Biodegradable Scaffold Fabricated of Electrospun Albumin Fibers: Mechanical and Biological Characterization

Abstract

Natural polymers share recognition sequences that promote cell adhesion, rendering them attractive candidates for scaffolding in tissue engineering applications. However, challenges remain with regard to the fabrication of robust and porous structures of such raw materials for the design of extracellular matrix (ECM) mimics of living tissues. In this study, we present a fibrous scaffold that solely consists of albumin, the most abundant protein in mammalian blood plasma. The scaffold was fabricated using the electrospinning method, and resulted in microscale fibers that demonstrated mechanical properties which were similar to those of elastin fibers, a common component of connective tissue ECM. Albumin scaffolds proved nontoxic and supported adhesion and the spreading of fibroblasts, muscle cells, and endothelial cells (ECs) in vitro. In vivo studies demonstrated ∼50% biodegradation of the albumin scaffolds within 3 weeks of implantation. In addition, it was found that the fibers were encapsulated by dense fibrosis and evoked a weak inflammatory response, similar to that triggered by poly(L-lactide)/poly(lactic-co-glycolic acid) scaffolds. Albumin tubular structures fabricated to mimic blood vessels successfully guided the formation of blood vessel-like bi-layer structures made of fibroblasts and ECs. Thus, albumin scaffolds featuring biologically relevant characteristics pose a readily applicable alternative to synthetic scaffolding materials.

Role of tissue engineering in tendon reconstructive surgery and regenerative medicine: Current concepts, approaches and concerns

“…Generally, they can be divided into three major groups including biological (natural), synthetic and hybrid materials 12,41,42 . Biological materials such as collagen, elastin, gelatin, chitosan, albumin, alginate, fibrin and chondroitin sulphate have been shown to be effective in tendon healing 36,40,43,44 . Actually, these materials are biocompatible and biodegradable…”

“…By this technology, it is possible to align the polymerised fibres of the scaffold (Fig. 4F) 2,44 . Also, the diameter of the polymerised fibres can be designed to produce different ranges of fibres from nanometric to micrometric scales 54 …”

“…Both these characteristics can be controlled and ordered when the new design is approached 40,44 . The tendon-engineered scaffolds should have fibre diameters varying between nano-scale and micro-scale 57,58 .…”

“…It has been shown that controlling the scaffold fibre diameter is critical in the design of scaffolds for functional and guided connective tissue repair, and provides new insights into the role of matrix parameters in guiding soft tissue healing 57,58 . A tendon's normal architecture is composed of collagen fibrils with nanometric diameters and collagen fibres and fibre bundles with different micrometric diameters.Therefore, a suitable scaffold for tendon tissue engineering should consist of both micro and nanoscale moderately to highly aligned fibres to be effective in guiding both the nano and microstructure of the newly regenerated tissue after implantation 14,40,44 . Pore size is another important factor 40 .…”

“…These characteristics are mainly dependent on the above mentioned factors 44 . With these characteristics, the implant is able to absorb the cellular structures and healing mediators in its architecture and maintain them for a long time 56 .…”