What developers need to know about device-to-skin interface
What do developers of skin-contact devices need to know about the device-to-skin interface? Edith Bianchi, global business development at Med-S2T Solutions explains.
As technology transforms our life and our health, healthcare trends are changing. More and more wearable devices are being developed by leading innovative companies, with great aspirations to lead this revolution. Traditional medical devices are now being replaced by smart and versatile wearable devices used in various applications. This revolution is driven by some major trends such as aging population, chronic illness increase and the desire to improve life-quality and well-being.
Another major driver of wearable technology is the Internet of Things (IoT). It is allowing collected data from ‘things’ to be connected to the cloud, where Artificial Intelligence (AI) can be used to identify trends and enable decisions to be made accordingly. This technological evolution has been integrated into the medical field and is known as the Internet of Medical Things (IoMT).
This shift can potentially transform medical field as we know it today. By using IoMT, we can generate and analyse the collected medical data in a way that was not possible otherwise. Such connected devices are enabling and enhancing possibilities of home-care as well as access to medical experts anywhere. In a world with aging population and massive health expenditures, IoMT may be the very desired means to cope with many of the subsequent challenges. This holds a tremendous value to improve patient personalised care and outcomes. It also carries the potential of creating an efficient way of health monitoring, promoting wellbeing, allowing real-time interventions, progress treatment and adherence and improving the management of chronic disease.
Analysts are estimating the IoMT market will continue its growth trend and simultaneously the worldwide wearables market is forecast to continue its upward trajectory.
On many occasions, IoMT devices are presented in a concept of a wearable device used for applications such as monitoring, diagnostics, neuro-stimulation, smart infusion pumps for drug delivery etc.
When developing such products, our starting point is the patient, in the focus of our product decisions. In most cases the device would be attached to the skin and many times would be used repeatedly. The patient's ‘skin’ interface to the ‘thing’, has been coined by Med-S2T as ‘Skin-to-Thing’. This crucial element is often overlooked by medical device developers, left for a later stage of design. However, it may be the determining factor of implementation of the entire device or technology. The challenge of adhering the device to the skin with medical grade materials in a conformable and cost-effective way, is critical to the success of such wearable devices.
Such a tailored solution requires a multidisciplinary approach and a firm understanding of clinical characteristics, biocompatible materials, human factors and usability as well as the ideal range of capable and reliable manufacturing technologies and suppliers.
Most of R&D engineering team’s focus is rightfully directed to the device itself, to the computing and cloud technologies, to the electronics and to the gateway apps for collecting and analysing the data. Yet, engineering teams must be aware of S2T (Skin-to-Thing) challenges and assume responsibility to understand the requirements and process in developing an optimal Skin-to-Thing solution. The intended wearing location, duration, target population and many other considerations, should dictate the solution, its components, materials, design and production technologies, and these would be better defined if initiated during early stages of development.
The fixation materials industry often describes such solutions as ‘stick-to-skin’ but it is a fairly narrow definiation in my opinion, even if not intended as such. It gives the impression of a simple sticking element while in fact, the challenge of a safe removal of materials as well as an appropriate and conformable attachment to the largest organ in our body – our skin – is not so straightforward. These challeges may be even greater when often the user will be an infant, an elderly patient suffering from health issues such as diabetes, cancer patients and other populations requiring special considerations. Anyone who has ever worn a bandaid on their finger for few hours, can witness the impact of breathability issues and meceration resulting in a wrinkled, whitish appearance to the skin in the treated area. It is obviously much more of a challenge when having a device attached with its weight, dimensions, location and the breathability barrier it creates.
When professionally addressing the development of such skin interface device fixation, one should also be aware of the combination and stack-up of different layers of the patch as well the potential interaction between the different materials and manufacturing technologies. These may all have an impact on the properties and biocompatibility of medical grade materials. This is a challenge which canot be simply adressed by reading the material data sheet. As described in Use of International Standard ISO 10993-1, "Biological evaluation of medical devices, the risk assessment should evaluate not only the materials used in the device, but also the processing of the materials, the manufacturing methods (including the sterilisation process), and any residuals from manufacturing aids used during the process. It takes a multidiciplinary approach and iterative process in order to achieve an optimal and cost-effecive solution with an optimal material selection, design and manufacturing process. A well defined solution and development process will assure an optimal solution which users would be able to easily adopt. It would also mean better time-to-market which is so crucial to any developed innovation.
The awareness of ‘Skin-to-Thing’ and the understanding of its appropriate development process, will certainly make a tremendous contribution to the successful usage and health-benefits of current technological breakthroughs in the medical device, fitness, healthcare and pharmaceuticals industries.