mori as well as non-mulberry Antheraea mylitta has been used for CTE (Patra et al.
2012). It is composed of heavy and light chain of core proteins called fibroins,
which is coated by another protein called sericin—a glue, which help to bind silk
fibroins together due to its sticky nature. It is a natural biopolymer with excellent
mechanical strength, extensibility, elasticity and strain hardening. The strength-todensity ratio of silk is much higher than that of steel. The mechanical properties of
silk, which include extreme elasticity (5–17 GPa), toughness, tensile strength (500–
900 MPa), and compression resistance, depends on the hydrophobic region composed of repetitive amino acid sequences. Silk also has small diameter and occur as
aligned fibers which increases the surface area to volume ratio. Properties such as
slow degradation, high tensile strength, good oxygen and water permeability support better cell adhesion and growth, which made it one of the demanding
biopolymer for CTE. In fact, scaffolds prepared from silk fibroin not only induced
alignment of the cells but also helped in synthesis of titin, a protein critical to
sarcomere assembly that provide elasticity to the muscles (Cutts et al. 2015).
The main limitation in the use of silk is its hypersensitivity reactions and adverse
immunological effects due to non-mammalian origin. The immune response can be
improved by removing sericin through a process called degumming (Altman et al.
2003). After degumming, the silk used to dissolve in appropriate solvent such as
formic acid, calcium nitrate, calcium chloride, ionic liquids, hexafluoroisopropanol,
lithium bromide (Kluge et al. 2008) to form scaffold. Silk fibrous has been used as
films, hydrogel, 3-D macro or micro capsules, porous scaffolds, and electro-spun
and wet-spun fibers. The porous silk-based matrix can be formed by salt leaching,
gas foaming and freeze drying whereas fibrous scaffolds can be formed by electrospinning or microfluidic approaches. The porosity and mechanical properties of
matrix formed can be controlled by concentration of silk fibroin and particle size of
salt. Several authors have reported efficient seeding of CM into silk fibroin scaffolds
to form contractile patches (Patra et al. 2012). Rahimi et al. developed a
thermo-sensitive conductive hydrogel with a highly porous network of interconnected pores by incorporating nanoscale electro-conductive gold nanoparticles
(Au-NPs) into chitosan hydrogels (Rahimi et al. 2014). Silk fibroin exhibited
similar properties of cell attachment as fibronectin, a component of the natural
matrix for CM, probably due to its RGD domains.
Composite of silk fibroin with chitosan or hyaluronic acid has also been used to
generate cardiac patch from seeded MSCs, which promoted cell growth and cardiomyogenic differentiation (Yang et al. 2010) and, upon transplantation into rat
heart model of MI, improved cardiac repair (Chi et al. 2013). Silk fibroin has also
been used as a coating material for surface modification of synthetic biopolymers.
Liang et al. immobilized silk fibroin on poly (ethylene terephthalate) (PET) film via
plasma pre-treatment followed by dip coating, which gave high surface roughness
and promoted MSCs culture (Liang et al. 2013).
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P. Pushp and M. K. Gupta
2012). It is composed of heavy and light chain of core proteins called fibroins,
which is coated by another protein called sericin—a glue, which help to bind silk
fibroins together due to its sticky nature. It is a natural biopolymer with excellent
mechanical strength, extensibility, elasticity and strain hardening. The strength-todensity ratio of silk is much higher than that of steel. The mechanical properties of
silk, which include extreme elasticity (5–17 GPa), toughness, tensile strength (500–
900 MPa), and compression resistance, depends on the hydrophobic region composed of repetitive amino acid sequences. Silk also has small diameter and occur as
aligned fibers which increases the surface area to volume ratio. Properties such as
slow degradation, high tensile strength, good oxygen and water permeability support better cell adhesion and growth, which made it one of the demanding
biopolymer for CTE. In fact, scaffolds prepared from silk fibroin not only induced
alignment of the cells but also helped in synthesis of titin, a protein critical to
sarcomere assembly that provide elasticity to the muscles (Cutts et al. 2015).
The main limitation in the use of silk is its hypersensitivity reactions and adverse
immunological effects due to non-mammalian origin. The immune response can be
improved by removing sericin through a process called degumming (Altman et al.
2003). After degumming, the silk used to dissolve in appropriate solvent such as
formic acid, calcium nitrate, calcium chloride, ionic liquids, hexafluoroisopropanol,
lithium bromide (Kluge et al. 2008) to form scaffold. Silk fibrous has been used as
films, hydrogel, 3-D macro or micro capsules, porous scaffolds, and electro-spun
and wet-spun fibers. The porous silk-based matrix can be formed by salt leaching,
gas foaming and freeze drying whereas fibrous scaffolds can be formed by electrospinning or microfluidic approaches. The porosity and mechanical properties of
matrix formed can be controlled by concentration of silk fibroin and particle size of
salt. Several authors have reported efficient seeding of CM into silk fibroin scaffolds
to form contractile patches (Patra et al. 2012). Rahimi et al. developed a
thermo-sensitive conductive hydrogel with a highly porous network of interconnected pores by incorporating nanoscale electro-conductive gold nanoparticles
(Au-NPs) into chitosan hydrogels (Rahimi et al. 2014). Silk fibroin exhibited
similar properties of cell attachment as fibronectin, a component of the natural
matrix for CM, probably due to its RGD domains.
Composite of silk fibroin with chitosan or hyaluronic acid has also been used to
generate cardiac patch from seeded MSCs, which promoted cell growth and cardiomyogenic differentiation (Yang et al. 2010) and, upon transplantation into rat
heart model of MI, improved cardiac repair (Chi et al. 2013). Silk fibroin has also
been used as a coating material for surface modification of synthetic biopolymers.
Liang et al. immobilized silk fibroin on poly (ethylene terephthalate) (PET) film via
plasma pre-treatment followed by dip coating, which gave high surface roughness
and promoted MSCs culture (Liang et al. 2013).
626
P. Pushp and M. K. Gupta