Smart Contact Research Articles

Wireless Communication and Power Harvesting in Wearable Contact Lens Sensors

The human eye contains multiple biomarkers related to various diseases, making electronic contact lens an ideal non-invasive platform for their diagnosis and treatment. Recent advances in technology have enabled the monitoring and diagnosis of glaucoma from Intraocular Pressure (IOP) detection, diabetes from glucose concentration detections, and other biosensors for pH and temperature sensing. Different sensor designs have led to distinct power transfer techniques, among which inductively coupled power transfer is considered most favourable for electronic contact lenses power delivery applications. Therefore, loop antenna, spiral shape antenna, and antenna with nanomaterials such as graphene and hybrid silver nanofibers have been explored under Industrial, Scientific, and Medical (ISM) frequency bands for both Wireless Power Transfer (WPT) and data communication. Notably, spiral antennas are also considered as the component of IOP sensing using capacitive sensors to detect the changes in frequency caused by pressure. This article reviews the state-of-the-art technologies in electronic contact lens sensors and their power delivery techniques. Herein, diverse sensing methods, materials, and power transfer techniques and the promising future trends and challenges in electronic contact lenses have been presented.

A Novel Concept for High Performance Stretchable Li-Ion Microbattery

Energy Storage Microsystems Composed of Thin-Film Devices (supercapacitors and batteries) Have Attracted Attention to Ensure Autonomy of Complex Devices for Wearable Microelectronics. Recently, Flexible Systems Have Been Investigated As Deformation and Integration of Rigid Micropower Sources Cannot be Achieved.1-5 the Technological Challenge Is to Design Energy Storage Devices Showing High Electrochemical Performance with Advanced Mechanical Properties to Prevent Crack Issues during Electrochemical and Mechanical Tests. but in Simple Flexible Micropower Sources, the Strains Experienced By the Active Materials during Bending Usually Remain Well below the Typical Levels Required Leading to Multiple Fractures and Subsequent Loss of Electrical Contact.in This Work,the Fabrication of Microstructured Electrodes Based on Micropillars Supported on Serpentine Interconnects Have Been Achieved By Laser Patterning Technique. Morphological and Chemical Characterizations Confirm the Formation of Independent Micropillars While Preserving the Underlying Current Collector. We Show That Unlike Compact and Continuous Electrode Thin-Films, Vertical Micropillar Structures Supported on Serpentines Can be Stretched up to 70% without Structural Damaging Owing to the Presence of Empty Spaces That Can Prevent the Formation of Cracks and the Electrode Delamination. the Present Approach Based on the Fabrication of Microstructured Electrodes Supported on Serpentine Interconnects Can be Extended to a Wide Range of Materials, Which Opens Promising Perspectives for the Conception of Truly Stretchable Devices Such As Stretchable Micro-Batteries.6,7this Innovative Approach Has Been Used to Fabricate a Flexible Micro-Battery for Powering a Smart Contact lens8 and Garments. the Innovative Micro Battery Approach Relies on Two Flexible Substrates Assembling Consisting of Polydimethylsiloxane (PDMS) Supporting 1 cm2 Surface Area Disk of Lnmo and Lto Serpentine Electrodes Separated By a Gel Polymer Electrolyte.Interestingly, the Micro Battery Shows in the First Reversible Cycle a Charge and Discharge Areal Capacities of 1.22 Mah·cm−2 and 1.196 Mah·cm−2, Respectively. the Coulombic Efficiency for the First Reversible Cycle Corresponds to 96.17%. Regarding the Cycling Performance, the Lto/ Polymer/Lnmo Micro Battery Has Been Assessed at Fast Kinetics for 30 Cycles. the Micro Battery Delivers 73.5 Μah.cm-2 at 6C, 47 Μah·cm−2 at 12C and 32 Μah·cm−2 at 20C with a Remarkable Stability.

