Recent and future developments in health care smart garments
by Zafar Javed, Assistant Professor, National Textile University, Faisalabad.
Published in January, 2008 Issue. http://www.ptj.com.pk
During the last decade or so, an entirely new breed of textile products started to emerge on the research horizons in different parts of the world. It’s a field- variously known as smart fabrics, e-textiles, wearable computers, or intelligent textiles- that many anticipate will become one of the next hot drivers of the modern world economy. Advocates also expect it to propel technology forward in general, because its applications are so diverse.(19) The development of this new field of textile has many motivating factors but out of all those, there are two most significant. One is the tremendous development in the field of microchips and electronics, one time huge mother boards have been converted into pinhead size chips with better functionality than ever before. Second is the death of the traditional textile and clothing industry in Europe, North America and other developed nations. The industry needs more value added products compared to the low cost imports that are flooding these markets. Intelligent textiles and wearable technology is a new exciting research and development area that cross-scientifically implant new properties into traditional products (4).
Research on Smart Textiles is going on with a focus of applications in different fields ranging from Defence systems to the daily life usage. Smart textiles and wearable technology solutions gives added value to a large variety of products. Potential application areas are: (4)
- Health care, e.g. patients’ clothing with integrated sensors.
- Protective clothing for extreme working conditions, e.g. fire fighters.
- Technical textiles.
- Sport and leisure wear.
- Military clothing.
Objectives of this study is to present an overview of the recent developments and future perspectives of the smart textiles technology in the most important field of the application, i.e.
Health care and to identify the prime focus areas toward which the research in this field is pointing. Also to briefly enlist the different products already on the market or will be on the market in very near future.
3. Methods and approach
Methods and approach used was started with the study of the available literature and specifically searching through the World Wide Web. First summarized the basic concept of the smart textiles in general and then described some of the important properties that can be exploited to make use of these textiles in health care in specific. We then analyzed the problems and pitfalls experienced by researchers in this field and also enlisted different products on which research is mainly carried out. Finally we analyzed the potential uses of these products and concluded our study while analysing the future prospects and impacts of these products on human life.
4. Smart Textiles definition
- Smart materials are those which can sense external stimuli and respond with active control to those stimuli.
- The essence of intelligence is the adequate response to a stimulus.
- Intelligence is the ability to learn and to choose responses according to objectives.
In the vision of ambient intelligence, people will be surrounded by intelligent and intuitive interfaces embedded in everyday objects around us and an environment recognizing and responding to the presence of individuals in an invisible way.(21)
Basically two factors are needed, a stimulus and a response to this stimulus. There can be a variety of stimuli, e.g. “electrical impulse, electromagnetic effect, chemical application, biological effect, etc” that can be applied to a textile material and all of these stimuli can be broadly classified into two main groups:
- Chemical based stimuli.
- Electrical based stimuli.
From the afore mentioned definitions we gets an impression that the textile materials are independently capable to respond to the stimulus. This is true in certain cases but in most of the cases the textile materials are made capable of responding by combination of textile material with any other material or structure. The other component can be a chemical or compound or an electronic chip. In many cases textile component is only acting as conductive material or information carrier. There can be countless possibilities in future for the combination of the components, stimuli or the responses but presently the main groups of the intelligent textiles can be briefly described as following.
4.1 Phase Change Material (PCM)
PCMs have high heats of fusion so they can absorb a lot of energy before melting or solidifying. A PCM temperature remains constant during the phase change, which is useful for keeping the subject at a uniform temperature.
4.2 Shape Memory Materials (SMM)
Shape memory is a thermodynamic property possessed by certain materials that, after having been deformed, return to their original shape upon heating or physical material which, after being deformed, returns to its original shape when heated, is classified as shape memory material. (8).Research in the field of the shape memory materials was initiated in the field of metal alloys and later on it found its place in polymeric materials. With the advent of SMMs in polymeric forms it becomes easy to use these in manufacturing of apparels due to their compatibility.
