Medical textiles are considered one of the key growth areas in the high-performance technical textiles and apparel industry. It is clearly driving the emergence of new, improved high-tech materials and processes, which is leading to new technological solutions to tackle serious problems. The manufacture of medical textiles involves many different technical fibers/polymers, production processes, and technical finishing processes. By 2020, the growth rates of medical textiles are above average as a result of increases in consumption in the developing countries in Asia and the Western market. The expectancy from medical textiles is rather better, especially, for non-woven materials and disposal of medical textiles in the surgical room. So, medical textiles are defined as technical & high-performance fiber-based products and structures, which are produced for use in a variety of wound and medical applications. Surgical gowns, wound dressings, bandages, artificial ligaments, artificial liver/kidney/lungs, sutures, vascular grafts, artificial joints, contact lenses, artificial cornea, etc. are examples of medical textiles. Textile materials used in medical and applied healthcare & hygiene sectors are an important and growing part of the textile industry. Recently nano-technology has been used in medical textiles to produce nano-coated materials. The global market for medical textiles was valued at around $16.7 million in 2019 and is projected to obtain $23.3 million at a CAGR of 4.9% by 2025. The demand for smart and high-tech medical textile products is increasing day by day. This study shows the application area of textiles in the medical sector.
Textile Materials, Structures and Processes
The use of fibrous materials in medical, healthcare and hygiene products demand many attributes. Fibers used in medical textiles must have the following characteristics:
- It must be non-toxic, non-allergenic and non-carcinogenic.
- It must be biologically compatible with most living systems.
- Are versatile in their physical form.
- Must have good dimensional stability.
- Must be capable of anti-microbial activity, i.e., must be resistant to microorganisms.
- It should be free size, re-washable and re-usable.
- Have good wetting, wicking and fluid control.
- Process good manipulability.
- Where necessary are biodegradable and where necessary are non-biodegradable.
A classification of fibers used in medical applications is made in accordance to their origin and biological resistance:
According to the source of origin
- Natural: cotton and silk are most widely used.
- Synthetic: Polyesters, Polyamide, Polytetrafluoroethylene (PTFE), Polypropylene, Carbon, Glass and Silica.
- Regenerated: Wood pulp, Viscose.
- Specialty: Alginate, Collagen, Chitin, etc.
According to biological resistance:
- Biodegradable: fibers that are absorbed by the body within two to three months following implantation and include cotton, viscose rayon, polyamide, polyurethane, collagen, alginate, polycaprolactone, polypropiolactone and chitin.
- Nonbiodegradable: fibers that are absorbed by the body slowly and take more than six
months to degrade are considered as non-biodegradable. Nonbiodegradable fibers include polyester (e.g. Dacron), polypropylene, polyethylene, nylon, PTFE, and carbon.
The combination of the features of fibers with the properties imparted by the production process will define the functional performance of medical textile products. The below figure shows the relationship between all the key factors involved at different stages of the assembly of medical and healthcare-related products and the functional characteristics of the final product. Fiber structures used in medical & healthcare‐related applications are produced by one of the following technologies: woven, knitted, braided, nonwoven, and composite. The structure formed by the first three processes requires the use of yarns, whereas the nonwoven structures are obtained directly from the polymer extrusion. Composite structures are specially designed and can be made using a combination of the previous processes.
High-Performance Applications of Medical Textiles
Medical textiles manufacturing is the most important part of the textile industry, according to end users and their applications they are classified into four major types:
- Non-Implantable Products: These products are used as external applications on the body and may or may not be in contact with the skin. This type of medical textile should be non-toxic, non-allergenic and non-carcinogenic. There are many more products such as wound dressing, absorbent pads, wound contact layers, gauze pads, bandages, plasters, lint, etc. used as non-implantable fibrous materials.
- Implantable Products: These types of products are used in effective repairing of the body whether in wound closure and surgery replacement. Artificial Tendon, Artificial Ligament, Artificial Skin, Artificial Bones/joints, Artificial Cornea, Vascular Grafts, Heart Valves, Artificial Tendon etc. are examples of implantable fibrous materials.
- Extracorporeal Devices: These are synthetics organs (i.e., artificial organs), which are designed to replace and support the function of some vital organs such as kidneys, liver, and lungs. They are actually mechanical devices, used for blood purification that incorporate textile technology. The artificial kidney is responsible for filtering the unwanted waste materials as a normal kidney will do.
