Myocardial
infarction (MI) is one of the leading causes of death
worldwide. The complications associated with MI can lead to the formation
of nonconductive fibrous scar tissues. Despite the great improvement
in electroconductive biomaterials to increase the physiological function
of bio-engineered cardiac tissues in vivo, there are still several
challenges in creating a suitable scaffold with appropriate mechanical
and electrical properties. In the current study, a highly hydrophilic
fibrous scaffold composed of polycaprolactone/chitosan/polypyrrole
(PCP) and combined with functionalized graphene, to provide superior
conductivity and a stronger mechanical cardiopatch, is presented.
The PCP/graphene (PCPG) patches were optimized to show mechanical
and conductive properties close to the native myocardium. Also, the
engineered patches showed strong capability as a drug delivery system.
Heparin, an anticoagulant drug, was loaded within the fibrous patches,
and the adsorption of the bovine serum albumin (BSA) protein was evaluated.
The optimized cardiopatch shows great potential to be used to provide
mechanical support and restore electromechanical coupling at the site
of MI to maintain a normal cardiac function.
In this study, polycaprolactone/chitosan/polypyrrole (PCL/chitosan/PPy) conductive composite nanofibrous scaffold is fabricated. For this purpose, initially, a polymer blend of PCL/chitosan (7:3) and (4:1) was selected and then 1, 2.5, 5 and 7.5 wt% of PPy was added to each solution. A range of techniques were applied to study the chemical, physical and biodegradability properties of the resultant fibrous mats. According to scanning electron microscope (SEM) images, with the addition of PPy to the PCL/chitosan blend, the size of the fiber diameter decrease. There was significant increase in the electrical conductivity of the mats such that the electrical conductivity of PCL/chitosan was around 0.1 S/cm but increased to 2 S/cm in biological environment with the addition of 7.5% PPy. Hydrophobicity was found to improve with the addition of PPy as water contact angle changed from 120 ± 10 for PCL/chitosan to 133 ± 18 at 7.5% PPy. The incorporation of PPy within the PCL/chitosan matrix was found to positively influence the overall properties of nanofibrous structure, making them suitable for biomedical applications.
Electroconductive scaffolds can be a promising approach to repair conductive tissues when natural healing fails. Recently, nerve tissue engineering constructs have been widely investigated due to the challenges in creating a structure with optimized physiochemical and mechanical properties close to the native tissue. The goal of the current study was to fabricate graphene-containing polycaprolactone/gelatin/polypyrrole (PCL/gelatin/PPy) and polycaprolactone/polyglycerol-sebacate/polypyrrole (PCL/PGS/PPy) with intrinsic electrical properties through an electrospinning process. The effect of graphene on the properties of PCL/gelatin/PPy and PCL/PGS/PPy were investigated. Results demonstrated that graphene incorporation remarkably modulated the physical and mechanical properties of the scaffolds such that the electrical conductivity increased from 0.1 to 3.9 ± 0.3 S m −1 (from 0 to 3 wt % graphene) and toughness was found to be 76 MPa (PCL/gelatin/PPy 3 wt % graphene) and 143.4 MPa (PCL/PGS/PPy 3 wt % graphene). Also, the elastic moduli of the scaffolds with 0, 1, and 2 wt % graphene were reported as 210, 300, and 340 kPa in the PCL/gelatin/PPy system and 72, 85, and 92 kPa for the PCL/PGS/PPy system. A cell viability study demonstrated the noncytotoxic nature of the resultant scaffolds. The sum of the results presented in this study suggests that both PCL/gelatin/PPy/graphene and PCL/PGS/PPy/graphene compositions could be promising biomaterials for a range of conductive tissue replacement or regeneration applications.
Tissue engineering approach aims to overcome the transplant drawbacks and facilitate tissue repair and regeneration. Here, a new conductive, highly porous, and flexible polycaprolactone/gelatin/polypyrrole/graphene 3D scaffolds for nerve tissue repair is presented. A simple and efficient porogen leaching fabrication method is
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