Preparing and characterizing cardiac patches

One of the leading causes of death worldwide, heart attack, in other words acute myocardial infarction (MI), is the main cause of coronary heart failure. It usually occurs when the cardiac muscles cannot receive enough oxygen and nutrients due to clogged coronary arteries. After MI, massive cell death occurs in the cardiac muscles and scar tissue is formed. Scar tissue cannot transmit the electrical signals produced during pumping of blood, contrary to what should be in a healthy cardiac muscle. Recently, studies on cardiac patches that are designed to at least provide functional support to the dead cardiac tissue, thus increasing the quality of life of patients after MI and reducing their vital risks, have started to gain importance. Cardiac patches are usually designed as three-dimensional porous membranes using biocompatible biomaterials. Biomaterials made from synthetic or biological polymers help the cells to organize with the surrounding functional tissues. However, due to the poor electrical conductivity of biopolymers, the ability of the patch to perform its electrical conductivity function is limited. In the presented study, conductive and elastic PLA/PCL/Ni₂O₃ nanocomposite cardiac patches that can overcome these limitations were produced by simultaneous and counter elecrospinning of poly(lactic acid) (PLA) and poly(ɛ-caprolactone) polymers which are widely used in tissue engineering applications and approved by the FDA (Food and Drug Administration). Ni2O3 nanoparticles were included to provide conductivity to the patch structure during electrospinning. The chemical structure analysis of the produced patches was made by taking the spectra from the patch samples (FTIR). Surface morphology and fiber structure were evaluated by taking Scanning Electron Microscopy (SEM) images. Density and porosity values of the patches were calculated. Wettability (% Swelling ratios) and biodegradation of patches were determined under in-vitro conditions (pH 7.4, 25°C) in Phosphate Buffer Solution (PBS). The hydrophilic/hydrophobic character of the patch surfaces was determined by taking contact angle measurements. Patch elasticity was characterized using standard tensile tests and patch conductivity was characterized using the 4-point probe technique. As a result of characterization studies it has been concluded that PLA/PCL/Ni₂O₃ cardiac patches have the potential to be used in in-vivo biomedical applications