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Posts Tagged ‘tissue constructs’

UPDATE 

6/7/2020

3D PRINT CELLULOSE-BASED HYDROGEL WITH PROGRAMMABLE DEFORMATION

Scientists at University of Stuttgart, University of Virgnia and Koc Universityhave 3D printed multimaterial parts with multidirectional stiffness gradients. By mixing their expertise in materials engineering and digital processing, scientists create a series of sets of cellulose-based filaments with modifying mechanical and rheological properties, despite having similar compositions. The materials were then used in conjunction with each other to program specific deformation profiles into complex parts.

Functionally graded materials (FGMs) have a gradually changing composition or structure and can be designed to create a precise stiffness profile in each part was then generated. When printed, the samples could be deformed in distinctive profiles due the alteration in stiffness across the geometry of the parts. Eventually, scientists had ‘programmed’ a set of desired deformation geometries.

SOURCE

https://advances.sciencemag.org/content/6/8/eaay0929/tab-article-info

 

Three-dimensional printed microfibers used to reinforce hydrogels

Reporter: Irina Robu, PhD

The field of tissue engineering has continued to evolve with the intention to restore, replace and regenerate loss and damaged tissues. Engineered tissues have been able to help millions of people which why their development and design is important. The tree components that are needed for this are cells, scaffold and bioactive factors. 

The scaffold is responsible for providing the structure and support needed to provide tissue development but they differ in composition, design, material properties, structure properties etc. In the spite of everything,  the concept of a scaffold is to mimic the function of the native extracellular matrix by creating similar architectural, biological and mechanical features.

One classic material that is used for tissue engineering are hydrogels, which are designed to provide a hydrated 3D environment of the cells which act as cell carriers. But, hydrogels are unable to provide the needed mechanical properties needed to form extracellular matrix.

Taking the account the limitation, scientists from Medical Center at Utrecht University created a 3D dimensional microfiber network through melt electrospinning to reinforce hydrogel architecture, in order to provide mechanical and biological stable environment for engineered constructs. They took into account that they hydrogel mechanical properties should match those of the target tissue to promote enhanced performance. 

Researchers in the past have tried to mimic  the architecture of native tissues including reinforced nanofibers, woven scaffolds, non-woven scaffolds and microfibers. The typical manufacturing technique used is electrospinning which is advantageous because it creates a more accurate structural mimic of the native tissue extracellular matrix. 

In the study published by researchers at University of Utrecht Medical Center, use melt electrospinning. This electrospinning assembles the fibers layer by layer, supplying regulated control over assembly architecture. The researchers aimed to create a support for gelatin methacrylamide hydrogels with high porosity fiber scaffolds made of poly(ε-caprolactone) (PCL). The composite was created by infusing and crosslinking methacrylamide hydrogels within the PCL scaffolds. To stimulate the level of hydrogel reinforcement, a mathematical model was developed using the scaffold parameters. 

The study showed that the reinforced hydrogel stiffness was identical to that of articular cartilage as it increased up to 54-fold compared to hydrogels or microfiber scaffolds alone. The microfiber network can be used by various types of hydrogels which indicates that  they can offer mechanically and biologically favorable environments for various types of engineered tissues.

This current development in the field of tissue engineering will allow for the creation and use of resistant and effectual hydrogels to treat tissue loss or damage. The organized fibrous PCL scaffolds within the hydrogel allow for a healthy and diversified cell culture environment, because the hydrogel degrades over a few months which allows for new tissue to integrate into the scaffold. The PCL scaffold will in turn disintegrate within years, acting as a reinforcing network that will develop functional tissue. This reinforced hydrogel represents a step towards creating biomechanical functional tissue constructs and hopefully, more research will someday lead to the creation of the ideal, modify according to individual specifications engineered tissue replacement.

Source

http://www.nature.com/ncomms/2015/150428/ncomms7933/full/ncomms7933.html#access

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