18.7 Types of Scaffolds for CTE from Natural
Biomaterials
Generally, scaffolds are designed to be fibrous or porous in nature. Fibrous scaffolds
mimic the nanoscale structure of the native ECM and their topology and porosity
can be designed to modify the cell behaviour. They contain a large
surface-to-volume ratio, high permeability and interconnecting pore structure,
which allow efficient infiltration and proliferation of cells. On the other hand,
porous scaffolds support host cell infiltration and vascularization, and provide a
large surface area for cell adhesion, differentiation and proliferation, thus making
them advantageous for growing functional 3D tissues.
18.7.1 Fibrous Scaffolds
Fibrous scaffolds are generally created by electrospinning of polymer solutions. The
process of electrospinning involves dispensing of a biopolymer out of a syringe
needle and its exposure through a charged voltage gradient between the needle and
a collector. The diameter, density, and alignment of electrospun fibers can be
controlled by optimizing the viscosity and flow-rate of the polymer solution, the
voltage gradient, and the topography of the collector (Zhou et al. 2019). Natural and
hybrid biomaterials have been used for electrospinning (Pushp et al. 2017). In
addition, composite materials comprised of layers of different polymers such as
PLGA/gelatine can also be created by electrospinning for developing cardiac patches (Prabhakaran et al. 2011). Bio-functionalized fibrous scaffolds can also be
electrospun by adding functional materials to the polymers before or after electrospinning. Kai et al. incorporated Polypyrrole (PPy) to PCL/gelatine solution
before electrospinning to impart electroconductivity to the nanofibers.
Various modifications for creating specialized nanofibrous scaffolds have also
been reported. Ravichandran et al. (2013b) fabricated core/shell fibers by co-axial
electrospinning, with PGS as core material and fibrinogen as shell material. Among
various modifications, the creation of aligned nanofibrous scaffolds is considered as
the most important for CTE as they structurally mimic oriented ECM of the heart
(Parrag et al. 2012). Gelatin-coated aligned PCL nanofibrous scaffold greatly promoted cell attachment and alignment because of biological components and ordered
topography of scaffolds (Kai et al. 2011). In our study, we observed that PCL
aligned nanofibers, coated with collagen I, promoted cell attachment and proliferation of MSCs cells. The MSCs attached, penetrated, and spread well on the surface
of aligned nanofibrous scaffold than random nanofiber (Pushp et al. 2019). Similar
results were also observed with iPSCs (Fig. 18.2). However, the biggest limitation
of electrospinning is the inability to form thick scaffolds due to low fiber packaging
density and entrapment of cells (Venkataraman et al. 2018).
18 Cardiac Tissue Engineering: A Role for Natural Biomaterials
631
Biomaterials
Generally, scaffolds are designed to be fibrous or porous in nature. Fibrous scaffolds
mimic the nanoscale structure of the native ECM and their topology and porosity
can be designed to modify the cell behaviour. They contain a large
surface-to-volume ratio, high permeability and interconnecting pore structure,
which allow efficient infiltration and proliferation of cells. On the other hand,
porous scaffolds support host cell infiltration and vascularization, and provide a
large surface area for cell adhesion, differentiation and proliferation, thus making
them advantageous for growing functional 3D tissues.
18.7.1 Fibrous Scaffolds
Fibrous scaffolds are generally created by electrospinning of polymer solutions. The
process of electrospinning involves dispensing of a biopolymer out of a syringe
needle and its exposure through a charged voltage gradient between the needle and
a collector. The diameter, density, and alignment of electrospun fibers can be
controlled by optimizing the viscosity and flow-rate of the polymer solution, the
voltage gradient, and the topography of the collector (Zhou et al. 2019). Natural and
hybrid biomaterials have been used for electrospinning (Pushp et al. 2017). In
addition, composite materials comprised of layers of different polymers such as
PLGA/gelatine can also be created by electrospinning for developing cardiac patches (Prabhakaran et al. 2011). Bio-functionalized fibrous scaffolds can also be
electrospun by adding functional materials to the polymers before or after electrospinning. Kai et al. incorporated Polypyrrole (PPy) to PCL/gelatine solution
before electrospinning to impart electroconductivity to the nanofibers.
Various modifications for creating specialized nanofibrous scaffolds have also
been reported. Ravichandran et al. (2013b) fabricated core/shell fibers by co-axial
electrospinning, with PGS as core material and fibrinogen as shell material. Among
various modifications, the creation of aligned nanofibrous scaffolds is considered as
the most important for CTE as they structurally mimic oriented ECM of the heart
(Parrag et al. 2012). Gelatin-coated aligned PCL nanofibrous scaffold greatly promoted cell attachment and alignment because of biological components and ordered
topography of scaffolds (Kai et al. 2011). In our study, we observed that PCL
aligned nanofibers, coated with collagen I, promoted cell attachment and proliferation of MSCs cells. The MSCs attached, penetrated, and spread well on the surface
of aligned nanofibrous scaffold than random nanofiber (Pushp et al. 2019). Similar
results were also observed with iPSCs (Fig. 18.2). However, the biggest limitation
of electrospinning is the inability to form thick scaffolds due to low fiber packaging
density and entrapment of cells (Venkataraman et al. 2018).
18 Cardiac Tissue Engineering: A Role for Natural Biomaterials
631