Sprayable bandages with super-wound healing capabilities. Dialysis components small enough to be worn by the patient. These are just two of the life science product concepts using nanofibers (“NF”) which have captured the attention of the popular scientific press – and this doesn’t include many of the more near term uses of nanofibers in life science applications such as tissue scaffolds, improved performance wound care bandages and higher performance facemasks and garments for physicians and other care providers.
The number of applications that can use NF in life sciences is growing quickly. With a century of scientific research behind it, electrospun nanofibers are actually well prepared to grow with demand – the industrial infrastructure already exists such that industry can keep pace with the needs of the medical industry. As it grows, it looks increasingly like the significance of nanofibers will be on par with two previous significant technological advancements introduced to the world of medicine after having been pioneered by the textile supply chain.
Gift 1: Dyes and stains
With Leeuwenhoek’s improvements to the microscope, new challenges emerged as scientists began to explore the newly revealed structures. It was hard to tell what was what. Fortunately, scientists were able to pull from the existing textile toolkit and evaluate the growing library of dyes.
“I have therefore published the method, although I am aware that as yet it is very defective and imperfect; but it is hoped that also in the hands of other investigators it will turn out to be useful.” Hans Christian Gram (1853-1938)
Gram’s original goal was to determine whether or not lungs were infected – it would evolve into a way to separate different strains of bacteria. Dyes were a well known art and an early driver for advanced forms of chemical synthesis. Different dyes had a wide variety of chemical structures, giving the early microscopists many potential options. Once Gram had introduced the concept, the art would flourish and eventually lead to antibiotics, where sulfa would then emerge as the second gift from textiles to medicine.
Gift 2: Antibioitcs & sulfa
When Gerhard Domagk and his colleagues at Bayer first determined the potential medical benefits of antibiotics in fighting disease and began development of what became Prontosil, the first Sulfa drug in 1932, it was initially believed that the sulfa had to be tied to a dye. Eventually, it was determined that basic Sulfa was sufficient. Sulfa was widely available, used as part of textile processing and had expired patents. The process had been originally developed in 1908 by Austrian Chemist Paul Gelmo and patented by Bayer – providing the recipe to the public domain and providing them with an expired patent for defense.
The medical impact was huge, anyone could make sulfa and the manufacturing process was well established. For these first two gifts there are several similar traits; (i) significant medical impact, (ii) a large library of components already developed, (iii) there was an existing industrial supply chain, (iv) there was little barrier to competition. The gift made a difference, it came in many, trust-worthy flavors, and anyone could get it. Electrospun NF share many of these characteristics. So does the third gift – the nonwoven.
Gift 3: Nonwovens
Walk into a modern hospital room and you are surrounded by nonwovens. The care-givers, physicians and nurses, are covered in nonwoven garments to protect themselves and the patient. The filters, both air, blood and other liquid that keep a patient alive are made possible with nonwoven layers. The MERV 16 filters commonly used are also nonwovens.
Nonwovens emerged with significant investment from the polymer and fiber industries and they found a home throughout the hospital. They were; (i) low cost, (ii) available in many flavors, (iii) disposable and recyclable if needed, and (iv) robust and dependable. Again, all characteristics which made their adoption inevitable. Their impact is more along the line of the dyes, rather than the medical revolution caused by sulfa and the following antibiotics, but their impact is no less important.
Gift 4: Nanofibers?
NF adoption in life science applications is growing. Solution electrospinning does not damage live cells and works with many polymers which have widely characterized behavior in the human body. The webs formed have very uniform, and very fine, pores. This allows small things to flow and stop bigger things – further the pore size has demonstrated its attractiveness as a bed for growing cells. The NF web can be coated with other known components used in biology –receptor proteins used in chromatography or even antibiotics delivered in specific doses.
Individually this list of performance criteria is significant – in combination the performance that will be enabled is over whelming. There is over a 100 years of history in electrospinning – it is a well characterized process with known performance and theoretical underpinnings.
Industrial nanofiber production installations are common and lab scale equipment can be purchased easily at market-based prices. There is considerable literature in academia, intellectual property and industry about what methods are practiced, what recipes are used and their commercial and performance implications.
It is not yet a given that nanofibers are the clear fourth gift from textiles to medicine, but many of the signs are there.
 This is best covered in Hager’s excellent book, The Demon Under the Microscope.