Homemade Bread: Repurposing an Ancient Technology forin vitroTissue Engineering

Abstract

Cellular function is well known to be influenced by the physical cues and architecture of their three dimensional (3D) microenvironment. As such, numerous synthetic and naturally-occurring biomaterials have been developed to provide such architectures to support the proliferation of mammalian cells in vitro and in vivo. In recent years, our group, and others, have shown that scaffolds derived from plants can be utilized for tissue engineering applications in biomedicine and in the burgeoning cultured meat industry. Such scaffolds are straightforward to prepare, allowing researchers to take advantage of their intrinsic 3D microarchitectures. During the 2020 SARS-CoV-2 pandemic many people around the world began to rediscover the joy of preparing bread at home and as a research group, our members participated in this trend. Having observed the high porosity of the crumb (the internal portion of the bread) we were inspired to investigate whether it might support the proliferation of mammalian cells in vitro. Here, we develop and validate a yeast-free “soda bread” that maintains its mechanical stability over two weeks in culture conditions. The scaffolding is highly porous, allowing the 3D proliferation of multiple cell types relevant to both biomedical tissue engineering and the development of novel future foods. Bread derived scaffolds are highly scalable and represent a surprising new alternative to synthetic or animal-derived scaffolds for addressing a diverse variety of tissue engineering challenges.

Cultivating Multidisciplinarity: Manufacturing and Sensing Challenges in Cultured Meat Production

“…Some of the newest alternatives are presented in the pre-print server-published work by Holmes et al describing bread-derived scaffolds in the form of a highly porous crumb (the soft, inner part of the bread) [ 140 ]. Using this type of scaffold, multiple cell types relevant to the development of novel future foods can proliferate in 3D.…”

“…This yeast-free type of bread scaffold (“soda bread”) was able to maintain its mechanical stability over two weeks in culture conditions. Importantly, bread-derived scaffolds are cost-efficient and convenient for scale-up [ 140 ].…”

Colonization versus encapsulation in cell-laden materials design: porosity and process biocompatibility determine cellularization pathways

“…By contrast, because of the harsh conditions used for bubbles generation (chemical reactions for the internal and high pressure for the external processes respectively), it is poorly adapted to cell encapsulation [78,79]. A recent-and unlikely-example of cellularization of materials obtained by gas foaming is that of stale bread-which by all means can be compared to gas foaming generated by baking powder-that was successfully seeded with mouse fibroblasts, myoblasts and pre-osteoblasts [80]. Figure 2 depicts the processing window for gas foaming.…”

Bioactivity – Symphony or Cacophony?

“…Such scaffolds are clearly effective, but whilst they may provide a surface with compatible or 'recognized' chemistry it is hard to see how these could be labelled bioactive, with the implication of biochemical modulation. The topological aspect has been stressed for bread, [8] yet the effect has been ascribed to 'bioactivity' on the basis of the simulated body fluid test. [9] This makes no sense.…”

“…Overall, the concept seems to be that a surface or scaffold is to be perceived as benign by the growing tissue, in other words completely ignored as of no consequence in itself, only the space matters (cf. the bread scaffold discussed above [8]). Properly inert and uninterfering such a scaffold is essentially invisible except for the physical contact providing a niche.…”