Bioink refers to substances made of living cells that can be used for 3D printing of complex tissue models. Bioinks are materials that mimic an extracellular matrix environment to support the adhesion, proliferation, and differentiation of living cells. Bioinks distinguish themselves from traditional biomaterials such as hydrogels, polymer networks, and foam scaffolds due to their ability to be deposited as filaments during an additive manufacturing process. They can be alginate-based, gelatin based, pluronics, and decellularized ECM-based.
Alginate is a naturally derived biopolymer from the cell wall of brown algae that has been widely used as a biomaterial. Alginates are particularly suitable for bioprinting due to their mild cross-linking conditions via incorporation of divalent ions such as calcium. These materials have been adopted as bioinks through increasing their viscosity. Additionally, these alginate-based bioinks can be blended with other materials such as nanocellulose for application in tissues such as cartilage.
Gelatin has been widely utilized as a biomaterial for engineered tissues. The formation of gelatin scaffolds is dictated by the physical chain entanglements of the material which forms a gel at low temperatures. However, at physiological temperatures (body temperature), the viscosity of gelatin drops significantly. Methacrylation of gelatin is a common approach for the fabrication of gelatin scaffolds that can be printed and maintain shape fidelity at physiological temperature. Methacrylation is important for restorative material properties and bioengineering.
Decellularized extracellular matrix based bioinks can be derived from almost any mammalian tissue. However, most organs such as heart, muscle, cartilage, bone, and fat are decellularized, lyophilized, and pulverized, to create a soluble matrix that can then be formed into gels. These bioinks have advantages over other materials due to their derivation from mature tissue. These materials consist of a complex mixture of decellularized extracellular matrix and proteins specific to their tissue origin. Therefore, dECM-derived bioinks are particularly tailored to provide tissue-specific cues to cells. Often these bioinks are cross-linked through thermal gelation or chemical cross-linking such as through the use of riboflavin.
Pluronics have been utilized in printing application due to their unique gelation properties. Below physiological temperatures, the pluronics exhibit low viscosity. However, at physiological temperatures, the pluronics form a gel. A more permanent pluronic-based network can be formed through the modification of the pluronic chain with acrylate groups that may be chemically cross-linked.
So, I have done my obligatory duty of informing you with new material. However, I am not here to only be a scribe with no life. Let us get a little more excited about this article. Is it not wild to think that most of the materials used in bioinks are readily synthesizable? I could order all of this and make some in my own home if I wanted. I also think the material properties discussed are so vast and interesting. Just having a little bit of organic chemistry as well as biochemistry knowledge leads a user to fully enjoy and soak in the importance of biomaterials. I believe it is necessary for me to at some point show some live demonstrations of synthesis with these materials. Talking gets boring after a while, but practical work gets exciting.
You May Also Like
What is Metrology Part 15: Inverse Filtering
This is an article on the essence of Inverse Filtering. Within this image processing method there are two distinct methods to deblur images.
What is Metrology Part 14: Image Restoration
This is an article detailing the depth of information and and knowledge within image restoration. Be prepared to take a brief trip on the extent of this technology and how it can be utilized.
What is Metrology Part 13: Object Recognition
This is an article focused on object recognition and how humans are doing such compared to computer systems. There is an attention to detail that humans have more then robots currently.
What is Metrology Part 12: 3D Reconstruction
In this article we are taking a closer look at 3D reconstruction. It is one of the many interesting fields to study under the lens of metrology and computer vision.
View our broad assortment of in house and third party products.