The Rise of Intelligent Sensor Networks
The fourth industrial revolution has led to the development and application of health monitoring sensors that are characterized by digitalization and intelligence. These sensors have extensive applications in medical care, personal health management, elderly care, sports, and other fields, providing people with more convenient and real-time health services. However, these sensors face limitations such as noise and drift, difficulty in extracting useful information from large amounts of data, and lack of feedback or control signals.
The development of artificial intelligence has provided powerful tools and algorithms for data processing and analysis, enabling intelligent health monitoring and achieving high-precision predictions and decisions. By integrating the Internet of Things, artificial intelligence, and health monitoring sensors, it becomes possible to realize a closed-loop system with the functions of real-time monitoring, data collection, online analysis, diagnosis, and treatment recommendations.
Wearable Sensors: Monitoring Vital Signs and Beyond
The continuous advancement of wearable electronics toward multifunctional wearable systems is driven by the desire to improve the quality of life through the enhancement of external device functionality. Presently, commercially available wearable devices such as wristbands, watches, and glasses typically consist of rigid elements with flexible belts that are worn on the human body. However, to further optimize wearable comfort and enable advanced healthcare interactions with humans, wearable electronics are now progressing toward platforms with excellent flexibility, stretchability, and even self-healing capability, benefiting from significant advancements in the development of functional flexible materials.
Wearable sensors have made their way into the field of digital health, finding diverse applications in biomedical settings. These sensors enable the monitoring of vital signs such as respiration rate, heart rate, pulse, skin temperature, and physiological signals such as electrocardiography (ECG), electromyography (EMG), and electroencephalography (EEG). They can also capture body kinetics such as strain and pressure, as well as dynamic biomolecular states through accessible biofluids like sweat and tears.
Recent advancements in wearable sensor technology have demonstrated remarkable capabilities in these areas. For example, the Tunable Ultrasensitive Nature-inspired Epidermal Sensor (TUNES) exhibits the ability to detect a broad range of signals ranging from minute pulses to more substantial muscular contractions and respiration. Another example is the respiratory rate sensor fabricated on a face mask, which functions as a resistive sensor to extract blood pressure information and respiratory rates in real-time with excellent precision.
Temperature sensing also plays a pivotal role in delivering critical data in various scientific and engineering domains. A new approach for creating highly sensitive and flexible artificial skin with a negative temperature coefficient (NTC) thermistor has been developed, enabling continuous and accurate measurement of physiological temperature over long periods.
Accurate recording of human biopotential signals is crucial for diagnosing and treating heart, brain, and muscle-related diseases. A highly conductive polymer dry electrode (PWS) film has been developed, which possesses remarkable attributes such as self-adhesiveness, stretchability, and conductivity, enabling the acquisition of high-quality signals for ECG, EMG, and EEG under diverse conditions.
In addition to monitoring vital signs and physiological signals, wearable chemical sensors have been developed for the real-time detection of biomarkers from biofluids such as tears and sweat. These sensors, utilizing different transduction mechanisms, can detect a wide range of biomarkers, potentially enhancing disease prediction, screening, diagnosis, and treatment.
Implantable Sensors: Monitoring from Within
Compared to wearable sensors that monitor body surface markers, implantable sensors function inside the body and can perform more direct monitoring of healthy states. For example, they can monitor the normal functions of the heart and blood vessels, the recovery progress of injured tissue, and the abnormality of the central nervous signal.
The development of self-powered implantable sensors exhibits the potential to revolutionize healthcare by providing continuous and accurate data without the need for external power sources or frequent replacements. These sensors, based on the principle of triboelectric nanogenerator (TENG), can enable real-time biomedical monitoring, cardiac pacing, muscle/nerve electrical stimulation, tissue regeneration, and drug delivery.
One example is the implantable active pressure sensor (iTEAS), which can convert mechanical signals generated by motion from the implant site into readable electrical signals for analyzing heart rates, blood pressure, blood flow, and respiratory rates. Another example is the self-powered pressure sensor (SEPS) that can be integrated with a minimally invasive implanted heart catheter to monitor intracardiac pressure.
