Nanocoatings in medicine

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The global medical device industry has experienced significant growth over the past 5 years. There has been a growing use of anti-bacterial and superhydrophilic nanocoating in medical devices in recent years to combat problems of infection. The medical devices coatings market is estimates to be worth over $5 billion, and nanocoatings can potentially address a significant proportion of this market in the next decade.

Market drivers
Challenges in medical device coatings include:
• biocompatibility;
• coating adhesion;
• uniform coverage over challenging shapes;
• strength;
• durability.
The ability of nanocoatings to meet these needs explains why they are under development for medical device applications. Nanocoating technology has already been widely applied in hearing aid coatings. They are also being increasingly applied in:
• protective coatings for medical electronics;
• lubricious coatings on medical devices;
• anti-bacterial surfaces for medical catheters;
• anti-bacterial coatings on operating tables, door knobs and door handles in hospitals;
• ultra-hard, biocompatible porous coatings for surgical and orthopedic implants like screws, plates or joint implants.

Bacterial infection from medical devices is a major problem and accounts for an increasing number of deaths as well as high medical costs. MRSA is a global problem in healthcare facilities, responsible for up to 50% of hospital infections in the USA and UK. The anti-microbial efficacy of nanoparticle coatings is leading to significant market growth in this application area.
Nanoparticle coatings have been proven to reduce bacterial adhesion and subsequent biofilm formation on medical devices. The nanoparticles are either deposited directly on the device surface, or applied in a polymeric surface coating. The nanoparticle is slowly released from the surface, thereby killing the bacteria present near the surface.
There are significant market opportunities in this sector with the medical catheter market alone projected to reach $22 billion globally by 2012 (ORNL). 10% of patients in ICU’s develop catheter related infections, and 40% of these are acquired during their stay. The market will continue to grow as an aging population will drive more hospital stays and infectious agents (bacteria/fungi) continue to evolve quickly and become less susceptible to antibiotic treatments.
The increased need by an ageing population for spinal, orthopaedic and dental medical devices will also increase demand for medical device coatings with enhanced properties.

Anti-microbial coatings
In medical facilities it is necessary to equip materials and surfaces with a high level of hygiene, using antimicrobial agents to protect them against bacteria and other micro organisms, to prevent infections caused by bacteria and contribute significantly to reducing health costs. The main driver is the prevention of the spread of deadly infections in medical facilities. Drug-resistant bacteria are a growing problem in hospitals worldwide.
Advantages of nanocoatings in the biomedical sector include long lasting anti-microbial effect, constant release of the active substance, effectiveness against bacteria and other micro-organisms, no chemical impurities, easy processing, no changes to the characteristics of the equipped material, and no later discolouration of the equipped material.
Biogate Ag (www.bio-gate.de) equips materials and surfaces in all areas where a high level of hygiene is needed with its antimicrobial agents, consisting out of elemental silver, to protect them against bacteria and other micro organisms.
ItN Nanovation (www.itn-nanovation.de) also manufactures products in this market that are added to paints and lacquers used to coat operating tables, door knobs and door handles in hospitals and surfaces in sanitary facilities. AeonClad Coatings (www.aeonclad.com) nanocoatings increase biocompatibility by treating the surfaces of medical devices, stents, and catheters with ultra thin, ultra smooth coatings that better prevent protein and bacterial attachment.

Medical implants
The properties sought for medical implants such as mechanical stability, thermal/electrical conductivity, diffusion, water absorption, biostability and biocompatibility are all greatly enhanced at the nanoscale.
The biocompatibility of medical devices, stents, and catheters is improved with ultra-thin, ultra smooth coatings that better prevent protein and bacterial attachment. These nanocoatings allow for prevention of bio film, lubrication and cell adhesion for medical implants.
Anti-infective nanoscale coating materials improve the efficacy of indwelling and implantable medical devices, while reducing the risk of deadly medical device-related infections. Self-cleaning coatings have application for improved biocompatible surfaces able to prevent cells from adhering to implanted medical devices.
Nanostructured materials can stimulate self-healing cell responses or can increase the biocompatibility of implants. Nanomaterials are also being utilized the coating of vascular stents. Nanoporous alumina and hydroxyapatite coatings increase biocompatibility and thus efficient stenting.
Companies developing nanocoatings for medical implants include Inframat (www.inframat.com) and Debiotech SA (www.debiotech.com).
Nanocrystalline metalloceramic coatings have been applied to orthopedic and dental implants for increased biocompatibility, and can provide a huge increase in binding to bone proteins compared to conventional coatings. Nanoporous alumina is also under development for use on titania alloys. Nanovis Incorporated (www.nanovisinc.com) is developing nanopatterned implant surfaces for the degenerative spine implant market. Acrymed, Inc. (www.acrymed.com) develops anti-infective nanosilver coatings for implants. Namos GmbH (www.namos.de) also produces nanostructured functional surface coatings for implants. Nanoparticulate zirconium oxide is also widely used in dental implants.

