Module 5
TRENDS IN BIOENGINEERING
3.3 Muscular Systems as Scaffolds:
The use of muscular systems as scaffolds in regenerative medicine is an area of active research and
development. Muscles have the potential to be used as scaffolds for the regeneration of tissues due to
their inherent mechanical properties and ability to support cell growth and tissue formation.
One example of using muscular systems as scaffolds is in the treatment of damaged or diseased
heart tissue. Researchers have developed methods for using muscle cells to create a functional,
threedimensional scaffold that can support the growth of new heart tissue. In this approach, muscle cells
are harvested from the patient and then seeded onto a scaffold, such as a hydrogel or artificial matrix.
The scaffold provides a framework for the cells to grow and differentiate into new heart tissue, which
can help to repair the damaged or diseased tissue.
Another example is in the treatment of skeletal muscle injuries, such as those caused by trauma
or disease. In this case, muscle cells can be harvested and seeded onto a scaffold, which can then be
implanted into the damaged muscle to promote the growth of new, functional tissue.
While the use of muscular systems as scaffolds is still in the experimental stage, it holds great
promise for the treatment of a variety of conditions and represents an area of active research and
development in the field of regenerative medicine.
3.3.1 Architecture
Figure: The Three Connective Tissue Layers: Bundles of muscle fibers, called fascicles,
are covered by the perimysium. Muscle fibers are covered by the endomysium.
Inside each skeletal muscle, muscle fibers are organized into bundles, called fascicles, surrounded
by a middle layer of connective tissue called the perimysium. This fascicular
organization is common in muscles of the limbs; it allows the nervous system to trigger a specific
movement of a muscle by activating a subset of muscle fibers within a fascicle of the muscle. Inside
each fascicle, each muscle fiber is encased in a thin connective tissue layer of collagen and reticular
fibers called the endomysium. The endomysium surrounds the extracellular matrix of the cells and plays
a role in transferring force produced by the muscle fibers to the tendons.
, Inside the muscle fibers, there are tiny structures called myofibrils. Myofibrils are made up of
smaller units called sarcomeres, which are responsible for muscle contraction.
Figure: Representing the sacromere
Sarcomeres contain thin (Actin) and thick filaments (Myosin) that work together to make the
muscle fibers contract. Each muscle fiber is surrounded by a protective layer called endomysium.
Multiple muscle fibers are grouped together into bundles called fascicles. Fascicles are surrounded by
another layer of connective tissue called perimysium.
All the fascicles together make up the entire muscle, which is surrounded by a layer called
epimysium. The muscle also has a special membrane called the sarcolemma, which protects the muscle
fiber. Inside the muscle fiber, there are small tunnels called T-tubules that help transmit signals for
muscle contraction. Muscles work through the coordination of motor units, which consist of a motor
neuron and the muscle fibers it controls. This architecture allows muscles to generate force, move our
bodies, and perform various activities.
3.3.2 Mechanisms
The mechanism of how the muscular system can be used as a scaffold in regenerative medicine
involves the use of muscle cells and a scaffold to support the growth and regeneration of new tissue.
The method of growing muscle tissue using hydrogel or artificial scaffold is explained below:
, Figure: Representing the muscle tissue growth using hydrogel or artificial scaffold
Figure: Representing the formation of polymer based scaffold and cell culture The basic
steps in this process are as follows:
• Harvesting of muscle cells: Muscle cells are typically obtained from the patient and then isolated
and expanded in culture.
• Seeding onto scaffold: The muscle cells are then seeded onto a scaffold, such as a hydrogel or
artificial matrix. The scaffold provides a framework for the cells to grow and differentiate into
new tissue.
, • Cell differentiation and tissue formation: Once the cells are seeded onto the scaffold, they
undergo differentiation, in which they change into specific cell types, such as muscle cells or
heart cells. The cells also begin to organize and form new tissue, such as heart tissue or skeletal
muscle tissue.
• Implantation into patient: The scaffold and cells are then implanted into the patient to promote
the growth of new, functional tissue.
3.3.3 Muscle Cells as Scaffold
Muscle cells can be used as a scaffold for tissue generation by removing the living cells from the
muscle tissue, leaving behind the structure known as the extracellular matrix (ECM). This decellularized
muscle scaffold provides a framework that can guide and support the growth of new tissues.
Figure: Representing muscle scaffold for tissue growth The
Process
• Harvesting muscle tissue: A small sample of muscle tissue is taken, typically from a donor or
an animal model.
• Cell removal: The living cells within the muscle tissue are removed using a process called
decellularization. This involves treating the tissue with specific chemical solutions or enzymes
that break down and wash away the cellular components, while preserving
the ECM.
• ECM scaffold: The remaining ECM, which forms the structure of the muscle, is now a scaffold.
It consists of proteins, such as collagen and elastin, and other molecules that provide support
and signals for tissue growth.
• Seeding cells: The decellularized muscle scaffold is then seeded with desired cells. These can
be stem cells or specialized cells relevant to the type of tissue being regenerated. The cells are
introduced onto the scaffold, allowing them to attach and populate the structure.
• Tissue growth: Over time, the seeded cells proliferate and differentiate, meaning they multiply
and transform into specific cell types required for the desired tissue. The ECM scaffold guides
the cells' growth, providing physical support, and biochemical cues to influence their behavior.
