossible to introduce in modern animal farms, slaughterhouses, or meat packing plants. Besides, CM can be a time-saving process as it takes several weeks for chickens or years for pigs and cows before the meat can be harvested in the current meat production systems while grow the meat in vitro would take significantly lower time. Apart from these, bioreactors for artificial meat production may not need extra space and they could be stacked up in a fabric hall or in a facility, the nutritional costs for cultured meat should be lower than conventional meat. In the future aspects, the long-term space missions such as a settlement on the moon or a flight to Mars will likely involve some food production in situ within a settlement or spacecraft to reduce liftoff weight and its associated costs. Moreover, cultured meat is expected to liberate itself of religious associations, such as Kosher and Halal, making it a universal product equally acceptable to whole spectrum of consumers. Lastly, Cultured meat may be a preferred alternative because it is, unlike other products, animal-derived and with respect to composition most like meat. A small market comprising the vegetarians that do not eat meat for ethical reasons may also be available [20].
Figure 4. Advantages of CM
References
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