Multilayered blow-spun vascular prostheses with luminal surfaces in Nano/Micro range: the influence on endothelial cell and platelet adhesion

Abstract

Background In this study, two types of polyurethane-based cylindrical multilayered grafts with internal diameters ≤ 6 mm were produced by the solution blow spinning (SBS) method. The main aim was to create layered-wall prostheses differing in their luminal surface morphology. Changing the SBS process parameters, i.e. working distance, rotational speed, volume, and concentration of the polymer solution allowed to obtain structures with the required morphologies. The first type of prostheses, termed Nano, possessed nanofibrous luminal surface, and the second type, Micro, presented morphologically diverse luminal surface, with both solid and microfibrous areas. Results The results of mechanical tests confirmed that designed prostheses had high flexibility (Young’s modulus value of about 2.5 MPa) and good tensile strength (maximum axial load value of about 60 N), which meet the requirements for vascular prostheses. The influence of the luminal surface morphology on platelet adhesion and the attachment of endothelial cells was investigated. Both surfaces did not cause hemolysis in contact with blood, the percentage of platelet-occupied area for Nano and Micro surfaces was comparable to reference polytetrafluoroethylene (PTFE) surface. However, the change in morphology of surface-adhered platelets between Nano and Micro surfaces was visible, which might suggest differences in their activation level. Endothelial coverage after 1, 3, and 7 days of culture on flat samples (2D model) was higher on Nano prostheses as compared with Micro scaffolds. However, this effect was not seen in 3D culture, where cylindrical prostheses were colonized using magnetic seeding method. Conclusions We conclude the produced scaffolds meet the material and mechanical requirements for vascular prostheses. However, changing the morphology without changing the chemical modification of the luminal surface is not sufficient to achieve the appropriate effectiveness of endothelialization in the 3D model.

Characterization of Blow-Spun Polyurethane Scaffolds–Influence of Fiber Alignment and Fiber Diameter on Pericyte Growth

“…Representative SEM images of materials surface morphology (Figures 2−4) show typical morphology of fibrous PU materials produced by SBS method, characterized by the presence of fibers and single defects in the form of stains. 28,32,34 There were no significant differences in the fiber alignment, depending on the rotation speed of the collector in materials with an average fiber diameter of 200 nm (Figure 2). Differences in fiber alignment appeared in the SEM images of the materials with average fiber diameters of 500 and 1000 nm.…”

“…Due to their high mechanical strength and degradation rate, PUs are attractive materials for tissue engineering applications, especially in vascular graft designing,. − Solution blow spinning (SBS) is an emerging technique for fiber production that allows the fabrication of morphologically various well-controlled fibrous architectures that are increasingly used in tissue engineering . The properties of fibrous materials produced using this method can be easily customized to meet the requirements of tissue engineering applications. , Heart, bone, skin, and vascular scaffolds have been widely produced using SBS. ,− …”

“…Several studies have been performed to define the influence of SBS process parameters, such as the polymer solution concentration, gas pressure, polymer solution flow rate, rotation speed of the collector, working distance, and nozzle design, on the fiber and fibrous material properties. , It was concluded that there are dependent characteristics for each parameter (e.g., solution concentration influences fiber diameter and pore size, increasing the collector rotational speed results in fiber orientation, and reducing the working distance reduces the porosity of the material), although the final properties of the fibrous scaffold result from the utilized polymer and the overall combination of all process parameters.…”

Advances in Biomedical Applications of Solution Blow Spinning

“…The blow-spun mats showed a 3D fibrous porous structure similar to that of the ECM of mammalian tissue. More recently, Łopianiak et al developed non-thrombogenic vascular grafts based on PU by means of a multistep SBS method [127]. The influence of the luminal surface morphology on platelet adhesion and the attachment of endothelial cells was investigated by changing the morphology of the fibers according to the SBS processing parameters (mainly working distance, rotational speed, and polymer concentration).…”

“…Neither micro nor nanofibers caused hemolysis in contact with blood, and the percentage of plateletoccupied areas for both types of surfaces was comparable to the reference polytetrafluoroethylene (PTFE), used in vascular implants and favored the growth and differentiation of endothelial cells. More recently, Łopianiak et al developed non-thrombogenic vascular grafts based on PU by means of a multistep SBS method [127]. The influence of the luminal surface morphology on platelet adhesion and the attachment of endothelial cells was investigated by changing the morphology of the fibers according to the SBS processing parameters (mainly working distance, rotational speed, and polymer concentration).…”