Lockdown loaves show growth potential

6mm biopsy punch bread feature
Baking the perfect bread – for cell growth. Credit: Andrew Pelling

As any baking enthusiast will tell you, it’s all about the crumb. In the case of science, the porous nature of the humble bread crumb was the perfect structure for a scaffold.

Scaffolds are the literal basis of regenerative medicine. They’re the structure that supports living cells, and developing novel materials suitable for them is a growing area within bioengineering. 

Growing cell tissues on scaffolds allows them to be used in a variety of biomedical applications, from restoring damaged tissue to creating skin grafts. The burgeoning field of lab-grown meats is another scaffold-grown cell application. 

Throughout the COVID-19 lockdown, some carb-loving engineers from the University of Ottawa in Canada who’d previously worked on plant-based scaffolds saw the potential in their baked goods, as published on the pre-print server bioRxiv. 

Scaffold technology has developed from animal-based to plant-based to new explorations with custom 3D-printing. Scaffolds comprised of gluten proteins from wheat have been previously shown to support cell growth. 

The winning recipe for cellular growth proved to be Irish soda bread.

F1. Large
Recipe for success. Scale bar = 2mm. Credit: Pelling Lab

Although bread is typically made from yeasty goodness, in the case of scaffolds, yeast cells would interfere with other cell growth. The baking powder in the soda bread recipe was used as the leavening agent to create the desired  scaffold structure.

“The porous structure of the crumb allows for the migration of cells within the bread, which consequently makes it an appealing biomaterial,” write the researchers, led by Andrew Pelling from the Pelling Lab

Turning soda bread into a cell-culture scaffold required a few more recipe steps. Proving that it is okay to dodge bread crusts, the researchers extracted the perfect crumb from within the loaf with a 6mm biopsy punch, then carefully sliced it into discs. 

Their bread scaffolds remained intact over the course of two weeks in cell culture, could support cell proliferation, and remained viable. 

The experiments also demonstrated that their soda bread could support a number of mammalian cell types, including mouse fibroblasts, muscle myoblasts, and bone pre-osteoblasts. 

The benefits of bread- over plant-based scaffolds for tissue engineering are threefold: making bread takes less time, the ingredients are readily available, and they’re significantly cheaper than the chemicals necessary for other types of biomaterials. 

This bread-scaffold success has baked in promising possibilities for broad application. 

How to bake perfect Irish soda bread for cell scaffolds

The Canadian researchers say their approach is based “on a common soda bread recipe found widely on the internet”. 

  1. Preheat oven to 205°C.
  2. In a ceramic bowl, mix together 120g of all-purpose flour, 2g of iodised table salt and 10g of baking powder.
  3. Heat 70mL of water in a microwave until the temperature of the water is ~75°C and then add to the flour mix. 
  4. Combine the mixture to form a dough and shape into a ball. Knead for 3 minutes, adding flour as needed to reduce sticking.
  5. Flatten dough into a circular disk with the height of approximately 2.5cm and place in a glass bread pan lined with parchment paper.
  6. Bake in oven for 30 minutes. 
  7. Allow to cool – and then eat! (Or store in a resealable plastic bag at −20°C until use as a scaffold). 

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