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.

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The cultivated silk, mulberry, is being used as biomaterial in different forms. Eri, tasar and muga are some of the known wild silk varieties. The studies on biomedical applications of electrospun mats produced from these wild silks are limited though few studies on eri silk are available. In this work, comparison was made between eri and tasar silk fibroin scaffolds for biomedical application. The scaffolds were produced from eri silk fibroin (ESF) and tasar silk fibroin (TSF) by electrospinning method and they were treated with ethanol to improve dimensional stability. Ethanol treatment increased the crystallinity% of both ESF and TSF scaffolds. The crystallinity percentage of the ESF and TSF scaffolds was found to be 46.7 and 42.8 % respectively. Thermal stability was higher for ESF than that of TSF scaffold. The hemolytic % of ESF and TSF scaffolds was found to be 1.3 and 7.7 % respectively. The platelet adhesion on the surface of ESF scaffold was lower than that found on TSF scaffold. Better fibroblast cell attachment, binding and spreading was found on the ESF scaffold. The cell viability on ESF scaffold was 83.78 % and in TSF was 78.01 % for 48 h. The results showed that ESF electrospun scaffold can be considered as a better biomaterial for biomedical applications compared to that of TSF scaffold.

Electrospun scaffolds are being widely studied for its potential application in tissue engineering because of its nanostructure that mimics the extracellular matrices. Although it has several advantages, it lacks mechanical strength and causes structural deformation during handling of the scaffold. It is well known that the textile-based structures like woven and nonwoven fabrics have excellent structural stability. In this study, a woven and a hydroentangled nonwoven fabric were fabricated from eri silk fibroin and their characteristics were compared with electrospun scaffold. The functional groups, contact angle, thermal degradation, hemocompatibility studies showed that all the three scaffolds can be used as biomaterials. The pore and pore size distribution were better with electrospun scaffold due to smaller fiber diameter and more number of layers of fibers. The tensile behaviour was found to be better for woven and nonwoven scaffolds. The enzymatic degradation showed that the stability of woven and nonwoven scaffolds were better and electrospun scaffold degrades and disintegrates quickly. Mouse 3T3 L1 fibroblast and Human Wharton’s jelly Mesenchymal Stem Cells adhered on all the three scaffolds and a higher attachment and growth coverage were obtained on the electrospun and nonwoven scaffolds. It was found that the hydroentangled nonwoven silk scaffold exhibited similar biological characteristics as that of electrospun scaffold and also had higher mechanical strength and structural stability. Hence, it is inferred that the hydroentangled nonwoven scaffold can be considered as a suitable structure for tissue engineering applications.

A scaffold, synthesized from bio-degradable polymers and Bombyxmori silk fibroin in the form of films and fibrous assemblies, has been used as the bio-material for in-vivo applications. In the present work, the scaffold was prepared from the fibroin of Indian eri silk via the electrospinning method. The diameter of the fibre produced was in the range of 300 to 900 nm. The scaffold was subjected to ethanol treatment to improve its dimensional stability, as there was the problem of curling and shrinking when it was treated with solutions used for the cell culture. The scaffold was characterized for surface, thermal and tensile properties. The dimensional stability of the scaffold improved and the porosity reduced, due to the treatment of the scaffold with ethanol. The average failure stress of the raw and ethanol treated scaffold was 2.34 MPa and 4.91 MPa respectively and the mean strain was 13.63 % and 7.91 % respectively. Bone marrow stromal cells were isolated from the bone marrow of Swiss albino mice, and cultured on the ethanol treated electrospun fibrous scaffold. Scanning electron microscopy of the culture was carried out to evaluate the attachment and growth of cells on the scaffold at different incubation periods. Mouse bone marrow stromal cells adhered and grew on the electrospun fibrous scaffold prepared from eri silk fibroin, and the cell density increased with increasing incubation periods.