Healthcare and Hygiene Products: The range of applications of these products is vast and varies from the care and safety of healthcare staff/patients. protective clothing, PPE, caps, gowns, surgical masks, bed sheets, curtains, baby diapers, sanitary napkins, etc. are examples of healthcare and hygiene products.
Non-Implantable Materials Used in Medical textiles:
|Fiber Types||Textile Structure||Applications|
|Viscose, lyocell, plastic films||Woven, Nonwoven||Base material|
|Viscose, Polyester fiber, Glass fiber, Polypropylene fiber||Woven, Non-woven, Knitted||Plasters|
|Alginate, chitosan, silk, lyocell||Woven, Knitted, Nonwoven||Wound contact layer|
|Cotton, lyocell, elastomeric fiber||Woven, Knitted||Compression bandages|
|Cotton, wood pulp, linters||Nonwoven||Wadding|
|Cotton, viscose, alginate, chitosan||Woven, Knitted, nonwoven||Gauze dressing|
|Cotton, viscose, lyocell||Nonwoven||Absorbent pads|
Implantable Materials Used in Medical Textiles:
|Fiber Types||Textile Structure||Applications|
|Polyester fiber||Woven, Knitted||Heart valves|
|PTFE fiber, Polyester fiber||Woven Knitted||Vascular grafts|
|Chitin, Silicone, Polypeptides||Nonwoven||Artificial skin|
|PTFE fiber, Silk, Polyamide, Carbon fiber||Woven, Braided||Artificial tendon|
|Silicone, Polyacetyl fiber, Polyethylene fiber, Carbon||Filament form||Artificial joints/bones|
|Collagen, Polyactide fiber, Polyglycolide fiber||Monofilament, braided||Biodegradable sutures|
|Silicone, Collagen fiber||Woven, Braided||Contact lenses, Artificial lumen|
Healthcare and Hygiene Textile Products
|Fiber Types||Textile Structure||Applications|
|Cotton||Woven||Beddings, Sheets, Blankets, Pillowcases|
|Cotton, Polyester fiber||Woven||Clothing uniforms, Protective clothing|
|Polyethylene fiber||Non-woven||Outer layer|
|Viscose, Lyocell||Woven, Non-woven||Clothes/wipes|
|Viscose||Non-woven||Surgical caps and masks|
|Cotton, Polyester fiber, Polypropylene||Woven, Non-woven||Surgical gowns|
|Polyester fiber, Polyethylene||Woven, Non-woven||Surgical covers, Drape clothes|
|Hollow polyester, Hollow viscose||Artificial Kidney||Remove waste materials from patient’s blood.|
|Hollow silicone membrane, Polypropylene fiber||Artificial Lung||Remove carbon dioxide from patient’s blood and supply fresh oxygen.|
|Hollow viscose||Artificial Liver||Separate and dispose of patient’s plasma and supply fresh plasma.|
Artificial Blood Vessel
The structural components of an artificial blood vessel of medium and large diameter are usually PET fibers and PTFE (Polytetrafluoroethylene) membrane. Actually, the size of blood vessels may vary according to the application area and special functions. Artificial blood vessels are also made from electrospun fibers and polycaprolactone nanofibers, which have different diameter ranges. The most challenging thing is blood vessel replacement, which is fine blood vessels below the diameter of 6 mm. Blood cell penetration is increased with the increase of the diameter of blood vessel. Another problem is blood leakage, which is solved by using biocompatible elastic polymers.
Antimicrobial and Antibacterial Textiles
Nowadays, antimicrobial textile is the most common research topic. Here, textile products are treated with biocides, that act against the growth of microorganisms. Silver-based compounds, zinc pyrithione, and triclosan are the main antimicrobial agents used in textiles. On the other hand, the range of antibacterial textiles in the medical sector is increasing day by day, which is able to prevent mite susceptibility to dermatitis, also antibacterial textiles are used in antibacterial wound dressings, patient clothing, bed sheets, or reusable surgical gloves and face masks. Antibacterial wound dressing is one of the important applications of nanotechnology in medical science. Wound dressings are manufactured by bi-layer of silver-coated, high-density polyethylene mesh with a rayon-adsorptive polyester core. Wound dressings are developed by combining electrospun polyurethane nanofibrous membrane and silk fibroin nanofibers.