Medical textiles
Medical textiles is the fastest growing niche textiles market. Nosocomial infections-defined as infections not present and without evidence of incubation at the time of admission-are a significant problem for hospitals. Between 3 and 10% of inpatients acquire an infection during their hospital stay. The mortality rate for nosocomial infections is 1%, and they contribute to 3% of mortality from other diseases. It is estimated that there are over 4 million hospital-acquired infections each year in Europe. These alarming statistics has driven the need for development of anti-bacterial coated medical textiles, as nosocomial infections of endogenous origin occur mainly as a result of contact with hospital gowns and sheets. Anti-bacterial medical textiles incorporating nanoparticle zinc oxide and nanosilver are already on the market. They are used on wound dressings and medical textiles for topical and prophylactic antibacterial treatments, point-of-use water treatment to improve the cleanliness of water and antimicrobial air filters to prevent bioaerosols accumulating in ventilation, heating, and air-conditioning systems. Next generation products will utilize nanoparticle coated fibers that control the delivery of medicine and administer time released anti-bacterial and anti-allergenic compounds.

Companies
AcryMed, Inc., USA
www.acrymed.com
The company’s proprietary SilvaGard® is a surface-engineered antimicrobial method for creating silver nanoparticles on surfaces of devices to impart programmable duration of anti-infective properties to the surface without altering the substrate’s mechanical or physical properties. These wound-healing and anti-infective coatings for medical devices are durable on multiple types of substrates, including glass, rayon, stainless steel, polyester, silicon, polypropylene, silicon, polyimide, polyethylene, titanium, polyurethane, ceramic, cotton, and more. Additional formulations for controlled release antimicrobials include use in thin films, foams, topicals, and hydrogels.

BioGate AG, Germany
www.bio-gate.de
The company manufactures silver nanoparticles for antimicrobial agents and coatings. HyProtect is a plasma coating made of pure silver utilizing a PVD process that is applied to medical devices.

Bioni CS GmbH, Germany
www.bioni.de
Working with research scientists at the Fraunhofer Institute for Chemical Technology, Bioni CS GmbH developed an anti-bacterial coating, Bioni Hygienic that contains silver nanoparticles that destroy mold and mildew, fungi spores, and bacteria on contact. The coating has application in medical facilities and sensitive building applications such as schools, bathrooms, food industry facilities, and retirement homes. Additional applications being explored include dental implants, synthetic bones, catheters, artificial heart valves, food packages, and toys.

DSM Biomedical, Germany
www.dsm.com
ComfortCoat is an antimicrobial coating (silver) combined with a hydrophilic coating for application in medical devices. The DSM ComfortCoat® Hydrophilic Coating was designed to enhance maneuverability of devices in minimally invasive procedures.

ItN Nanovation AG, Germany
www.itn-nanovation.com
Nanozid is added to paints and lacquers used to coat operating tables, door knobs and door handles in hospitals (e.g. “clean rooms”) and surfaces in sanitary facilities. In addition to their obvious utility in the clinical sector, biocidal coatings have numerous applications in the food and beverage industries and in HVAC systems, which frequently serve as vehicles for the spread of infectious diseases. The company licenses intellectual property to development partners and customers for their products. They possess over 230 patents. Rusnano acquired a 29.9% stake in ItN Nanovation AG in May 2011.

N2 Biomedical, USA
www.n2bio.com
Spi-Argent is a nanocrystalline silver-based antimicrobial coating applied using ion beam assisted deposition. This minimally eluting film is long-lasting, has broad-spectrum effectiveness, and does not possess the drawbacks typical of antibiotics such as bacterial resistance. Spi-Argent can be applied to a multitude of substrates including PET, stainless steel, cobalt-chromium, silicone, and titanium.

Nano Hygiene Coatings Ltd., UK
www.nanohygienecoatings.co.uk
The company’s coatings are being developed for a wide variety of industries, including medical, healthcare, food and drink, dairy, HVAC, rail etc. Development is mainly done in the UK and liquid formulations of up to 1 tonne are sold. The main target market is medical hygiene, for medical devices and surface hygiene. A secondary hygiene market being looked at is for surfaces in hotels and catering. The USA market is under development. They have conducted milk testing on coated and uncoated surfaces.

NanoTouch Materials, LLC, USA
www.nanotouchmaterials.com
NanoSeptic are anti-bacterial nanocoatings. The self-cleaning surface constantly traps and kills bacteria, viruses and fungi through a catalytic oxidation process using available light. Bellmore-Merrick School District in New York is adopting self-cleaning NanoSeptic® surfaces in and out of the classroom. Other schools have brought the portable NanoSeptic surfaces into the classroom in the form of snack mats and desk mats.

Surface SolutionS Group LLC, USA
www.surfacesolutionsgroup.com
FlouroMed is an antimicrobial coating (silver) developed for medical devices/instruments. Many surgeries today are performed using coated medical electrosurgical blades, forceps, catheters, coated mandrels and devices with handles requiring non-stick, electrical insulation and other properties. Xylan® coatings, PEEK® coatings, KYNAR® coatings, HALAR® coatings, nylon coatings and many other medical grade coatings provide these properties.

 

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