When these shape memory materials are activated in garments, the air gaps between adjacent layers of clothing are increased, in order to give better insulation. The incorporation of shape memory materials into garments thus confers greater versatility in the protection the garment provides against extremes of heat or cold.(24)
4.3 Chromic Materials
Chromism is a process that induces a reversible change in the colours of compounds. In most cases, chromism is based on a change in the electron states of molecules, this phenomenon is (1).The heat stored in the material is released into the environment through a reverse cooling process. During the cooling process, the material temperature decreases continuously. During the complete melting process, the temperature of the PCM as well as its surrounding area remains constant. The undesired temperature increase concomitant with the normal heating process does not occur. The same is true for the crystallisation process. During the entire crystallisation process the temperature of the PCM does not change either. The high heat transfer during the melting process as well as the crystallisation process without temperature change makes PCM interesting as a source of heat storage.(24)
Use of PCM in combination with textile substrate has found wide range of application in extreme sports wear, aviation clothing and health care textiles for maintaining constant temperature thermal control for long duration. Induced by various external stimuli which can alter the electron density of substances.(6) These kinds of substances when used in combination with textile substrate give birth to a class of smart textile materials capable of changing colours under the effect of different stimuli.
Phenomena which involve the change in colour of a material take their name from the type of external influence, either chemical or physical, which ever is involved. Many of these phenomena are reversible. They are:
- Photochromism – colour change caused by light.
- Thermochromism – colour change caused by heat.
- Electrochromism – colour change caused by an electrical current.
- Solvatochromism – colour change caused by solvent polarity.
- Ionochromism – colour change caused by ions.
- Halochromism – colour change caused by a change in pH.
- Tribochromism – colour change caused by mechanical friction.
- Piezochromism – colour change caused by mechanical pressure. (6)
4.4 Conductive Materials
It is a class of textile materials which is capable of conducting electrical current while offering very low resistance to the current flow and on the top of it retaining all the textile properties i.e. flexibility, drapeability, durability and capability of with-standing the textile processing.
Textile materials can be made conductive by many methods which may include manufacturing of fabric with conductive threads/fibres, non-conducting fabric coated with conductive material or engrafting of metallic fibers/particles in the textile fibres. What ever is the method used, basic purpose remains the same and the resulted conductive textile material will either be used as an integral part of a smart system or acting as housing or a data bus for the system.
4.5 Piezoelectric materials
They produce an electric field when exposed to a change in dimension caused by an imposed mechanical force (piezoelectric or generator effect). Conversely, an applied electric field will produce a mechanical stress (electrostrictive or motor effect).
These materials can be applied to the textile substrate in form film fibres. This makes textile material capable of producing voltage in response to a force or vice versa.(18). This property then can be exploited for different uses in daily life from motion tracing of the limbs to pressure sensitive flexible switches in apparels.
5. Smart Textile Materials in Health Care
“Smart textile or Electronic textiles” still are at a ‘black art’ stage. But this industry is in a growth period.”(19) While still in an embryonic stage, the smart and functional textile technology has the potential to become ubiquitous.(20) Fabrics has become an arena for competition for scientists all around the world. The race is on to be the first to develop new fabrics that will not only keep you warm but also cool, dry, moisturised and free of bacteria, odour and stains while measuring your heart rate. Welcome to the world of smart fabrics.(23)
Intelligent biomedical clothing and textiles have the potential to substantially change the provision of health and health care services for large population groups, e.g. those suffering from chronic diseases (such as cardiovascular, diabetes, respiratory and neurological disorders) and the elderly with specific needs. Smart sensor systems and new approaches to analyse and interpret data together with cost-effective telemetric approaches can fundamentally change the interface between citizen/patient and the health care provider.(20) Doctors will be able to remotely monitor a patient’s health statistics and condition. Monitoring the health of newborn babies is another promising application.(22) In future it would be to have every hospital patient wearing a singlet that could monitor their stats and send them remotely to a nurse in a central office.(23) Monitoring of the patients is not only the field of use. Use of textile patches with scaffold for delivery of drug has already been explored by Pharma industry.
Research is not only focused to produce cloths or products for patients but also the clothing or products for the normal citizens where these products need to be easy to wear, elegant, light, etc. This shift of focus naturally follows the transition from the “retrofit” approach to the fully “integrated” approach, and is in progress at technological centres around the world.
6. Applications for smart garments in future.
Out of countless requirements and uses the main obligations that would be acting as driving force for the development of smart garments for health care field are:
- Reducted expeniture cost in terms of managing ageing population, chronic diseases and lifestyle risk factors (obesity, etc)
- Improve care.