A Zwitterionic-Aromatic Motif-Based ionic skin for highly biocompatible and Glucose-Responsive sensor

Electronic skins that can sense external stimuli have been of great significance in artificial intelligence and smart wearable devices in recent years. However, most of current skin materials are unable to achieve high biocompatibility and anti-bacterial activity, which are particularly critical to wearable sensors for neonatal/premature monitoring or tissue-interfaced biosensors (such as electronic wound dressing and smart contact lens). Herein, a zwitterionic-aromatic motif-based conductive hydrogel with electrostatic and π-π interactions is designed for the development of ionic skin sensors. The hydrogel possesses high biocompatibility, anti-bacterial activity, especially glucose-responsive property which has not been achieved by previous ionic skins. Due to its unique molecular design, the zwitterionic-aromatic skin sensor exhibits excellent mechanical properties (robust elasticity and large stretchability) and high-sensitive pressure detection (including a gentle finger touch, small water droplets, and vocal cord vibration). More importantly, aromatic motives in phenylboronic acid segments endow the skin with glucose-responsive property. This skin sensor not only shows great potential in wearable e-skins, but also possesses a promising property for the tissue-interfaced and implantable continuous-glucose-monitor biosensors such as smart wound dressing with a high demand of biocompatibility.

Smart Contact Lenses for Biosensing Applications

Smart contact lenses have emerged as novel wearable devices. Due to their multifunctional biosensing capabilities and highly integrated performance, they provide a great platform for the diagnosis of eye diseases and the delivery of drugs. Herein, a brief history of the development of contact lenses is given. Then, the state‐of‐the‐art design and fabrication of smart contact lenses for biomedical applications, including contact lens materials, fabrication technologies, and integration, are presented. Furthermore, biosensors implemented in contact lenses to measure lactic acid, glucose, intraocular pressure, and other key metabolites in tears are highlighted. Applications of smart contact lenses in drug delivery are also described. These unique features make smart contact lenses promising diagnostic and treatment devices. Challenges and future opportunities for further applications of smart contact lenses in biomedicine are also discussed.

Smart Contact Lenses for Biosensing Applications

Smart Contact Lenses Smart contact lenses are highly integrated devices with multifunctional capabilities for the diagnosis of eye diseases and the delivery of drugs. In article number 2000263, Samad Ahadian, Ali Khademhosseini, and co-workers present a brief history of the development of contact lenses and the state-of-the-art design and fabrication of smart contact lenses for biomedical applications. Challenges and future opportunities for further applications of smart contact lenses are also discussed.

Smart Contact Lenses with a Transparent Silver Nanowire Strain Sensor for Continuous Intraocular Pressure Monitoring.

Continuous intraocular pressure (IOP) monitoring can provide a paradigm shift in the management of patients with glaucoma as a facile alternative to conventional diagnostic methods. However, the low sensitivity and functional instability of current IOP sensors have limited their clinical utility in the management of glaucoma. Here, we have developed a smart contact lens integrated with a transparent silver nanowire IOP strain sensor and wireless circuits for noninvasive, continuous IOP monitoring. After confirming the robust stability of the IOP sensor within the smart contact lens in the presence of tears and repeated eyelid blink model cycles, we were able to monitor IOP changes on polydimethylsiloxane model eyes in vitro. In vivo tests demonstrated that our fully integrated wireless smart contact lens could successfully monitor the change in IOP in living rabbit eyes, which was clearly validated by the conventional invasive tonometer IOP test. Taken together, we could confirm the feasibility of our smart contact lens as a noninvasive platform for continuous IOP monitoring of glaucoma patients.

A 2.5-nW Radio Platform With an Internal Wake-Up Receiver for Smart Contact Lens Using a Single Loop Antenna

The human eye has been considered to be a promising platform for real-time diagnosis of various biomarkers in tears. The smart contact lens (SCL), as a device which directly accesses surface of human eye, is a miniaturized autonomous system integrating all the required functions on the surface of a thin film. This article presents the first implementation of a set of radio including a wake-up receiver required for SCL. The system performs RF transmission upon wake-up call using a single loop antenna. The receiver path has a baseline-tracking offset control loop to successfully detect wakeup signal in the standby state under noisy environment. The operating frequencies for uplink and downlink are 346 and 433 MHz, respectively. A magnetic-coupled wireless charging of an OFF-chip battery is also provided through the same loop antenna. The designed IC is fabricated using 0.18- μm CMOS process, consuming a power of 2.5 nW in wakeup-ready standby state. The IC is also verified with a loop antenna and a thin-film battery integrated on a substrate of SCL.

