Manufacturing human tissue from textiles
Until we can figure out our lack of regenerating our bodies, or can convince more people to donate organs, we are at mercy of either luck or technology. Bio 3-D printing offers hope that we can print personalized organs as need and rejection free. But the technology relies almost solely with tissue engineers, there job is to find processes using novel bio-materials seeded with stem cells to grow and replace missing tissues.
The idea behind tissue engineering is like trying to build a home, you need a frame work or a “scaffold” to hold things in place. In the case of tissue engineering these scaffolds hold stem cells eventually degrade, leaving natural tissue in its place.
Great idea, but the catch is ramping up the production of scaffolding needed for the job — and if you look at how many people are on the transplant list for any given organ, that is a big job.
Researchers have been recently testing new methods to make the process of tissue engineering more cost effective and producible in larger quantities. Tissues that are not just for growing organs to transplant.
We are talking tissues that could help patients suffering from wounds caused by diabetes and circulation disorders, patients in need of cartilage or bone repair and to women who have had mastectomies by replacing their breast tissue, or burn victims.
In typical tissue engineering approaches that use fibers as scaffolds, non-woven materials are often bonded together using an electrostatic field. This process, called electrospinning, creates the scaffolds needed to attach to stem cells; however, large-scale production is not cost-effective.
“Electrospinning produces weak fibers, scaffolds that are not consistent and have pores that are too small,” Elizabeth Loboa, dean of the MU College of Engineering, said.
“We can run our system for hours and create about a ten-inch diameter of scaffold material. Therefore, we sought to test methods that could standardize the process.”
“The goal of ‘scaling up’ is to produce hundreds of meters of material that look the same, have the same properties and can be used in clinical settings.”
“So, we investigated the processes that create textiles, such as clothing and window furnishings like drapery, to scale up the manufacturing process.”
The group published a pair of papers using three common textile creation methods — meltblowing, spunbonding and carding — to determine if these methods would create the materials needed to mimic native tissue.
For those who are not a fan of links, meltblowing is a technique during which non-woven materials are created using a molten polymer to create continuous fibers. Spunbond materials are made much the same way but the fibers are drawn into a web while in a solid state instead of a molten one. Carding involves the separation of fibers through the use of rollers, forming the web needed to hold stem cells in place.
The team used these techniques to create polylactic acid (PLA) scaffolds — don’t panic, it is a Food and Drug Administration-approved material used as collagen fillers — seeded with human stem cells. They then spent three weeks studying whether the stem cells remained healthy and if they began to differentiate into fat and bone pathways, which is the goal of using stem cells in a clinical setting when new bone and/or new fat tissue is needed at a defect site.
Turns out that the answer might have been in front of us all a long because the results showed that the three textile manufacturing methods proved as viable if not more so than electrospinning.
“These alternative methods are more cost-effective than electrospinning,” Loboa said.
“A small sample of electrospun material could cost between $2 to $5. The cost for the three manufacturing methods is between $.30 to $3.00; these methods proved to be effective and efficient.”
“Next steps include testing how the different scaffolds created in the three methods perform once implanted in animals.”
While not quite as interesting as regenerating tissues yourself, it is exciting to think that we could have a solution to our lack of spare parts soon.
Tuin, S., Pourdeyhimi, B., & Loboa, E. (2016). Creating tissues from textiles: scalable nonwoven manufacturing techniques for fabrication of tissue engineering scaffolds Biomedical Materials, 11 (1) DOI: 10.1088/1748-6041/11/1/015017