- Improve data collection and automatic transmission of physiological or clinical sensitive parameters.
- Reduction of medical errors by allowing the interpretation and extrapolation of index related to physiological conditions by considering all simultaneous data.
- Real time professional consultation.(26)(15)
7. Major applications of Smart & intelligent Garments in Health Care
7.1 Wearable vital sign monitors
When we read about “wearable” computers, we generally see accompanying pictures of awkward-looking college students wreathed in cables and black plastic or adorned with oversized sunglasses with all sorts of bumpy protuberances. But such images are an artifact of the requirement that computers be encased in hard shells. Such a limitation may now be falling away. Recent advances in flexible electronics have made it possible to weave computational intelligence, including both input and output, directly into fabric. (14).Newly developed capabilities of textiles for power transmission, data transfer and sensory functions have provided scientists with an infrastructure for embedded Microsystems.
This has led to the development of wearable monitoring systems for healthcare, with a foresight of removing the restriction of the patient immobility which is an inherent characteristic of conventional monitoring systems.
Clothes are our second skin and have the potential to acquire an additional functionality as a personalized and flexible information platform.(3) They will not only protect but also be capable of interacting with the user and the environment. These systems are envisaged with following enlisted attributes:
- Unobtrusive to user.
- Need minimal or no attention.
- Easily controllable.
- Monitoring of users environment.
- Easy communication interface.
There have been many developments in field of wearable vital sign monitors or this can be said that this is the most focused area of research for application of smart garments in health care.
Application against Sudden Infant Death Syndrome (SIDS)
Sudden infant death syndrome (SIDS) is the sudden and unexpected death of young baby that has no specific cause despite a detailed investigation. It is thought that many SIDS deaths are caused by a breathing failure, but how or why this failure occurs is not known. Possible causes include suffocation, overheating and choking, but none of these has been proven.(27).
One of the early commercial developments is “Mamagoose SIDS Monitor”. It consists of a pyjama with built-in sensors and an electronic signal processing and data collection unit. The pyjama is made of washable textile and guides the movements to the sensors.(12). Mamagoose is developed by using a technology developed by the European Space Agency to monitor the health of adult women and men in orbit, “Mama Goose” pajamas can track a baby’s heart rate and breathing patterns with five sensors. If a problem is detected, the pajamas sound an alarm to help stave off SIDS.(5)
A similar kind of product is developed by VivoMetrics® USA with brand name of LifeShirt®. The LifeShirt is a lightweight (8 oz.), machine washable, comfortable, easy-to-use shirt with embedded sensors. To measure respiratory function, sensors are woven into the shirt around the patient’s chest and abdomen. A single channel ECG measures heart rate, and a three-axis accelerometer records posture and activity level (13)
Wealthy (Wearable Health Monitoring System)
This is an EU funded project assigned to a consortium of companies from different fields to develop a health monitoring system. The main objective of WEALTHY is to set up a comfortable health monitoring system. This will be based on a “wearable” interface, implemented by integrating smart sensors (in fiber and yarn form),
advanced signal processing techniques and modern telecommunication systems on a textile platform and by developing a monitoring system for data management with local intelligence in the form of a decision support unit.(26)
This will be normal flexible garment, capable of monitoring health of the user. The proto type developed is fitted with integrated electrodes for Temperature with ± 0.5oC and heart rate monitoring. On abdomen and arms are fitted piezoresistive sensors for detection of body movement.
A small portable electronic device attached to the garment will be responsible for transmission of data. Data is transmitted in quasi real-time to the remote medical centre using a GPRS link over the standard GSM infrastructure, allowing usage of the garment almost everywhere. The latest version of this Portable Patient Unit has a targeted weight of less than 250g, a size of 110mm x 70mm x 25mm and can so fit in a pocket of the garment.(26)
The WEALTHY Central Monitoring System will be interpreting physical sensor data received from the Portable Patient Unit (PPU) and represent it in simple, graphical form.
A Real-time Wearable System for Monitoring and Analyzing Physiological Signals initiated by Microsoft Research Corporation.(17) HealthGear consists of a set of non-invasive physiological sensors wirelessly connected via Bluetooth to a cell phone which stores, transmits and analyzes the physiological data, and presents it to the user in an intelligible way.
