Researchers from Biophysics departments have expanded greater understanding about the structure of nanofibrous scaffolds, termed nanoscaffolds in a study that is researching heart tissue regeneration. They have studied the structure of a nanofibrous scaffold, as well as its interaction with rat cardiac cells, as part of a study into heart tissue regeneration. The study was published in the journal Acta Biomaterialia.

They discovered that heart muscle cells, known as cardiomyocytes, envelop nanofibres as they grow, while fibroblasts connective tissue cells tend to spread out on fibres forming several focal adhesion sites. Regenerative medicine seeks to repair or replace lost or damaged human cells, tissues, and organs.

Tissue engineering is often the only way to restore the functions of the human heart and achieve recovery.  Creating “patches” for a damaged heart, however, demands more than merely understanding the properties of the corresponding tissue cells; it requires an understanding of their interaction with the substrate, as well as the surrounding solution and neighbouring cells.

Vital for the growth, development, and formation of regenerating tissues is the substrate on which cells are grown. The scaffolds used for cardiac tissue engineering are based on a matrix of polymer nanofibres. Nanofibres vary in terms of elasticity and electrical conductivity, and they may have additional ‘smart’ functions that enable them to release biologically active molecules at a certain stage.

Another application for nanofibres is as a medium for delivering substances into the surrounding cells to induce biochemical changes in them. Studying the interactions between the scaffold and heart cells is therefore essential for choosing the right nanofibre characteristics that would bring an artificial structure closer to that of a living organism.

Researchers studied the structure of cardiomyocytes and fibroblasts grown on a substrate of nanofibres using confocal laser scanning microscopy. Then, using scanning probe nanotomography, a comprehensive 3d model was created. The researchers took cells grown on a substrate of nanofibres and sliced them into 120-nanometre-thick sections.

Firstly, since stronger mechanical adhesion, i.e. cell-scaffold attachment means cells are more stable growing on the substrate, cardiomyocytes will be firmly attached to the scaffold, while fibroblasts will be less stable. Secondly, additional ‘smart’ scaffold functions, such as the release of growth factors protein molecules that stimulate cellular growth will also differ depending on the cell type.

In the case of cardiomyocytes, the released substances will diffuse directly from the fibre through the cell membrane and into the cytoplasm. Thirdly, cardiomyocytes isolate the polymer fibres from the surrounding solution. Since they are responsible for the transfer of electromagnetic waves within the heart and therefore for heart contractions immersing the fibres of the scaffold completely in cardiomyocytes will enable researchers to test the electrical conductivity of the cells.

Further investigation into the mechanisms of cell-substrate interactions, will enable the creation of nanofibers that would provide cells with the properties needed to form regenerative tissues.