Smart contact lens and eyelid patch

Materials Science Although chronic ocular surface inflammatory diseases are prevalent, appropriate devices to monitor the disease condition quantitatively in daily life have not yet been developed. Point-of-care devices for controlled therapy in response to biosensing are also not available. Jang et al. report wearable devices for the monitoring and treatment of ocular surface inflammation. A smart contact lens using graphene biosensors integrated with wireless communication units monitors a biomarker of ocular inflammation and sends data wirelessly to a mobile device. A transparent skin patch mounted on the eyelid provides feedback thermotherapy, which is controlled by the mobile device through wireless communication. In vivo applications to animal and human subjects confirmed the potential of this wearable health care platform. Sci. Adv. 10.1126/sciadv.abf7194 (2021).

Smart contact lens and transparent heat patch for remote monitoring and therapy of chronic ocular surface inflammation using mobiles.

Wearable electronic devices that can monitor physiological signals of the human body to provide biomedical information have been drawing extensive interests for sustainable personal health management. Here, we report a human pilot trial of a soft, smart contact lens and a skin-attachable therapeutic device for wireless monitoring and therapy of chronic ocular surface inflammation (OSI). As a diagnostic device, this smart contact lens enables real-time measurement of the concentration of matrix metalloproteinase-9, a biomarker for OSI, in tears using a graphene field-effect transistor. As a therapeutic device, we also fabricated a stretchable and transparent heat patch attachable on the human eyelid conformably. Both diagnostic and therapeutic devices can be incorporated using a smartphone for their wireless communications, thereby achieving instantaneous diagnosis of OSI and automated hyperthermia treatments. Furthermore, in vivo tests using live animals and human subjects confirm their good biocompatibility and reliability as a noninvasive, mobile health care solution.

Cyber-physical spatial temporal analytics for digital twin-enabled smart contact tracing

PurposePhysical gatherings at social events have been found as one of the main causes of COVID-19 transmission all over the world. Smartphone has been used for contact tracing by exchanging messages through Bluetooth signals. However, recent confirmed cases found in venues indicated that indirect transmission of the causative virus occurred, resulting from virus contamination of common objects, virus aerosolization in a confined space or spread from inadequate ventilation environment with no indication of human direct or close contact observed.Design/methodology/approachThis paper presents a novel cyber-physical architecture for spatial temporal analytics (iGather for short). Locations with time windows are modeled as digital chromosomes in cyberspace to represent human activity instances in the physical world.FindingsResults show that the high spatial temporal correlated but indirect tracing can be realized through the deployment of physical hardware and spatial temporal analytics including mobility and traceability analytics. iGather is tested and verified in different spatial temporal correlated cases. From a management perspective of mobilizing social capacity, the venue plays not only a promotion role in boosting the utilization rates but also a supervision-assisted role for keeping the venue in a safe and healthy situation.Social implicationsThis research is of particular significance when physical distancing measures are being relaxed with situations gradually become contained. iGather is able to help the general public to ease open questions: Is a venue safe enough? Is there anyone at a gathering at risk? What should one do when someone gets infected without raising privacy issues?Originality/valueThis study contributes to the existing literature by cyber-physical spatial temporal analytics to trace COVID-19 indirect contacts through digital chromosome, a representation of digital twin technology. Also, the authors have proposed a venue-oriented management perspective to resolve privacy-preserving and unitization rate concerns.

COVID-19 and Your Smartphone: BLE-Based Smart Contact Tracing.

While contact tracing is of paramount importance in preventing the spreading of infectious diseases, manual contact tracing is inefficient and time consuming as those in close contact with infected individuals are informed hours, if not days, later. This article proposes a smart contact tracing (SCT) system utilizing the smartphone’s Bluetooth low energy signals and machine learning classifiers to automatically detect those possible contacts to infectious individuals. SCT’s contribution is two-fold: a) classification of the user’s contact as high/low-risk using precise proximity sensing, and b) user anonymity using a privacy-preserving communication protocol. To protect the user’s privacy, both broadcasted and observed signatures are stored in the user’s smartphone locally and only disseminate the stored signatures through a secure database when a user is confirmed by public health authorities to be infected. Using received signal strength each smartphone estimates its distance from other user’s phones and issues real-time alerts when social distancing rules are violated. Extensive experimentation utilizing real-life smartphone positions and a comparative evaluation of five machine learning classifiers indicate that a decision tree classifier outperforms other state-of-the-art classification methods with an accuracy of about 90% when two users carry their smartphone in a similar manner. Finally, to facilitate research in this area while contributing to the timely development, the dataset of six experiments with about 123 000 data points is made publicly available.