Microsoft claims that their project though has the same objective as of other similar projects but in reality its functionalities are much different and better. They claim that other monitoring systems only are responsible for the transmission of data from the user to a personal computer, either in near vicinity of user or at a remote location. The data then further proceeds by the computer to make it tangible or drawing of some inferences. Secondly the types of sensors used in these systems are of a special kind. In case of the health gear, Microsoft has used the blue tooth connectivity and all the processing of data is being done on a mobile phone. They are also using an open architecture components. The type of sensor is off the shelf pulse oximeter.
Biocloth for Ambulatory Telemonitoring
This is another research project in wearable smart garments funded by French Ministry of Research and new Technologies. It aims at developing generic clothing technology which integrates biosensors and bio-actuators woven into the fabric. In a first prototype version the T-shirt incorporates four smooth dry EKG electrodes, a shock/fall sensor, a breath rate sensor, two temperature sensors and a GPS receiver. A GSM/GPRS module is connected to the T-shirt and is used for data transmission and hands free communication.(16)
This shirt has the same objectives as of the other wearable mentioned above but the main focus presented by them is the integration of the biosensor in the textiles so that a generic clothing technology be developed which is comfortable, resistant and washable.
8.Non-wearable Smart and intelligent textiles in Health Care
8.1 Bed Sensors
This is a product specifically designed for installation beneath a mattress in a nursing home, extended care facility or in the home. This product measures patient motion and agitation and in completely unobtrusive manner.(10) The heart of product is a pressure/displacement sensor Kinotex®. The sensor is fabricated from common polymer foam material such as silicone or urethane. Deformation of the foam generates a change in optical properties proportional to the extent of deformation. A simple optical transducer can sense the change.(7)
Another application is due to appear on the market which produces a pressure image of the patient, and can identify posture, activity, and increasing pressure between the mattress and the patient. This information can be used to perform assessments of a bedridden patient’s risk of developing decubitus ulcers. (10)
8.2 Smart Bandages
Though still in embryonic stage of research but at a fairly advanced stage, smart bandages will be another promising application of smart textiles in health care. The technology is based on the embedded sensors in normal textile material bandage.(9) The technology uses porous silicon, formed from etching millions of tiny holes into a silicon wafer. This is an ideal material for biosensors, first because the porous structure provide a large surface area for contact with target molecules, and second because the nano-crystals present in the structure are photo luminescent in the visible range of the spectrum at room temperature.(9) The porous silicon is then treated with a liquid that contains probe molecules engineered to bind to fat molecules found on the surface of specific bacteria. When the bandage is placed over an infected area, bacteria from the wound move into the porous silicon and attach themselves to the probe molecules, altering the optical properties of the silicon.(25) The change in optical properties can be detected by using handheld laser device thus immediately confirming presence or absence of bacteria.
9. Tribulations in the development of Health Care Smart Garments
Development of the Smart Textiles and then the Smart Garments seems to be a very promising technology of the near future and no doubts it is, but we should be very clear about one thing still at present is that this merger of technologies is at embryonic stage inspite of facts that research is in progress from the last two decades. We yet have to see the products on the shelf of the super store within the buying range of a common consumer.
Currently the research is mainly focused in four areas: Healthcare, Entertainment, Sportswear and Communication.(2) In all four areas there are many problems still to overcome before making claim for the product to be fit for a normal use. The range of problems is very diversified as that of the field itself. The range includes from the mind set of people in their respective technologies to the handling of new materials with conventional textile formation methods.
A wide variety of issues need to be considered in the design and development of a product constructed using a smart textile. Successful design and development takes a panel of multi-disciplinary professionals including textile scientists, polymer chemists, physicists, bioengineers, software engineers, consumer specialists and fashion designers. Finding a common meeting ground is only one of the challenges. With all the jargon associated with each field of expertise disregarding the intimidating technical terminology, it can be impossible to begin a working discourse. There is no doubt that bringing together skilled people from diverse professions, who can effectively communicate, is a hurdle that can’t be dismissed.