TRENDS IN BIOENGINEERING
3.3 Muscular Systems as Scaffolds:
The use of muscular systems as scaffolds in regenerative medicine is an area of active research and
development. Muscles have the potential to be used as scaffolds for the regeneration of tissues due to
their inherent mechanical properties and ability to support cell growth and tissue formation.
One example of using muscular systems as scaffolds is in the treatment of damaged or diseased
heart tissue. Researchers have developed methods for using muscle cells to create a functional,
threedimensional scaffold that can support the growth of new heart tissue. In this approach, muscle cells
are harvested from the patient and then seeded onto a scaffold, such as a hydrogel or artificial matrix.
The scaffold provides a framework for the cells to grow and differentiate into new heart tissue, which
can help to repair the damaged or diseased tissue.
Another example is in the treatment of skeletal muscle injuries, such as those caused by trauma
or disease. In this case, muscle cells can be harvested and seeded onto a scaffold, which can then be
implanted into the damaged muscle to promote the growth of new, functional tissue.
While the use of muscular systems as scaffolds is still in the experimental stage, it holds great
promise for the treatment of a variety of conditions and represents an area of active research and
development in the field of regenerative medicine.
3.3.1 Architecture
Figure: The Three Connective Tissue Layers: Bundles of muscle fibers, called fascicles,
are covered by the perimysium. Muscle fibers are covered by the endomysium.
Inside each skeletal muscle, muscle fibers are organized into bundles, called fascicles, surrounded
by a middle layer of connective tissue called the perimysium. This fascicular
organization is common in muscles of the limbs; it allows the nervous system to trigger a specific
movement of a muscle by activating a subset of muscle fibers within a fascicle of the muscle. Inside
each fascicle, each muscle fiber is encased in a thin connective tissue layer of collagen and reticular
fibers called the endomysium. The endomysium surrounds the extracellular matrix of the cells and plays
a role in transferring force produced by the muscle fibers to the tendons.
, Inside the muscle fibers, there are tiny structures called myofibrils. Myofibrils are made up of
smaller units called sarcomeres, which are responsible for muscle contraction.
Figure: Representing the sacromere
Sarcomeres contain thin (Actin) and thick filaments (Myosin) that work together to make the
muscle fibers contract. Each muscle fiber is surrounded by a protective layer called endomysium.
Multiple muscle fibers are grouped together into bundles called fascicles. Fascicles are surrounded by
another layer of connective tissue called perimysium.
All the fascicles together make up the entire muscle, which is surrounded by a layer called
epimysium. The muscle also has a special membrane called the sarcolemma, which protects the muscle
fiber. Inside the muscle fiber, there are small tunnels called T-tubules that help transmit signals for
muscle contraction. Muscles work through the coordination of motor units, which consist of a motor
neuron and the muscle fibers it controls. This architecture allows muscles to generate force, move our
bodies, and perform various activities.
3.3.2 Mechanisms
The mechanism of how the muscular system can be used as a scaffold in regenerative medicine
involves the use of muscle cells and a scaffold to support the growth and regeneration of new tissue.
The method of growing muscle tissue using hydrogel or artificial scaffold is explained below:
, Figure: Representing the muscle tissue growth using hydrogel or artificial scaffold
Figure: Representing the formation of polymer based scaffold and cell culture The basic
steps in this process are as follows:
• Harvesting of muscle cells: Muscle cells are typically obtained from the patient and then isolated
and expanded in culture.
• Seeding onto scaffold: The muscle cells are then seeded onto a scaffold, such as a hydrogel or
artificial matrix. The scaffold provides a framework for the cells to grow and differentiate into
new tissue.
, • Cell differentiation and tissue formation: Once the cells are seeded onto the scaffold, they
undergo differentiation, in which they change into specific cell types, such as muscle cells or
heart cells. The cells also begin to organize and form new tissue, such as heart tissue or skeletal
muscle tissue.
• Implantation into patient: The scaffold and cells are then implanted into the patient to promote
the growth of new, functional tissue.
3.3.3 Muscle Cells as Scaffold
Muscle cells can be used as a scaffold for tissue generation by removing the living cells from the
muscle tissue, leaving behind the structure known as the extracellular matrix (ECM). This decellularized
muscle scaffold provides a framework that can guide and support the growth of new tissues.
Figure: Representing muscle scaffold for tissue growth The
Process
• Harvesting muscle tissue: A small sample of muscle tissue is taken, typically from a donor or
an animal model.
• Cell removal: The living cells within the muscle tissue are removed using a process called
decellularization. This involves treating the tissue with specific chemical solutions or enzymes
that break down and wash away the cellular components, while preserving
the ECM.
• ECM scaffold: The remaining ECM, which forms the structure of the muscle, is now a scaffold.
It consists of proteins, such as collagen and elastin, and other molecules that provide support
and signals for tissue growth.
• Seeding cells: The decellularized muscle scaffold is then seeded with desired cells. These can
be stem cells or specialized cells relevant to the type of tissue being regenerated. The cells are
introduced onto the scaffold, allowing them to attach and populate the structure.
• Tissue growth: Over time, the seeded cells proliferate and differentiate, meaning they multiply
and transform into specific cell types required for the desired tissue. The ECM scaffold guides
the cells' growth, providing physical support, and biochemical cues to influence their behavior.
