A Hybrid-Powered Wireless System for Multiple Biopotential Monitoring

Chronic diseases are the top cause of human death in the United States and worldwide. A huge amount of healthcare costs is spent on chronic diseases every year. The high medical cost on these chronic diseases facilitates the transformation from in-hospital to out-of-hospital healthcare. The out-of-hospital scenarios require comfortability and mobility along with quality healthcare. Wearable electronics for well-being management provide good solutions for out-of-hospital healthcare. Long-term health monitoring is a practical and effective way in healthcare to prevent and diagnose chronic diseases. Wearable devices for long-term biopotential monitoring are impressive trends for out-of-hospital health monitoring. The biopotential signals in long-term monitoring provide essential information for various human physiological conditions and are usually used for chronic diseases diagnosis. This study aims to develop a hybrid-powered wireless wearable system for long-term monitoring of multiple biopotentials. For the biopotential monitoring, the non-contact electrodes are deployed in the wireless wearable system to provide high-level comfortability and flexibility for daily use. For providing the hybrid power, an alternative mechanism to harvest human motion energy, triboelectric energy harvesting, has been applied along with the battery to supply energy for long-term monitoring. For power management, an SSHI rectifying strategy associated with triboelectric energy harvester design has been proposed to provide a new perspective on designing TEHs by considering their capacitance concurrently. Multiple biopotentials, including ECG, EMG, and EEG, have been monitored to validate the performance of the wireless wearable system. With the investigations and studies in this project, the wearable system for biopotential monitoring will be more practical and can be applied in the real-life scenarios to increase the economic benefits for the health-related wearable devices

The design of polymeric microneedles for the delivery of sensors for real-time physiological monitoring

Ce mémoire de maîtrise porte sur le développement d’un système d’administration de microaiguilles pour livrer des sondes et des capteurs fluorescents dans le contexte du diagnostic et de la surveillance des soins de santé. Bien que parfois négligés en faveur des soins de santé axés sur le traitement, le diagnostic précoce de la maladie et la surveillance préventive des paramètres biologiques peuvent considérablement améliorer les résultats des soins de santé et joueront probablement un rôle plus important dans les années à venir. Cependant, il reste des obstacles importants à cette approche, à savoir le caractère relativement invasif et perturbateur des analyses biologiques. La nécessité de se rendre dans une clinique et de subir un prélèvement de sang (ou de liquide biologique) invasif présente des inconvénients importants par rapport aux traitements classiques, qui consistent souvent de médicaments pouvant être pris à domicile sans douleur. Une solution à ces problèmes réside dans la mise au point de systèmes minimalement invasifs de diagnostic et de suivi médical, idéalement ceux qui peuvent être utilisés à domicile sans nécessiter de personnel qualifié. À cet égard, les microaiguilles sont une technologie au potentiel énorme, car leur petite taille les rend peu invasives et pratiquement indolores, et leur nature simple à usage unique permet potentiellement une administration à domicile par le patient. Particulièrement prometteuses pour les applications de diagnostic et de surveillance sont les microaiguilles en polymère soluble; fabriquées à partir de polymères synthétiques ou biologiques injectables, ces microaiguilles sont solubilisées après la perforation de la peau, libérant ainsi les composés qu’elles contiennent. Bien que prévu initialement pour la livraison d'agents thérapeutiques, en utilisant ces microaiguilles pour livrer des molécules fluorescentes spécifiquement conçues, il est possible de créer un tatouage médical de diagnostic affichant un signal fluorescent précis. En associant cette technologie à un détecteur de fluorescence portable, la surveillance en temps réel d’un large éventail de paramètres biologiques pourrait devenir accessible en dehors du contexte clinique. Afin de fournir un contexte pour le développement de cette technologie, cette mémoire commence par une revue des principes et des avancées majeures récentes dans le domaine des applications diagnostiques des microaiguilles (Chapitre 1). Par la suite, un tatouage par microaiguille est présenté sous la forme d'un capteur de ROS délivré sur la peau, avec des implications diagnostiques pour le vieillissement et la carcinogenèse de la peau liés aux UV, ainsi que pour des affections inflammatoires telles que le psoriasis, comme validation de concept (Chapitre 2). En outre, un autre tatouage par microaiguille est introduit, consistant d’un capteur spécialement adapté ciblant le système lymphatique, permettant la quantification en temps réel du drainage lymphatique, avec des implications pour la détection précoce de plusieurs affections, notamment le lymphœdème (Chapitre 3).This Master’s thesis concerns the development of a microneedle (MN) delivery system for fluorescent dyes and sensors in the context of diagnostics and healthcare monitoring. While sometimes overlooked in favor of treatment-focused healthcare, early disease diagnosis and preventative monitoring of biological parameters can meaningfully improve healthcare outcomes and will likely play a greater role in coming years. However, significant obstacles to this approach remain, namely the relatively invasive and disruptive nature of biological analyses. The need to travel to a clinic and undergo invasive blood (or biological fluid) sampling presents significant inconveniences relative to common treatments, often consisting of medications that can be taken painlessly at home. A solution to these problems lies in the development of minimally invasive systems for diagnostics and healthcare monitoring, ideally ones which can be used at home without the need for trained personnel. In this regard, MNs are a technology with tremendous potential, as their small size renders them minimally invasive and virtually painless, and their simple, single-use nature potentially allows for at-home administration by the patient. Showing particular promise for diagnostic and monitoring applications are dissolving polymeric MNs; made from injectable synthetic or biological polymers, these MNs are solubilized after breaching the skin, releasing any compound contained within. Though initially envisioned for the delivery of therapeutic agents, by using these MNs to deliver specifically designed fluorescent molecules, it is possible to create a diagnostic medical tattoo displaying a precise fluorescent signal. By pairing this technology with a portable fluorescence detector, real-time monitoring of a wide range of biological parameters could become accessible outside of a clinical setting. To provide context for the development of this technology, this thesis begins with a review of the principles and major recent advances in the field of diagnostic applications of MNs (Chapter 1). Subsequently, a proof-of-concept MN tattoo is introduced in the form of a ROS-sensor delivered to the skin, with diagnostic implications for UV-related skin aging and carcinogenesis, as well as inflammatory conditions such as psoriasis (Chapter 2). Further, another MN tattoo is introduced, consisting of a specifically tailored sensor targeting the lymphatic system, allowing the real-time quantification of lymphatic drainage, with implications in the early detection of several conditions, including lymphedema (Chapter 3)

