Preface

Wearable technologies are networked devices equipped with microchips and sensors, capable of tracking and wirelessly communicating information in real time. The rapid adoption of such devices in the past decade has made them the most attractive innovation in the word of technology. From fitness activity trackers to Google Glass, miniaturized wearable devices have shown great potential to be embedded in various domains including healthcare, robotic systems, prosthetics, visual realities, professional sports, and entertainment and arts. Since their first innovation in the 1960s, a wide variety of wearable devices have been developed. These include single functional sensors such as temperature, pressure, and strain detectors, to multifunctional wearable systems capable of monitoring two or more factors simultaneously.

The wearable technologies market is expected to grow 80% from now until 2021, with revenue increasing from \$220 million to approximately \$12 billion. This is attributed to the wide variety of services these products can offer potential customers. For instance, wireless headset technologies, such as Elinka, OldShark, and Goodaa Sunglasses, can provide users the ability to enjoy music as well as answer phone calls while keeping their hands free during walking, biking, or driving. Fitbit fitness watches can continuously monitor heart rate, track activity, and even provide on-screen workouts with no need to be manually configurated on a daily basis. With innovations on the horizon, the future of wearable devices will go beyond answering calls or counting our steps to providing us with sophisticated wearable gadgets capable of addressing fundamental and technological challenges.

This book investigates the development of wearable technologies across a range of applications from educational assessment to health, biomedical sensing, and energy harvesting. Furthermore, it discusses some key innovations in micro/nano fabrication of these technologies, their basic working mechanisms, and the challenges facing their progress.

## **Dr Noushin Nasiri**

Head of NanoTech Laboratory, School of Engineering, Faculty of Science and Engineering, Macquarie University, Sydney NSW, Australia

**1**

Section 1

Health

Section 1 Health

**3**

**2. Tear analysis**

**Chapter 1**

Monitoring

lion world market by 2021 [5].

sensing through noninvasive detection techniques.

*Noushin Nasiri*

**1. Introduction**

Introductory Chapter: Wearable

Wearable technologies are becoming increasingly popular as personal health system, enabling continuous real-time monitoring of human health on a daily basis and outside clinical environments [1–3]. The wearable device market is currently having a worldwide profit of around \$34 billion and is expected to reach above \$50 billion by 2022 owing to wearables' ease of use, flexibility, and convenience [4]. Real-time monitoring, operational efficiency, and fitness tracking are reported as main factors supporting the market growth of health wearable devices such as smart watches, smart glasses, and other wellness gadgets, with expected \$12.1 bil-

In the past decade, the recent progress in developing wearable devices was more focused on monitoring physical parameters, such as motion, respiration rate, etc. [3, 6, 7]. Today, there is a great interest in evolving wearable sensors capable of detecting chemical markers relevant to the status of health. Different approaches have been applied by researchers to design and fabricate wearable biosensors for remote monitoring of metabolites and electrolytes in body fluids including tear, sweat, and saliva [3, 8–10]. A great example would be the development of small and reliable sensors that would allow continuous glucose monitoring in diabetic patients [11, 12]. Diabetes is a chronic disease that can significantly impact on quality of life and reduce life expectancy. However, diabetics can stay one step ahead of the disease by monitoring their blood glucose level to minimize the complication of the disease by proper administration of insulin. Currently, blood analysis is the gold standard method for measuring the level of glucose in patient's blood. However, this technique cannot be applied without penetrating the skin, which can be painful and inconvenient, and requires user obedience. Therefore, current research focuses on the development of portable and wearable devices capable of continuous glucose

A majority of the recent studies in this field have targeted the area of personalized medicine, endeavoring to develop miniaturized wearable devices featuring real-time glucose monitoring in diabetic patients [12–15]. One great example is contact lens which is an ideal wearable device that can be worn for hours without any pain or discomfort [16]. Integration of glucose biosensors into contact lenses

Technologies for Healthcare
