A major goal of tissue engineering is to generate tissues and organs that mimic the human body’s natural counterparts. A recent discovery of three-dimensional nanoscaffolds by researchers at UAB could lead to new applications for the regeneration of a damaged or diseased body parts in the near future.
Regenerative medicine scientists have been working with biochemically engineered cellular scaffolds for about 20 years, searching for the ideal scaffold to deliver just the right amount of support for new tissue while harmlessly breaking down in the body as new tissue replaces it.
Over the last decade, electro spinning technology has evolved to produce non-woven fibrous scaffolds in a range of sizes; however, the traditional method for electro spinning creates densely packed sheet-like structures that prevent cells from penetrating the nanoscaffolds. The discovery of the three-dimensional electro-spun scaffold opens the door to many possibilities. “This 3-D cotton ball-like electro-spun scaffold consists of an accumulation of nanofibers in a low-density and uncompressed manner,” says Ho-Wook Jun, PhD, assistant professor of biomedical engineering. “The scaffold is made of a synthetic biodegradable polymer that can be used to fabricate any biomaterials into three-dimensional tissues.”
Quantitative analysis shows that cells seeded on the 3D scaffold infiltrated into the scaffold after seven days growth, compared to little penetrating growth for the traditional electro-spun scaffold.
“That growth rate is approximately 40 percent higher, possibly because of the increased space for in-growth within the three-dimensional scaffolds,” Jun says. “Overall, this method assembles a nanofibrous scaffold that is more advantageous for highly porous interconnectivity and demonstrates great potential for tackling current challenges of electro spun scaffolds.”
Bryan Adam Blakeney and Ajay Tambralli, recent graduates of the UAB Department of Biomedical Engineering, conducted the research while they were undergraduate students under Jun’s mentorship. Both are lead authors of the study recently published in the journal Biomaterials.
To achieve the three-dimensional scaffold which they call FLUF – focused, low-density, uncompressed nanofibrous mesh – the researchers used a spherical dish with a slight curvature, similar to that of a home TV satellite, embedded with an array of metal probes during the electro spinning process.
“This allows the nanofibers that constitute the scaffold to intertwine and accumulate without becoming too tightly packed,” says Tambralli, currently a student in the UAB School of Medicine. “High density is the problem with flat, two-dimensional scaffolds.”
Scanning electron microcopy showed that the cotton ball-like scaffold consisted of electro spun nanofibers with a similar diameter but larger pores and a less dense structure compared to the traditional electro spun scaffolds.
“In addition, laser confocal microscopy demonstrated an open porosity and loosely packed structure throughout the depth of the cotton ball scaffold, unlike the superficially porous and tightly packed structure of the traditional ones,” Jun says.
Blakeney compares the discovery process to trying to put a ship in a bottle. He put the material from a syringe into a bottle first to see how it would work. “That didn’t have a good result, but it allowed us to see how it might work,” he says. Blakeney then started trying to create structures using funnels, prongs and other objects in different arrangements. “The bowl structure came from different iterations of the process and evolved into what we have now,” he says.
While they were creating the process, Blakeney says they had no idea of the possible ramifications. “It didn’t seem too amazing at the time, but when we sat back and looked at the broader applications, we realized it is a big deal,” he says.
The patents for the technology have been transferred to start-up company Endomimetics, LLC for further development. “There are huge needs in the medical field for re-engineered tissue, so we want to move forward with different applications as quickly as possible,” Jun says.
Jun likens the revolutionary impact of this technology on the medical field to the effect of the 3D movie Avatar has had on the film industry. “We are in the beginning stages of this discovery, but I can see great potential for this technology in regenerative medicine,” he says.