New moves in lab-grown meat: Researchers grow muscle cells on edible fibers

23 Oct 2019 --- Lab-grown or cultured meat could revolutionize food production, providing a greener, more sustainable, more ethical alternative to large-scale meat production. However, getting lab-grown meat from the petri dish to the dinner plate requires solving several major problems, including how to make large amounts of it and how to make it feel and taste like real meat. Using edible gelatin scaffolds, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have grown rabbit and cow muscle cells that mimic the texture and consistency of meat, providing further evidence that realistic meat products may eventually be mass-produced without the need to raise and slaughter animals.

The news comes at a time when lab-grown meat is in the spotlight. Earlier this week, FoodIngredientsFirst reported the burgeoning technology of the cultured meat space could help address the sustainability fears of a generation that is increasingly vocal about the urgent need for an overhaul in traditional agriculture.

Last month, FoodIngredientsFirst reported that innovators specializing in plant-based and cultivated meat may be eligible for up to US$300,000 in research funding under US non-profit Good Food Institute’s (GFI) Competitive Research Grant Program. 

The latest research on lab-grown meat is published in Nature Science of Food. Kit Parker, the Tarr Family Professor of Bioengineering and Applied Physics at SEAS and senior author of the study, began his foray into food after judging a competition show on the Food Network.

Microscale comparison of gelatin fibers (top) and natural rabbit skeletal muscle (bottom). Scanning electron microscopy images show similar fiber diameter and texture for gelatin scaffolds or skeletal muscle.

“The material-science expertise of the chefs was impressive,” says Parker. “After discussions with them, I began to wonder if we could apply all that we knew about regenerative medicine to the design of synthetic foods. After all, everything we have learned about building organs and tissues for regenerative medicine applies to food. Healthy cells and healthy scaffolds are the building substrates, the design rules are the same, and the ultimate goal is the same: human health.”

“This is our first effort to bring hardcore engineering design and scalable manufacturing to the creation of food,” he comments.

Animal meat consists mostly of skeletal muscle (and fat tissue), which grows in long, thin fibers – as can be seen in the grain of a steak or when shredding pork or chicken. Reproducing these fibers is one of the biggest challenges in bioengineering meat.

“Muscle cells are adherent cell types, meaning they need something to hold onto as they grow,” explains Luke Macqueen, first author of the study and postdoctoral fellow at SEAS and the Wyss Institute for Bioinspired Engineering. 

“To grow muscle tissues that resemble meat, we needed to find a ‘scaffold’ material that was edible and allowed muscle cells to attach and grow in 3D. It was important to find an efficient way to produce large amounts of these scaffolds to justify their potential use in food production.”

“The development of cultured meat involves a number of technical challenges, including the formulation of a scaffold material that can successfully support cells and the development of cell lines that are amenable to cultivation for consumption at scale,” says Kate Krueger, Research Director at New Harvest, a cellular agriculture research institution, who was not involved in the research. 

“The authors of this publication have developed scaffold materials that show great promise in these areas,” she adds. 

To overcome these challenges, the researchers used a technique developed by Parker and his Disease Biophysics Group known as immersion Rotary Jet-Spinning (iRJS), which uses centrifugal force to spin long nanofibers of specific shapes and sizes. The team spun food-safe gelatin fibers to form the base for growing cells. The fibers mimic natural muscle tissue's extracellular matrix – the glue that holds the tissue together and contributes to its texture.

The team seeded the fibers with rabbit and cow muscle cells, which anchored to the gelatin and grew in long, thin structures, similar to real meat. The researchers used mechanical testing to compare the texture of their lab-grown meat to real rabbit, bacon, beef tenderloin, prosciutto and other meat products.

“When we analyzed the microstructure and texture, we found that, although the cultured and natural products had comparable texture, natural meat contained more muscle fibers, meaning they were more mature,” explains Macqueen. 

“Muscle and fat cell maturation in vitro are still a really big challenge that will take a combination of advanced stem cell sources, serum-free culture media formulations, edible scaffolds such as ours, as well as advances in bioreactor culture methods to overcome.”

Still, this research helps pave the way to achieving commercialized fully lab-grown meat is possible.

“Our methods are always improving and we have clear objectives because our design rules are informed by natural meats. Eventually, we think it may be possible to design meat with defined textures, tastes and nutritional profiles – a bit like brewing,” notes Macqueen.

“Moving forward, the goals are nutritional content, taste, texture, and affordable pricing. The long-range goal is reducing the environmental footprint of food,” Parker concludes.

Edited by Elizabeth Green