The artificial kidney (whose module is made up of numerous hollow membrane fibers) is a system that artificially purifies the blood through dialysis. The water and wastes in the blood enter the hollow membrane and spread through the fiber membrane based on their concentration. The inner diameter and thickness of the fiber are 200 and 10 micrometers respectively. Several kinds of materials for hollow membranes have been developed such as regenerated cellulose, triacetate, polyacrylonitrile, polymethylmethacrylate, polyvinyl alcohol, and polysulfone.
The human liver is a type of biochemical laboratory where many biochemical reactions take place. Liver failure can either occur without preceding liver diseases, usually caused either by intoxication, phalloides, acetaminophen or as acute decomposition of chronic liver-related illness. The artificial liver is usually made of hollow membrane fibers like PVA, hollow viscose & triacetate to separate and dispose of patient’s plasmas and supply fresh plasma. A bioartificial liver is an extracorporeal device, through which the plasma is circulated over living and functionally active hepatocytes packed in a bioreactor with the aim to aid the diseased liver until it regenerates and until a suitable graft for transplantation is available. Artificial livers are mainly based on the principle of albumin dialysis or plasma separation and filtration. This device removes both water-soluble substances and albumin-bound without having any synthetic function.
An artificial lung is used as a backup device during heart surgery. Hollow fibers like hollow viscose (pore size is less than 1 micrometer) are a key component in the lung system. Pressured oxygen and carbon dioxide-rich blood is introduced into the inside and the outside space of the hollow fiber respectively, as a result, it removes CO2 from the blood and helps in transporting pure O2. Gas exchange between oxygen and carbon dioxide is carried out by diffusion through the membrane. The gas exchange rate of hollow fiber is extremely high because of a very thin active layer in the middle. This thin active layer is supported by two outer porous layers made from high-density polyethylene. The active layers are consisting of amorphous polyurethane.
Artificial ligaments are used to replace damaged ligaments. Modern artificial ligaments are braided structural components, made of synthetic polymers such as PET, coated with various coatings such as collagen/simvastatin microspheres, are added to improve the biocompatibility of that synthetic polymers. The braided composite material consists of carbon and filaments and forms an artificial ligament to replace the knee ligament. Braided polyester artificial ligaments are very strong and exhibit resistance to creep from the cyclic loads.
Artificial tendons are usually made of PTFE, PET, Polyamide and Carbon fiber. Artificial tendons are composite meshes made up of polyester, polypropylene, and polyester/carbon fiber used for repairing hernia. The utilization of mesh grafts in humans for hernia operations is based on the fact that during the absorption period, a neo-membrane is formed at the site where the mesh has been implanted. A permanent artificial tendon can securely fix a contracting muscle to a bone anchor or any inert prosthesis would meet a serious need in orthopedics, with various applications. The applications of the artificial tendon are rendering complete or segmental prosthetic bones functional, extensive muscle re-direction for the neurological deficit, revision arthroplasty, sports-injury reconstruction etc.
An artificial joint or bone is a prosthetic joint usually made of stainless steel, chromium cobalt, plastic, ceramic, metal or any other inert material, and the textile material present in the joint is Ultra-High Molecular Weight Polyethylene, which is implanted to replace damaged or diseased human joint/bone. A surgeon can replace various joints such as ankles, elbows, hips, knees, shoulders, wrists etc. Ultra-high molecular weight polyethylene is used in artificial hips, knees, ankles, spinal disks and wrists. In the case of bone repairing and bone regeneration, carbon nanotube composite materials are increasingly being used. It is said that carbon-based prostheses are promising materials that imitate the natural function of bones. Artificial joints are usually imported from Germany, France, Switzerland and United States.
Vascular Grafts Vascular and other diseases often interfere with blood flow, vascular grafts are used for its treatment. To increase the blood flow or maintain the proper blood circulation, vascular grafts are replacing the damaged artery or create a new artery. There are two types of vascular grafts: (i) biological & (ii) synthetic. Usually polyester grafts—are used to repair thoracic and abdominal occluded arteries, Dacron grafts—for aortic surgeries, and PTFE grafts—to repair occluded arteries are used. Vascular grafts should be biocompatible, durable, flexible, and resistant to bacteria & sterilization. These are usually made from PET (a) and expanded PTFE (b).
Mechanical Heart Valves
For the treatment of valvular diseases heart valves assist cardiothoracic surgeons. There are mainly two types of heart valves: (i) mechanical valves & (ii) tissue valves. The case of mechanical valves, require periodical checkups and then after a particular time, patients need to be operated on a second time. These devices are used for younger patients only. Mechanical valves are usually made from titanium, around which is a knitted fabric to be stitched to the original tissue called a sewing ring. The sewing ring of the caged-disk type of prostheses uses a silicone-rubber insert under a knitted composite Polytetrafluoroethylene (PTFE) and polypropylene fiber cloth.
