Medical textiles

Natural fibers have been used in medical applications since ancient times.^{[11]: 1, 2} The use of splints, bandages, and gauges is very old.^[12] An ancient Sanskrit text on medicine and surgery, the Sushruta Samhita, categorises Kausheya under the "articles of bandaging."^[13] The concept of personal protective equipment (PPE) for medical practitioners dates all the way back to the 17th century. Plague doctor costumes were intended to protect plague doctors from the disease during outbreaks of the Bubonic Plague in Europe. According to descriptions, the costumes were typically composed of heavy fabric or leather and was waxed.^[14][15]

Medical textiles have a critical role in preserving human life. So, e.g., medical textile applications (PPE cover all, N95 masks), were in high demand and scarce supply during the COVID-19 pandemic, resulting in severe shortages.^[7][16][8] Considering the shortage, in February 2020, the World Health Organization restricted the use of medical essentials such as PPE and masks, etc. to front-line workers only (PPE includes gowns, aprons, masks, gloves, medical masks, goggles, face shields, and respirators, i.e., N95 or FFP2).^[17] PPE protects medical professionals from illness, infections [from virus or bacteria]. The PPE cloth acts as a barrier with the capacity to prevent contaminants from entering the body through respiratory secretions, blood, and bodily fluids.^[18]

Masks can protect healthy people from illness by limiting the spread of respiratory droplets and aerosols.^[19]

There are four different groups of fibers, fabrics and materials used in medical textile products.

Different types of fibers and manufacturing systems are utilized for the production of the various medical textile products.^[6]

Extracorporeal devices are the artificial organs that remain outside the body while treating a patient. Extracorporeal devices are useful in hemodialysis and cardiac surgery.^[20][21]

Implants are medical devices used to replace a missing biological structure, to sustain a damaged biological structure, or to improve an existing biological structure. In contrast to a transplant, which is biomedical tissue that has been transplanted, medical implants are man-made devices such as artificial ligaments and vascular grafts, etc.^{[6]: 148 [24]}

Non-implantable materials are used externally and may or may not contact skin. For example, bandages, plaster, orthopedic belts, pressure garments, etc.^{[25][6]: 147, 148}

The term "hygiene and healthcare products" refers to a variety of materials used to maintain the hygiene, safety, and care of medical professionals and patients.^[6]: 157 Surgical drapes, gowns, uniforms, clothing, caps, wipes, masks, and hospital bed linens are all included in this category^[28]

Human textiles refer to textiles that utilize human materials, including bioengineered yarns made from human cells, for tissue regeneration. Textiles manufactured from human tissue-based 'yarn' can be intricately woven, knitted, or braided and have the potential to contribute to various applications, ranging from simple biocompatible sutures to complex woven tissues for surgical repairs, thereby aiding in the healing process of injuries. Human textiles offer a potential solution to mitigate the drawbacks associated with foreign agents that may induce adverse side effects.^[29]

The Cell-Assembled Extracellular matrix (CAM) is both biologically sound and resilient, allowing for large-scale production suitable for clinical applications utilizing regular, adult human fibroblasts.^[29]

In the medical field, most permanent synthetic biomaterials are considered foreign by the innate immune system. This can lead to a foreign body reaction when implanted.^[29][30]

Products made from medical textiles are specially engineered textile-based products used in medical applications. These products are used for prevention, care, and hygiene purposes. A combination of properties are considered while selecting the materials, which largely depends upon the particular use. The materials used in medical textile products must have the following properties: strength, softness, biocompatibility, elasticity, flexibility, nontoxicity, noncarcinogenic, non-allergenic, and air and water permeability.^{[6]: 136, 137}

Biotextiles are constructions made of textile fibers that are employed in both implantable and non-implant applications. Their performance is assessed according to their biofunctionality, biocompatibility, and biostability. For example, biostability in the presence of body fluids and cells.^[31]

Medical devices are commonly made in whole or part from fibers. A medical device is defined as any device intended for medical purposes. It could be a machine, a reagent for use in the lab, software, an appliance, an instrument, or an implant.^[32] For medical use, fiber selection is based on certain criteria of intended use. Primarily, fibers are chosen on the basis of their biodegradability or non-biodegradability. Other than biodegradability, strength, elasticity, and absorbency are also considered.

