Non‐bioengineered silk gland fibroin protein: Characterization and evaluation of matrices for potential tissue engineering applications

Abstract

The possibility of using wild non-mulberry silk protein as a biopolymer remains unexplored compared to domesticated mulberry silk protein. One of the main reasons for this was for not having any suitable method of extraction of silk protein fibroin from cocoons and silk glands. In this study non-bioengineered non-mulberry silk gland fibroin protein from tropical tasar silkworm Antheraea mylitta, is regenerated and characterized using 1% (w/v) sodium dodecyl sulfate (SDS). The new technique is important and unique because it uses a mild surfactant for fibroin dissolution and is advantageous over other previous reported techniques using chaotropic salts. Fabricated fibroin films are smooth as confirmed by atomic force microscopy. Circular dichroism spectrometry along with Fourier transformed infrared spectroscopy and X-ray diffraction reveal random coil/alpha-helix conformations in regenerated fibroin which transform to beta-sheets, resulting in crystalline structure and protein insolubility through ethanol treatment. Differential scanning calorimetry shows an increase in glass transition (Tg) temperature and enhanced degradation temperature on alcohol treatment. Enhanced cell attachment and viability of AH927 feline fibroblasts were observed on fibroin matrices. Higher mechanical strength along with controllable water stability of regenerated gland fibroin films make non-mulberry Indian tropical tasar silk gland fibroin protein a promising biomaterial for tissue engineering applications.

Biomaterial Scaffold Fabrication Techniques for Potential Tissue Engineering Applications

“…A schematic diagram for scaffold fabrication from silk protein by freeze drying technique is given as an example in figure 1 (Mandal & Kundu, 2008a;2008b;2009b;Kundu et al, 2008 The silk fibroin proteins may be obtained from two different silkworm sources either from the silk gland of non mulberry late 5th instar silkworm larva as an example from Indian tropical tasar silkworm (Antheraea mylitta). It is difficult to obtain sufficient amount of fibroin from cocoon sources of non mulberry (Mandal & Kundu, 2008a;2008b; or from cocoons of mulberry silkworm, Bombyx mori (Altman et al, 2003;Mandal and Kundu, 2009b;Kundu et al, 2008).…”

Potential of inherent RGD containing silk fibroin–poly (Є-caprolactone) nanofibrous matrix for bone tissue engineering

“…Three distinguishable vibration peaks were associated with amide groups in FTIR spectra of non-mulberry silk fibroin protein; 1,650-1,630 cm -1 for amide I (C=O stretching), 1,540-1,520 cm -1 for amide-II (secondary NH bending, due to β-sheet structure), and 1, 270-1,230 cm -1 for amide III (C-N and N-H functionalities) (Fig. 2a) (Mandal and Kundu. 2008b).…”

Non-bioengineered silk gland fibroin micromolded matrices to study cell-surface interactions

“…LiBr and LiSCN for fibroin regeneration. The regenerated protein after dialysis primarily consists of random coils and α-helices which on alcohol treatment transform to β-sheets (Mandal and Kundu 2008c;Asakura and Kuzuhara 1984;Mingzhong et al 1999;Miyazawa and Blout 1961).…”

“…Previously, fibroin from A. mylitta has been isolated and dissolved in a novel way involving an anionic surfactant sodium dodecyl sulfate compared to conventional LiBr method (Bettinger et al 2007;Mandal and Kundu 2008a). Subsequently the protein was analyzed with atomic force microscopy, circular dichroism spectroscopy and fluorescence spectroscopy (Mandal and Kundu 2008c). In the present study, we use an identical protocol of fibroin isolation and fabricate a micro featured matrix with the protein employing the micromolding technique.…”