Surgical drapes are used during surgery in hospitals, which have imperviousness properties to liquid strike through which bacterial transfer and subsequent contamination of the surgical site can be reduced. Surgical drapes are made of hydroentangled polypropylene face fabric laminated to a microporous breathable film and different tightly woven textiles or knitted cotton, or other fabrics possibly blended with polyester and chemically treated. Disposable surgical drapes are made of non-woven materials of synthetic or natural origin. These materials act as a barrier to most types of viruses and micro-organisms.
There are different types of bandages used in hospitals for various applications area. There are shortly described below:
- Gauze Bandage: Gauze bandages are used in medical hospitals, helps to control bleeding and protect against infection as well. Dressings are pads of gauze placed directly against the wound to absorb blood or other fluids.
- Crepe Bandage: Crepe bandage is also known as elastic bandage or compression bandage. These are used to support the healing of sprains and strains, as the provide very good compression to injured areas of a human body. These are washable and reusable.
- Non-woven Gauze Bandage: These bandages are coated with a strong absorbent capacity of a wound pad, which can be made with or without an adhesive border. This type of bandage is made from viscose rayon and polyester blend fabric with a minimum of 65% viscose content.
- Elastic Adhesive Bandage: These are multifunctional, self-securing first aid bandages, consisting of a woven fabric, elastic in the warp direction and coated with the adhesive mass containing zinc oxide, which may be porous or permeable to water vapor or air.
Suture is an example of a textile biomedical device. Usually, sutures are used as an integral part of all operations, such as, for wound closure to close cuts and incisions and thus prevent infection. These are two types of sutures used in medical hospital: (i) Absorbable sutures and (ii) Non-absorbable sutures. Absorbable sutures can be made from natural and synthetic materials and non-absorbable sutures are made from PTFE, Nylon, Polyester, Silk, Polypropylene etc. In the case of external applications, actually where they are easily accessible, removable and prolonged high strength is required; non-absorbable sutures are generally used.
There are different types of face masks based on the different application areas, among them, surgical mask, N95 mask, KN95 mask are well known to us. Surgical masks are a very important medical device used to protect both patient and operating room personnel from the transferring micro-organisms, body fluids and particulate materials. Surgical masks are made by combining multiple non-woven layers, which are mostly made of polypropylene. The multiple layers prevent the virus & bacteria above 1 micron. Covid-19 has introduced us to a special type of mask called “N95”, which is used in the area, where no oil-based particle is present and its denser filter prevents 95% of particle-sized 0.3 microns and below. This type of mask is made by multiple non-woven layers made of polypropylene.
Surgical gowns are used by the doctors and nurses in the operating theater to prevent the body fluids and transfer of microorganisms from the operating staff to the patient and vice-versa. These are made by using different manufacturing techniques. Mostly made by multiple layers of non-woven fabric, which are made from polyester, polypropylene and polytetrafluoroethylene (PTFE). The outer layer of the surgical gown is made of polypropylene, the middle layer is made of PTFE and the inner layer is made of polyester.
Diaper & Sanitary Napkins
Sanitary napkins are usually composed of three layers. Their inner surface layer that contacts the skin is made of nonwoven, which transfers liquid from the inner surface to the central layer. Its central layer composed of super absorbent polymer absorbs the transferred liquids. Its outer surface layer is usually made of polyethylene (PE) film to guard against the leakage of the liquid. On the other hand, diapers are also made of non-woven. According to the form of a diaper, they can be classified as pant type and pad type. And according to the user, they can be baby diapers & adult diapers for an aged person. But the layer components of diapers are almost the same among all kinds of diapers and are similar to sanitary napkins.
Nano-technology in Medical Textiles
Over the past decade, nanotechnology has received a huge response in the medical textile sector. Nanofiber and nano-coated materials are among the innovations in pharmaceutical production. Nanofibers have gained a touch of nano-technology in the medical sector due to their unique properties such as thin film, nano-scale-based fibers, and lightweight. Some of the unique applications include surgical drapes for the aseptic techniques used in everyday wound dressing, 3-D textiles to prevent and reduce contact irritations and wound infections, and Prostheses with fibers that are able to facilitate the bonding of the implant to the living bone or with resorbable guidance devices for the regeneration of peripheral nerves, Fabrics surface-functionalized and utilized for tissue engineerings such as blood vessel, water repellence, antibacterial control, strength enhancement, muscles, bones & neural tissues, Nonwoven nanofiber filters used in a variety of medical equipment, such as respiratory equipment and transfusion/dialysis machines.