Natural fibers such as cotton, silk, and viscose (a regenerated cellulosic fiber) are used in hygiene and healthcare products, as well as non-implantable materials. Polyester, nylon, polypropylene, glass, and carbon are all examples of synthetic fibers used in Medical textiles.^[6]: 136 Fibers absorbed within three months by our biological system are considered biodegradable, and fibers that require more than six months to absorb are called non-biodegradable. These fibers are categorized as below:^{[6]: 136, 137}

Polylactic acid, also called PLA, is a biodegradable, biosorbable or bioabsorbable polymer used in producing many type of implants such as naturally dissolving stents.^[6]: 140 Polyglycolide or polyglycolic acid, also called PGA, is a biodegradable and thermoplastic polymer.^[33] PGA suture is categorized as an absorbable synthetic braided multifilament.^[34]

The term "medical textile" refers to various products made of textile materials (fiber, yarn, or fabric) that are used in the medical environment. Although both natural and synthetic fibers are used in medical textiles, properties such as modulus of elasticity, tensile strength, and hardness are mostly fixed factors in natural fibers, and have proven to be more manageable in synthetic fibers.^[11]: 2 Recent fiber developments have a significant impact on four primary areas of medical textiles: hygiene products, implants, non-implantable medical textiles, and extracorporeal medical textiles.^[11]

Medical textiles serve as a bridge between biological sciences and engineering.^{[35]: xxxiii} The advancement of materials science and related research has resulted in the introduction of new fiber materials and manufacturing processes for the medical sector. As a result of new technologies such as 3D printing, electrospinning and melt blowing technology in textiles, medical professions now have access to a diverse choice of textile materials with varying designs and qualities.^[3]

Melt blowing is a well-established technology for fabricating micro- and nanofibers, in which a polymer melt is extruded via small nozzles surrounded by a high-speed blowing gas. Melt-blown microfibers typically have a fiber diameter of 2–4 μm, but can be as small as 0.3–0.6 μm or as large as 15–20 μm. Melt blowing technology helps in producing filtering products such as N95 masks, and female hygiene products.^[36][37]

Medical textiles use tubular fabrics with carefully chosen materials that are biocompatible, nonallergic, and nontoxic. For example, Dyneema, PTFE, Polyester, and Teflon are used for implants. The material type varies depending on the implant area; for example, Polytetrafluoroethylene is preferred for stent implants due to its non-stick properties, while polyolefin is used for mesh implants.^[38][39]

Vectran, a manufactured fiber from liquid-crystal polymer, is used in producing medical devices, for example, implants and certain surgical devices.^[40]

Intelligent textiles can be used for disease management as well as remote monitoring.^[41]: 373 Intelligent textiles can monitor heart rate and blood pressure, which are critical components of medical diagnosis, and controlling them considerably reduces the incidence of serious health disorders. Movement patterns and electroencephalograms are used to diagnose neurological illnesses and to guide treatment decisions.^[41]: 375

Phase-change materials are helpful in medical textiles because they can be utilized to reheat hypothermia patients softly and precisely. Additionally, the PCM can be incorporated therapeutically into elastic wraps or orthopedic joint supports. It makes it easy to provide heat or cold therapy to joints or muscles while wearing a bandage.^{[41]: 54, 55}

Materials with shape-memory polymers that have the capabilities of temperature adaptive moisture management can improve the thermo-physiological comfort of patients.^[42]

Nonwoven fabrics with two or more fibers layers are widely used in a variety of applications, including tissue engineering scaffolds, wipes, wound dressings, and barrier materials.^[43]

Microfluidic spinning technology is used for fabricating many type of fibers. Due to its ease of manipulation, high efficiency, controllability, and environmentally friendly chemical process, microfluidic systems have been identified as an appropriate microreactor platform for the production of anisotropic fibers.^[44][45]