Transient electronics that can be degraded and absorbed within the body after they complete their service have also been developed, saving patients from pain and the risk of infection from a second surgery to remove the implant. These bioresorbable triboelectric sensors (BTS) have the potential to improve patient outcomes by providing accurate and continuous pressure monitoring without the risks associated with permanent implants.
Neural Interfaces: Bridging the Gap between Machines and Nerves
The nervous system is the human body’s control center, regulating organ activity and mediating responses to external stimuli. Monitoring neural electrical signals or neurotransmitters provides insights into physiological and pathological processes, informing the prevention and treatment of neurological disorders. However, it is not easy to accurately acquire and interpret the nerve signals due to their features of weak strength and high noise.
Various neural interfaces (NIs), such as electrode arrays, field-effect transistors (FETs), micronanomechanical systems (MEMS), and nanochannel arrays, have been utilized for measuring neural signals and neurotransmitter concentrations. Improving the adaptability and functions-long-term stability between NIs and neural tissue, improving the high spatial resolution of neural electrodes, and developing neural electrodes that can be integrated with other neural technologies have been long-standing research priorities in this field.
Flexible and intrinsically stretchable implants based on advanced soft materials have been developed to address the mismatch between hard and hydrophobic NIs and the soft and wet nervous tissue, which is the most important cause of immune rejection and nerve electrode failure. These innovative approaches have demonstrated the potential to seamlessly interface with neural tissue, enabling long-term stable and high-quality neural signal recording and stimulation.
AI-Enabled Sensor Systems: Towards Intelligent Healthcare and Biomedical Applications
The integration of artificial intelligence (AI) into sensor technologies holds immense promise for the future of healthcare and biomedicine. One of the key benefits of AI-enhanced sensor systems is the realization of personalized healthcare. By continuously monitoring physiological parameters and seamlessly integrating them with an individual’s medical history, AI algorithms can generate personalized recommendations for disease prevention, early intervention, and chronic disease management.
AI-enabled sensors can also facilitate real-time monitoring of vital signs, enabling rapid detection of abnormalities and timely intervention, potentially saving lives. Empowered by advanced therapeutic devices such as drug delivery patches and neural interfaces, closed-loop sensing-therapy systems emerge as a promising platform to provide enhanced benefits to patients suffering from chronic diseases.
The convergence of AI with self-sustainable IoT systems will enable continuous and pervasive monitoring of an individual’s health status both inside and outside the body. The seamless integration of sensors, AI algorithms, and wireless communication technologies will empower patients to actively participate in their healthcare management, fostering a proactive approach to well-being.
However, the successful implementation of AI-enhanced sensors in healthcare and biomedicine also raises several challenges that should be carefully addressed. Ensuring data privacy and security, addressing regulatory and ethical considerations, and developing robust validation frameworks are critical for building trust in AI-assisted systems.
Conclusion: The Future of AI-Enhanced Sensors in Healthcare and Biomedical Applications
The rapid development of sensor technology has been a driving force behind Industry 4.0, enabling various systems to collect and process data in real-time. The integration of AI data analytics with wearable sensors allows for the capture of crucial information such as muscle deformation, joint bending, temperature changes, and heartbeat frequency, which are invaluable for a wide range of applications encompassing healthcare, environmental monitoring, human-machine interactions, and smart cities.
The future of AI-enhanced sensors in healthcare and biomedicine appears even more promising. The convergence of AI with self-sustainable IoT systems will empower patients to actively participate in their healthcare management, fostering a proactive approach to well-being. Additionally, the widespread adoption of AI in medical research and clinical practice will promote the development of advanced therapeutics and precision medicine tailored to individual patients.
As the technology continues to evolve, AI-enhanced sensors are expected to become an increasingly important tool in healthcare, particularly in the fields of cardiology, neurology, and postoperative care. By harnessing the power of AI and the capabilities of advanced sensor technologies, the healthcare and biomedical industries are poised to undergo a transformative shift, ushering in a new era of personalized, predictive, and preventive medicine.
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