Smart Medical Textiles Technology
Smart medical textile technology has revolutionized the medical & healthcare sector. Smart fabric technology uses different sensors that are able to monitor patients, such as it can control patients’ body temperature and detecting the ideal body temperature. This type of fabric is designed by VTT technical research center in Finland, which detects the patient’s condition and adjusts the temperature according to the patient’s needs by measuring the ambient temperature. Currently, some innovative projects like heart rate measuring clothes, blood vessels, suits for children with disabilities, diagnostic support, disease & infant monitoring, clinical trials monitoring, athletics monitoring, etc. have created new opportunities in this sector.
The Future Prospects of Medical Textiles
The global market size for medical textiles was valued at $ 24.70 billion in 2020 and is expected to reach $ 26.21 billion at a CAGR of 4.5% from 2021 to 2028. The demand for medical textile products is expected to grow on account of the increasing efficient medical treatment and awareness regarding better healthcare services. The growing use of implantable goods, such as artificial tendons, ligaments, lumen, vascular grafts, heart valves, and body part enhancements such as artificial kidneys, liver and lungs is expected to drive the market.
The non-implantable goods segment such as plasters, wound contact layer, compression bandage/elastic bandage, wadding, gauze dressing, absorbent pads, etc. led the market at a CAGR of 4.4% over the forecast period. Growing surgery worldwide is expected to increase demand for non-implantable products, this is because non-implantable products protect wounds and stitches from the environment.
The healthcare and hygiene products segment such as surgical mask, gowns, caps, surgical drapes, wipes, bedsheets, sanitary napkins, incontinence pads etc. led the medical textiles market and accounted for over 45.0% share of the global revenue in the year of 2020. This segment is also expected to the example the highest growth in the upcoming years.
The governments of several countries including the USA, UAE, UK, Brazil, Germany, India and China have constructed new healthcare facilities and expanded existing facilities for the treatment of COVID-positive infected patients to increase the number of hospital beds per 100,000 population. The Asia Pacific dominates the global medical textiles market, accounting for more than 30% of total revenue in 2020. Several countries, including Japan, Taiwan, South Korea, China, India and Indonesia are responsible for the increase in non-woven fabric production.
Europe is expected to exhibit a revenue-based CAGR of 4.2% from 2021 to 2028. It is responsible for increasing healthcare segment spending for the COVID-19 issue in 2020 in several countries, including Germany, UK, Russia, Spain, Italy and France leading to the expansion of existing healthcare facilities such as increasing the number of hospital beds for Covid-19 patients, beds, PPE and the demand for clothing pads is increasing.
Opportunity for Bangladesh in the Field of Medical & Healthcare Textiles
Bangladesh is one of the most populous countries in the world, where there is a huge demand for healthcare. So, there are huge opportunities in the medical & healthcare sector. The effects of COVID-19 have led to a lack of medical safety kits around the world. Bangladeshi manufacturers can think about it if they want and take it as a long-term opportunity. Global fashion brands are canceling their orders, while the demand for safety kits like PPE is increasing around the world. So, factories can immediately make these demand-based safety kits and smart medical textiles and also plan for future business. According to EPB, in the fiscal year of 2020-21, Bangladesh exported PPE & masks worth USD618 million to the global market, which was 23% more than the previous fiscal year. According to BGMEA, about 155 textile industry export masks & PPEs. Masks have been exported to 19 countries and PPEs to 6 countries.
The importance of medical textile technology behind healthy living and improved healthcare is immense. The development of nano-technology and smart clothing items in this sector has reduced the suffering of patients and has taken medical science to a unique level. Research in the developed world such as USA, Japan, China, South Korea etc. is about inventing better and more efficient implantable and non-implantable products. In particular, surgical sutures, vascular grafts, artificial ligaments & tendons are among them. Already their applications have led to the development of new practical productions. But the sad thing is that even though there is research on Medi-technology in developed countries, there is not much research opportunity in Bangladesh. There are many more unknown areas of medical textiles that we should study. We should pay more attention to the production of quality smart medical textiles & related devices. As a result, the market for medical & healthcare textile products in Bangladesh will be bigger and this sector will be able to make a contribution to exports.
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