Surface, cross-sectional optical/SEM images showing the uniaxially aligned...
Surface, cross-sectional optical/SEM images showing the uniaxially aligned surface patterns and microchannels within the struts of the fabricated collagen scaffolds. A schematic showing the osteogenesis and angiogenesis of the fabrication of mineralized, microchanneled collagen scaffold.
Source: Hanjun Hwangbo, Hyeongjin Lee

Using 4D printing to enable spinal fusion

4D printing helps create a biomimetic microchannel scaffold made of collagen and hydroxyapatite.

Spinal fusion is frequently performed to restore spinal stability in patients with spinal diseases, such as spinal stenosis, vertebral fractures, progressive deformities, and instability. In the past two decades, there has been a marked increase in the number of people over 65 years in age who have needed spinal fusion surgery.

While autogenous bone grafts have long been considered the reference standard for spinal fusion, painful pseudoarthrosis remains a leading cause of poor clinical outcomes. Many researchers have consequently focused on trying to create a biomimetic scaffold that induces vascularization to enable bone tissue regeneration and spinal fusion.

In Applied Physics Reviews, researchers from Sungkyunkwan University in South Korea present a solution to address the challenge of fabrication of a biomimetic scaffold. The team designed a microchannel scaffold made of a collagen and hydroxyapitite combination, with each strut consisting of micrometer-scaled microchannels. The microchannels have induced growth of blood vessels in a mouse model.

"Since the fabrication of biomimetic scaffold is a challenging issue, the innovation of this study lies in adding extra hierarchy to the structure in the form of microchannels," said author Geun Hyung Kim. "This was achieved through a 4D printing strategy, where one-way shape morphing is used."

The researchers printed immiscible polymer blends that act as a double negative template in order to fabricate the the biomimetic collagen/hydroxyapatite hierarchical scaffold. They followed that by one-way shape morphing (4D printing) and coating processes.

Collagen is known as a hydrophilic material, and numerous in vivo studies have suggested it possesses excellent cellular activities. In the case of the microchanneled collagen/hydroxyapatite scaffold, the researchers noted significantly higher water-absorbing capability, compared to a conventional collagen scaffold, as a result of the capillary pressure supplied by the microchannels. Consequently, the in vivo studies have suggested excellent infiltration of cells into microchannels.

Going forward, the researchers will investigate enhancing the mechanical properties of the scaffold. Furthermore, controlling the mechanical properties of the scaffold would enable versatile applications of the microchanneled collagen/hydroxyapatite scaffold. "I believe that the designed scaffold can have multiple applications with tubular structures such as muscle, tendon, and nerve," said Kim.

Skeletal muscle is a hierarchical organization where the muscle fibers are encapsulated in microchannels known as endomysium. Therefore, the designed scaffold could act as endomysium to enable the infiltration of muscle fibers into the channels.

Subscribe to our newsletter

Related articles

4D printing the world’s smallest stent

4D printing the world’s smallest stent

Researchers have developed a new method for producing malleable microstructures – for instance, vascular stents that are 40 times smaller than previously possible.

Researchers use bioprinting to create nose cartilage

Researchers use bioprinting to create nose cartilage

Researchers have used 3D bioprinting technology to create custom-shaped cartilage. They aim to make it easier for surgeons to safely restore the features of skin cancer patients living with nasal cartilage defects after surgery.

3D biocomposites can repair large bone defects

3D biocomposites can repair large bone defects

Loosening hip implants can cause major damage to the bone and a simple replacement won’t suffice to carry the load during movements. Researchers have turned to bioprinting to solve this problem.

Hydrogel can repair tears in human tissue

Hydrogel can repair tears in human tissue

Scientists have developed an injectable gel that can attach to various kinds of soft internal tissues and repair tears resulting from an accident or trauma.

A promising future for soft bioelectronic interfaces

A promising future for soft bioelectronic interfaces

Researchers have demonstrated MRI compatibility in their soft electrode arrays – a crucial step in translation to the clinic.

Antibiotics embedded in 3D printed implants used to regenerate damaged bone

Antibiotics embedded in 3D printed implants used to regenerate damaged bone

Researchers have fabricated 3D scaffold implants containing antibiotics at high temperatures. These scaffolds support bone regeneration and manage the bone infections.

Adaptive microelectronics reshape independently

Adaptive microelectronics reshape independently

Nanoscientists have developed adaptive microelectronics that can move independently according to sensor data and align themselves specifically for activities - possible applications in biomedicine and bioneural interfacing.

Advanced tech enables simulated sinus surgery

Advanced tech enables simulated sinus surgery

The world’s first international online training session utilizing advanced 3D sinus models and a telemedicine system has taken place.

Shape-changing 4D materials hold promise for bioengineering

Shape-changing 4D materials hold promise for bioengineering

New hydrogel-based materials that can change shape in response to psychological stimuli, such as water, could be the next generation of materials used to bioengineer tissues and organs.

Popular articles

Subscribe to Newsletter