Smart Parking with Fair Selection and Imposing Higher Privacy Constraints in Parking Owner and Driver Information

The use of private cars has enhanced the comfort of travel of individuals, but has proven to be a challenge for parking in congested downtown areas and metropolitans. This hike in the vehicle count has led to difficulty among the drivers to find a parking spot, exploiting resources and time. On the other hand, there are many idle private parking spots that remain inaccessible because of multiple reasons like unavailable owners, different open timings and so on. In order to prevent parking issues as well as to enable the use of private parking spots, smart parking applications that are easy to use by the drivers will prove to be highly effective. However, most parking lot owners and drivers face the threat of privacy which affects their willingness to participate while many others are located in a centralized location where the presence of malicious users is in plenty. In this proposed work, we have introduced a smart-parking system that is based on blockchain exhibiting qualities of privacy protection, reliability and fairness. To protect the privacy of users, vector-based encryption, bloom filters and group signatures are also insisted. This has helped us establish a more reliable smart parking system coupled with fair operation for smart contact. Experimental analysis of the real-world dataset indicates that the proposed work operates with high efficiency, establishing privacy protection, reliability and fairness.

Lente de contacto inteligente: una prometedora herramienta terapéutica en aniridia

ObjectiveTo perform pre-clinical testing using optical design tools to simulate the optical quality of a smart artificial iris platform encapsulated in a scleral contact lens. These tools allow us to generate aniridia eye models and evaluate different metrics of visual quality and retinal illumination based on the aperture of the artificial iris based on liquid crystals. MethodThe OCT imaging technique was used to measure the geometry of the anterior segment in a patient with aniridia and, from these data, the eye model was generated with the Zemax optical design program and specific programs developed in Matlab. Ocular aberrations were calculated and the visual function of the anirida eye model was evaluated in three scenarios: (i) without optical correction, (ii) with correction with a commercial scleral contact lens, and (iii) with correction with an optical lens. intelligent contact based on artificial iris. ResultsOptical quality in patients with aniridia is limited by the magnitude of high-order aberrations. Conventional scleral contact lens design accurately corrects for blur but is unable to compensate for high-order ocular aberrations, especially spherical aberrations. The artificial iris-based smart contact lens design enables virtually all high-order aberrations to be compensated with active control of the pupillary diameter (activation of liquid crystal cells based on ambient lighting). In addition to minimizing high-order aberrations, reducing the pupil size would increase the depth of focus. ConclusionsThis article demonstrates by means of optical simulations the concept of an intelligent artificial iris platform encapsulated in a scleral contact lens and its possible application in patients with aniridia. Furthermore, it allows us to anticipate possible visual results in clinical trials with healthy patients (after application of mydriatic agents) and in patients with aniridia. The results demonstrate a better visual quality and a decrease in retinal illumination.

Tear-Based Aqueous Batteries for Smart Contact Lenses Enabled by Prussian Blue Analogue Nanocomposites.

Batteries for contact lenses fabricated by conventional methods could cause severe damage to the eyes if broken. Herein, we present flexible aqueous batteries that operate in tears and provide a safe power supply to smart contact lenses. Nanocomposite flexible electrodes of carbon nanotubes and Prussian blue analogue nanoparticles for cathode and anode were embedded in UV-polymerized hydrogel as not only a soft contact lens but also an ion-permeable separator. The battery exhibited a discharging capacity of 155 μAh in an aqueous electrolyte of 0.15 M Na-ions and 0.02 M K-ions, equivalent to the ionic concentration of tears. The power supply was enough to operate a low-power static random-access memory. In addition, we verified the mechanical stability, biocompatibility and compatibility with a contact lens cleaning solution. It could ultimately enable a safe power supply for smart contact lenses without risk of injury due to the leakage or breakage of the battery.