Low Power Circuits for Smart Flexible ECG Sensors

Cardiovascular diseases (CVDs) are the world leading cause of death. In-home heart condition monitoring effectively reduced the CVD patient hospitalization rate. Flexible electrocardiogram (ECG) sensor provides an affordable, convenient and comfortable in-home monitoring solution. The three critical building blocks of the ECG sensor i.e., analog frontend (AFE), QRS detector, and cardiac arrhythmia classifier (CAC), are studied in this research. A fully differential difference amplifier (FDDA) based AFE that employs DC-coupled input stage increases the input impedance and improves CMRR. A parasitic capacitor reuse technique is proposed to improve the noise/area efficiency and CMRR. An on-body DC bias scheme is introduced to deal with the input DC offset. Implemented in 0.35m CMOS process with an area of 0.405mm2, the proposed AFE consumes 0.9W at 1.8V and shows excellent noise effective factor of 2.55, and CMRR of 76dB. Experiment shows the proposed AFE not only picks up clean ECG signal with electrodes placed as close as 2cm under both resting and walking conditions, but also obtains the distinct -wave after eye blink from EEG recording. A personalized QRS detection algorithm is proposed to achieve an average positive prediction rate of 99.39% and sensitivity rate of 99.21%. The user-specific template avoids the complicate models and parameters used in existing algorithms while covers most situations for practical applications. The detection is based on the comparison of the correlation coefficient of the user-specific template with the ECG segment under detection. The proposed one-target clustering reduced the required loops. A continuous-in-time discrete-in-amplitude (CTDA) artificial neural network (ANN) based CAC is proposed for the smart ECG sensor. The proposed CAC achieves over 98% classification accuracy for 4 types of beats defined by AAMI (Association for the Advancement of Medical Instrumentation). The CTDA scheme significantly reduces the input sample numbers and simplifies the sample representation to one bit. Thus, the number of arithmetic operations and the ANN structure are greatly simplified. The proposed CAC is verified by FPGA and implemented in 0.18m CMOS process. Simulation results show it can operate at clock frequencies from 10KHz to 50MHz. Average power for the patient with 75bpm heart rate is 13.34W