Researchers at the Moscow Institute of Physics and Technology have discovered that spider silk can be used as a material for growing myocardial cells outside the body. Instead of farming spiders though, the team genetically engineered yeast cells to produce the primary proteins that are inside spider silk. They isolated these spindroids, and electrospun them to produce a fiber mesh. They then seeded rat heart cells into the new material and monitored their growth, watching for signs of normal cardiac behavior.
The team discovered that the cells grew within the substrate and formed functional layers of tissue that contracted in unison and passed electrical signals. The new mesh material is non-toxic and is extremely strong while being highly flexible. These characteristics point toward clinical applications of the spindroid mesh, potentially allowing for the manufacture of replacement heart tissue that can be perfectly created for individual patients’ unique needs.
From the study in PLOS ONE:
While the outstanding mechano-elastic features of the silk fibers as well as the potential power of the genetic manipulations with silk proteins are well documented, especially, in the works of Kundu, et al., the physiological characteristics of the silk-based engineered excitable cardiac tissue are not yet fully studied. For example, there is an apparent lack of knowledge of electrophysiological characteristics of the cardiac tissue grown on the silk proteins. Thus, we focused on the excitable features of the grown cardiac tissue layers: the main goal of the study was to prove, that besides only survival and growth, the engineered cardiac tissue is able to transmit organized electrical signals for the orchestrated contracting, potentially taking part in the crucial heart’s job: pumping blood.
For this purpose, isolated neonatal rat cardiomyocytes were seeded on the fiber matrices and cultured to form confluent cardiac monolayers. Cardiac cells successfully adhered and grew on the spidroin fiber meshes obtained by electrospinning, forming contractile and excitable cell network supported by the spidroin fibers. We tested adherence of the cardiac cells to the different types of recombinant spidroins, containing and non-containing RGDS motif. The excitability and conduction of the excitation waves in the grown cardiomyocyte layers were analyzed with the aid of optical mapping, i.e., recording of the excitation waves with fluorescent markers
(hat tip: Gizmodo)