Nonwovens For Medical Applications


N
onwoven textiles play a significant role in the medical sector. The product range
includes surgical gowns, masks and other wearable products; surgical drapes, pads; dressings;
filtration materials; and implantable textiles such as tissue scaffolds for rebuilding internal
organs, among other products.

By far, most nonwoven products used outside the body are disposable, single-use articles that
have the advantage of not requiring sterilization or cleaning for reuse. However, there are some
that can be reused to provide the required function over a limited period of time.

In North America, disposable nonwoven medical apparel products alone represent a market
totaling nearly $1.46 billion, according to the Association of the Nonwoven Fabrics Industry
(INDA), United States; and the market is growing by approximately 1 to 2 percent annually.
Globally, the medical nonwoven disposables market is forecast to grow to $12 billion annually by
2010, according to market research firm Global Industry Analysts Inc., United States.

Products used inside the body may provide a basis for cells to grow and regenerate tissue –
for example, a ligament that has been destroyed or damaged that can be regenerated using a
bioabsorbable material that eventually becomes indistinguishable from the ligament itself.

Manufacturing processes used to make these medical nonwovens include needlepunch;
hydroentangling; spunbond, meltblown and a combination of the two; and thermal bonding. Bicomponent
splittable or fibrillated fibers, nanotechnology and fiber modification also play important roles
in some recent developments, a number of them involving filtration and barrier technologies.

“Nanofibers are becoming very popular for medical textiles used to filter viruses and
bacteria,” said Jeff Haggard, vice president of technology at United States-based Hills Inc., a
developer of man-made fiber technology and machinery. Hills has been a pioneer in the development
of bicomponent fibers as well as meltblown and spunbond technologies and their applications, and it
offers meltblown technology that can produce fibers in the range between 25 and 400 nanometers
(nm), with an average size of 250 nm.

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The P-CAPT™ filter (top) for removing prior protein from red blood cell concentrate
comprises a target-specific affinity resin sandwiched between nonwoven membranes. Photo and
schematic courtesy of MacoPharma S.A.

macropharm


A Collaborative Development

Collaborations between research institutes and private industry have yielded numerous
important developments in the nonwoven medical textile field. As one example, Pathogen Removal and
Diagnostic Technologies Inc. (PRDT), a joint venture between ProMetic BioSciences Ltd., United
Kingdom, and the American Red Cross, United States, has developed a filter to remove prion protein
from red blood cell concentrate. Prions are responsible for degenerative brain diseases such as mad
cow disease and other such diseases, including its human cousin and the target of this filter,
variant Creutzfeld-Jakob disease. The filter, marketed in the United Kingdom by France-based
MacoPharma S.A. under the brand name P-CAPT™, comprises a target-specific affinity resin sandwiched
between nonwoven membranes using a calendering process. The membrane development was carried out
through a collaboration with the Nonwovens Cooperative Research Center (NCRC) at North Carolina
State University (NCSU), United States. The effort brought together prion experts at the University
of Maryland, and chemical engineers involved in bioseparations and NCRC nonwovens staff and
engineers at NCSU.


Disease Prevention:

Multiple-Use Protection

Current warnings of a swine flu (H1N1) pandemic must be providing a boon to nonwoven face
mask and respirator sales, as people around the world have been shown wearing the masks in an
effort to avoid inhaling the virus or spreading possible infection to others. The US Department of
Health and Human Services has established a website,
www.flu.gov, to provide information about H1N1, avian flu (H5N1)
and pandemic flu in general. The website includes a page with information and guidance provided by
the Centers for Disease Control and Prevention and the Occupational Safety and Health
Administration about the use of masks and respirators to protect against infection. Numerous other
websites offered by health organizations and governments around the world also provide relevant
information.

Mask manufacturers reportedly are escalating their operations to meet the increased demand.
“We’ve gotten some big orders in several countries and are ramping up production,” said John Dolan,
CEO, Carey International Ltd., a United States-based worldwide distributor of a new, multiple-use
respirator mask made with a needlepunched, four-ply fabric comprising two outer layers featuring
Agion® silver/copper zeolite compounds permanently embedded into the fiber and two inner filtration
layers to prevent microbial or other particle penetration. The outer layers have been shown to kill
Streptococcus pyogenes, methicillin-resistant Staphylococcus aureus and other bacteria; and
inactivate H1N1, H5N1, the common cold and other viruses. The filtration layers comply with
National Institute of Occupational Safety and Health N95 and N99 standards.

The N99 mask – certified according to European Respiratory Protection Standard EN149:2001
FFP3 level to have 99-percent or greater particle filtration efficacy, and also approved by
Canadian regulatory agencies – is currently available outside the United States. It has been shown
in trials to be effective for at least 28 days, compared with eight to 12 hours effective use for
standard single-use masks; and the cost per day of use of the mask is about one-tenth of the cost
of a single-use mask.

Bill Hurst, director of business development at United States-based Agion, said the silver
and copper work synergistically to provide faster antimicrobial action than silver alone. “The
ionic exchange between the copper and the sulfur that makes up the bacterium cell membrane helps
compromise that membrane,” he said.


Conclusion

Products such as the P-CAPT blood filter and the N99 respirator mask are but two innovations
being offered in the growing nonwoven medical textile market. New fiber and processing technologies
as well as collaborative, multidisciplinary efforts will contribute to ongoing product development
and further market growth.



October/November/December 2009

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