49.3: Foveated Contact Lens Display for Augmented/Virtual Reality

49.3: Foveated Contact Lens Display for Augmented/Virtual Reality

The Evolution and Future of Smart Contact Lenses

The Evolution and Future of Smart Contact Lenses

Social Distancing and Isolation Management Using Machine-to-Machine Technologies to Prevent Pandemics

Social distancing and self-isolation management are crucial preventive measures that can save millions of lives during challenging pandemics of diseases such as the Spanish flu, swine flu, and coronavirus disease 2019 (COVID-19). This study describes the comprehensive and effective implementation of the Industrial Internet of Things and machine-to-machine technologies for social distancing and smart self-isolation management. These technologies can help prevent outbreaks of any disease that can disperse widely and develop into a pandemic. Initially, a smart wristband is proposed that incorporates Bluetooth beacon technology to facilitate the tracing and tracking of Bluetooth Low Energy beacon packets for smart contact tracing. Second, the connectivity of the device with Android or iOS applications using long-term evolution technology is realized to achieve mobility. Finally, mathematical formulations are proposed to measure the distance between coordinates in order to detect geo-fencing violations. These formulations are specifically designed for the virtual circular and polygonal boundaries used to restrict suspected or infected persons from trespassing in predetermined areas, e.g., at home, in a hospital, or in an isolation ward. The proposed framework outperforms existing solutions, since it is implemented on a wider scale, provides a range of functionalities, and is cost-effective.

Integrated contact lens sensor system based on multifunctional ultrathin MoS2 transistors

Smart contact lenses attract extensive interests due to their capability of directly monitoring physiological and ambient information. However, previous demonstrations usually lacked efficient sensor modalities, facile fabrication process, mechanical stability, or biocompatibility. Here, we demonstrate a flexible approach for fabrication of multifunctional smart contact lenses with an ultrathin MoS2 transistors-based serpentine mesh sensor system. The integrated sensor systems contain a photodetector for receiving optical information, a glucose sensor for monitoring glucose level directly from tear fluid, and a temperature sensor for diagnosing potential corneal disease. Unlike traditional sensors and circuit chips sandwiched in the lens substrate, this serpentine mesh sensor system can be directly mounted onto the lenses and maintain direct contact with tears, delivering high detection sensitivity, while being mechanically robust and not interfering with either blinking or vision. Furthermore, the in vitro cytotoxicity tests reveal good biocompatibility, thus holding promise as next-generation soft electronics for healthcare and medical applications.

Future biomedical IoT/AI employing electrochemistry and electronics ∼Stand-alone energy-autonomous continuous glucose monitoring smart contact lenses using energy-harvesting-and-sensing-combined integrated system∼

Future biomedical IoT/AI employing electrochemistry and electronics ∼Stand-alone energy-autonomous continuous glucose monitoring smart contact lenses using energy-harvesting-and-sensing-combined integrated system∼

EbolApp – A digital tool for smart contact tracing in infectious diseases (HCID) outbreaks

Background: Outbreaks due to infectious diseases like Ebola virus disease require quick and proper epidemiological responses to implement effective countermeasures. Traditional epidemiological tools are often not easy to apply. PC-based digital tools can be cumbersome in field work. As smart phone adoption is very high in many parts of the world, smartphone-based tools could be an alternative. An app was developed for this purpose and tested in a proof-of-principle study. Methods and materials: EbolApp is an Android-based application that assigns identifiers to smartphones after installation and stores GSM/GPS tracking data on the mobile. With activated Bluetooth function any further device within a defined distance is recorded. If a user contracts a disease, ID-based user profiles are synchronized on a server by an alarm function, which informs any detected contact person and recommends a doctor's visit. Server data will be completely deleted afterwards. Individual movement profiles can be read out by authorized persons. A proof-of-principle analysis regarding compatibility and functionality was carried out by health care workers from a clinic for infectious diseases and tropical medicine. Results: On a total of 16 smartphones with Android version 6, 7 and 8, the app (Version 0.9) was installed without any problems. The complete app functionality was given for 13/16 smartphones (81.3%), no tracking was recorded in two, in one the app crashed while reading profiles. Battery consumption with continuously activated Bluetooth was significantly increased in 50% of users. Thirteen users were able to use the secure alarm function receiving corresponding contact warnings. Graphic mapping and temporal assignment of the motion profiles confirmed the correctness of the alarms. Conclusion: EbolApp is promising digital tool for contact tracing in infectious diseases. It allows fast track detection of contacts and can provide information as well as instructions to those which are at risk. This also may allow timely use of post-expositional vaccinations or medical therapies. The prerequisite is the adequate distribution of appropriate telephones within risk populations and compliance with corresponding data protection laws. In the updated Version 2.0, compatibility of the app has been improved again. A field trial in the Republic of Liberia is on the way.