Effect of sequential electrospinning and co-electrospinning on morphological and fluid mechanical wall properties of polycaprolactone and bovine gelatin scaffolds, for potential use in small diameter vascular grafts

Abstract

Background Nowadays, the engineering vascular grafts with a diameter less than 6 mm by means of electrospinning, is an attracted alternative technique to create different three-dimensional microenvironments with appropriate physicochemical properties to promote the nutrient transport and to enable the bioactivity, dynamic growth and differentiation of cells. Although the performance of a well-designed porous wall is key for these functional requirements maintaining the mechanical function, yet predicting the flow rate and cellular transport are still not widely understood and many questions remain open about new configurations of wall can be used for modifying the conventional electrospun samples. The aim of the present study was to evaluate the effect of fabrication techniques on scaffolds composed of bovine gelatin and polycaprolactone (PCL) developed by sequential electrospinning and co-electrospinning, on the morphology and fluid-mechanical properties of the porous wall. Methodology For this purpose, small diameter tubular structures were manufactured and experimental tests were performed to characterize the crystallinity, morphology, wettability, permeability, degradability, and mechanical properties. Some samples were cross-linked with Glutaraldehyde (GA) to improve the stability of the gelatin fiber. In addition, it was analyzed how the characteristics of the scaffold favored the levels of cell adhesion and proliferation in an in vitro model of 3T3 fibroblasts in incubation periods of 24, 48 and 72 h. Results It was found that in terms of the morphology of tubular scaffolds, the co-electrospun samples had a better alignment with higher values of fiber diameters and apparent pore area than the sequential samples. The static permeability was more significant in the sequential scaffolds and the hydrophilic was higher in the co-electrospun samples. Therefore, the gelatin mass losses were less in the co-electrospun samples, which promote cellular functions. In terms of mechanical properties, no significant differences were observed for different types of samples. Conclusion This research concluded that the tubular scaffolds generated by sequential and co-electrospinning with modification in the microarchitecture could be used as a vascular graft, as they have better permeability and wettability, interconnected pores, and a circumferential tensile strength similar to native vessel compared to the commercial graft analyzed.

Chain-End Functionalization of Poly(ε-caprolactone) for Chemical Binding with Gelatin: Binary Electrospun Scaffolds with Improved Physico-Mechanical Characteristics and Cell Adhesive Properties

“…In recent publications, two types of solvents have been used for ES of PCL/Gt composites, fluorinated alcohols [ 29 , 30 , 31 , 33 , 35 , 36 , 39 , 41 , 43 , 45 , 49 , 51 ] and carboxylic acids (AcOH, HCOOH) [ 32 , 34 , 37 , 38 , 40 , 42 , 46 , 47 , 48 , 50 , 65 ]. In the present study, we set ourselves the task to provide rather high (but not excessive) chemical bonding between NHS-functionalized PCL and Gt macromolecules as a result of the reaction of NHS-terminated PCL with amino groups of Gt.…”

“…Gelatin (Gt) is a hydrophilic and non-immunogenic natural-origin polymer that promotes cell adhesion, differentiation, and proliferation [ 21 ]. PCL/Gt-based ES composite nano- and microfibers seem to be promising for different biomedical applications [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ], and the studies of PCL/Gt ES scaffolds have intensified significantly in recent years [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ].…”

Functional electrospun nanofibers: fabrication, properties, and applications in wound-healing process

“…ES in drug delivery mainly includes sequential ES, 141 synchronized ES, 142 coaxial ES, 143 and side-by-side ES 144 ( Fig. 8 and Table 7 ).…”

The History of Electrospinning: Past, Present, and Future Developments

“…This simple tweaking of mono-axial electrospinning process can enhance the complexity of the attained electrospun mats, producing structures such as layerby-layer or mixed membranes that encompass properties derived from two or more polymer solutions in a layer-by-layer configuration. [123,124] Table 5. Advantages and disadvantages of mono-axial electrospinning.…”