For the textile technologist, a host of challenges arise in the fabric forming. As in that of conventional textile piece goods a broken yarn is some time considered harmless provided that it does not offer a major depletion of aesthetic value of the fabric. But in case of smart fabrics, aesthetics is not the major value but it is aesthetic with functionality, which is most important. A single discontinuation in fabric structure can very easily make the fabric of zero value. Some of the conductive yarns are in ribbon form. It is paramount that the ribbon yarns do not twist during fabric forming. In woven fabrics, to avoid twisting in the weft, modifications to the yarn feeders are necessary to properly tension and guide the yarn. When used in the warp in conjunction with traditional yarns, differential yarn take-up can occur. In order to maintain consistent yarn take-up, the ribbon yarn must be fed from a separate creel or warp beam. In case of knitted structures the consideration of knot strength of the yarn/fibre becomes of supreme importance. Weaving fabrics with an electrical network veers from traditional manufacturing. Smart textiles are made in short runs and precision and quality are of the utmost importance. (11).
Like many other modern developments, Smart Textiles are also one of the spin-offs of the research projects for the defence or space applications. This has a bi-directional effect, defence based projects are normally never short of funding but on the other hand they are mostly kept under strict secrecy. The later is seems to be a very prominent factor for not letting the products to be widely commercialized.
Durability is an other major issue. When we think of garments, the first parameters clicks to our mind is the durability, comfort and then the aesthetic value. Most Smart garments still lack these characters though not completely absent, think of wires, strips or electronic chips hidden some where what you are wearing.
There are no doubt that use of Smart Garments for the Health care is the next frontier of the convergence of different technologies at single objective. Presently this may seem to be a cyborg concept but the pace on which the research and development is progressing will soon be able to clear the major road blocks on the way.
There have already been few Smart products on the market, some of them seems not to have received the warm welcome or it is not known widely to users, and others are yet to see the results but efforts are on the way. A strong demonstration of the reliability of these products is needed to create a positive impression on the user’s minds, for changing their cautious approach to confident decisions.
1-Ben Mottinger,Phase Change Materials (PCMs) and Applications, http://www.colorado.edu/engineering/ASEN/asen5519/1999-Files/presentations/ben-mottinger.pdf
2-Busayawan Ariyatum*, Dr. Ray Holland. A Strategic Approach to New Product Development in Smart Clothing. www.idemployee.id.tue.nl/g.w.m.rauterberg/conferences/CD_doNotOpen/ADC/final_paper/135.pdf
3-G. Troster, The Agenda of the Wearable Healthcare, IMIA Yearbook of Medical Informatics 2005: Ubiquitous Health Care Systems. Haux R, Kulikowski C, editors. Stuttgart: Schattauer; 2004. p. 125-138.
4-Heikki Mattila, Project 03123, Nordic CoE for Smart Textiles and Wearable Technology NEST, Final Report
11-http://www.tc2.com/. Dr. Kim Anderson. Smart Textiles Update
14-http://www.worldchanging.com /archives/001555.html (Weaving The Future | JAMAIS CASCIO)
15- IIkka Korhonen IEEE/EMBS Technical Committee on Wearable Biomedical Sensors & Systems
16- J.L. Weber1, D. Blanc1, A. Dittma2, B. Comet3, C. Corr0y4, N. NOuryS, R. BaghaF, S. Vaysse’, A. Blinowska8. Pmc of the 4th Annual IEEE Conf on Information Technology Applications in Biomedicine. UK
17- Nuria Oliver & Fernando Flores, HealthGear: A Real-time Wearable System for Monitoring and Analyzing Physiological Signals, http://research.microsoft.com/~nuria/healthgear/noliver-healthgear.pdf
18- Paula Gould, Oct. 2003 ,Textile Gain Intelligence, http://www.ifmachines.com/materials.
19-Sci/Tech SMART CLOTHES , August 29, 2002 edition, http://www.csmonitor.com/scitech/
20-Smart biomedical clothes promising way to keep the European citizen healthy, http://www.hoise.com/vmw/02/articles/contentsvmw200208.html
21- Smart Clothing, http://www.wearable.ethz.ch/textiles.0.html
22- ‘Smart’ fabrics to keep patients healthy,
23-Smartfabrics, http://www.abc.net.au /catapult /indepth/
24- Smart Wear Lab, http://www.tut.fi/units/ms/teva/projects/intelligenttextiles/
25-Tracy Staedter , Smart Bandage How a smart bandage works, May 2003. http://www.technologyreview.com/index.aspx
26-Wealthy – Wearable Health Care System http://wealthy-ist.com/index.php?action=show_main_page