Electrospun eri silk fibroin scaffold coated with hydroxyapatite for bone tissue engineering applications

Abstract

Natural biomaterials such as collagen, silk fibroin, and chitosan, and synthetic biopolymers such as polylactic acid, polycaprolactone, polyglycolic acid, and their copolymers are being used as scaffold for tissue engineering applications. In the present work, a fibrous mat was electrospun from eri silk fibroin (ESF). A composite of hydroxyapatite (Hap) and the ESF scaffold was prepared by soaking the ESF scaffold in a solution of calcium chloride and then in sodium diammonium phosphate. The average tensile stress of the pure ESF and hydroxyapatite-coated ESF scaffold (ESF-Hap) was found to be 1.84 and 0.378 MPa, respectively. Pure ESF and ESF-Hap scaffolds were evaluated for their characteristics by a themogravimetric analyzer and Fourier transform infrared spectroscope. The crystallinity and thermal stability of the ESF-Hap scaffold were found to be more than that of uncoated eri silk nanofiber scaffold. The water uptake of the pure ESF and ESF-Hap scaffolds was found to be 69% and 340%, respectively, in distilled water as well as phosphate buffer saline. The hemolysis percentage of both scaffolds was less than 5%, which indicate their good blood compatibility. The cytocompatibility studied by 3-(4,5-dimethyl) thiazol-2-yl-2,5-dimethyl tetrazolium bromide assay showed that the scaffold is biocompatible. To assess cell attachment and growth on the scaffold, human mesenchymal stem cells were cultured on the scaffolds. The results from scanning electron microscopy and fluorescent microscopy showed a notable cellular growth and favorable morphological features. Hence, the ESF-Hap scaffold is better suited for cell growth than the pure ESF scaffold.Electronic supplementary materialThe online version of this article (doi:10.1186/2194-0517-2-6) contains supplementary material, which is available to authorized users.

A porous hydroxyapatite scaffold for bone tissue engineering: Physico-mechanical and biological evaluations

“…Additionally, the porosity of the material may play an important role in the water uptake; the substitute is considered a non-porous material, but the ionic exchange with the medium provokes its degradation and the formation of micro-porosities that allow water uptake [6,49]. Furthermore, our water uptake values were lower compared to those obtained in other studies on materials made of fibroin and calcium phosphates, which are usually between 42% and 70% [46,47].…”

“…4c and 4d) were similar among replicates, as in the degradation test, noting the lack of a direct relationship between the concentration of fibroin and the water uptake. Fibroin is a hydrophobic polymer, while HA is hydrophilic [46,47]. Although there is no point of comparison to determine whether these values are favorable or not, a high percentage water uptake is not beneficial in injectable bone substitutes, since it directly influences their degradation by collapsing the material, mainly when it is hydrophilic, as is the case of HA; in this case, the addition of small percentages of fibroin allows a moderate water uptake due to its hydrophobic nature [46,48].…”

“…Fibroin is a hydrophobic polymer, while HA is hydrophilic [46,47]. Although there is no point of comparison to determine whether these values are favorable or not, a high percentage water uptake is not beneficial in injectable bone substitutes, since it directly influences their degradation by collapsing the material, mainly when it is hydrophilic, as is the case of HA; in this case, the addition of small percentages of fibroin allows a moderate water uptake due to its hydrophobic nature [46,48]. Additionally, the porosity of the material may play an important role in the water uptake; the substitute is considered a non-porous material, but the ionic exchange with the medium provokes its degradation and the formation of micro-porosities that allow water uptake [6,49].…”

Chitin, Chitosan, and Silk Fibroin Electrospun Nanofibrous Scaffolds: A Prospective Approach for Regenerative Medicine

“…However, blending with more than 30 % (by weight) of cellulose acetate, the spinning process was seriously deteriorated producing discontinuous and tacky fibers with beads and dendritic structures. It was also observed that the thermal and mechanical properties were improved by the addition of cellulose acetate up to 10 % [173].…”

Silk Protein-Based Membrane for Guided Bone Regeneration

“…HA is the main inorganic component of natural bone and has biocompatible, biodegradable, and osteoconductive properties [89,90]. It provides higher mechanic strength and stability in the membrane [91].…”