In a recent review published on Communication Materialresearchers reviewed recent improvements in wearable systems for newborns, focusing on wearable skin-attached devices for physiological monitoring across multiple disciplines.
Study: Skin-interfaced wearable biosensors for intelligent monitoring of infant and newborn health. Image credit: Gorodenkoff/Shutterstock.com
Record
Health assessments of infant patients in intensive care could be particularly challenging for patients and their caregivers, as testing settings include several catheters, probes, and electrodes that limit patient movement.
Health assessments generally require expensive and cumbersome instruments to monitor physiological parameters such as respiration rate, heart rate, blood oxygen saturation, temperature, ion concentrations, and blood pressure.
However, in recent decades, scientific progress has led to portable, non-invasive and soft technology to eclipse current procedures.
About the review
In the present review, researchers explored the material basis for wearable devices, focusing on the concepts and technical improvements of key physiological monitoring disciplines such as biodynamics, optics, temperature, electrochemical, and multi-signal sensing.
Hardware development for wearable sensors
Epidermal electronic systems (EES) are soft, flexible electronic devices created using microelectromechanical system (MEMS) technology. These devices have the same material properties as skin, allowing for high flexibility.
Thin-film materials such as polyimide and thin metal deposits can be used as conductive layers, resulting in ultra-thin and flexible devices with sub-nanometer bending stiffness and an effective modulus of 140 kPa.
One can easily apply EES to the skin with a thin adhesive transfer film or wet dressing. The third phase serpentine connects dynamic movement to the skin, high signal quality and continuous contact with the skin surface.
Elastomers, less expensive than silicon wafer technology, are ideal substrates for integrating soft electronics into EES. Elastomeric encapsulation can be used for hybrid electronic systems as it combines flexible EES sensor devices, rigid active and passive electronics, wireless communications and information processing to provide all-in-one equipment that facilitates real-time monitoring.
Textiles are commonly used to incorporate biomarker detection devices due to their convenience and familiarity. Techniques include weaving electrically conductive fibers, stitching on nylon or polyurethane coated with gold or silver, and printing electrical ink onto fibers.
These accessories are easily attached to garments, including belts, belts and coats. Textile electrodes embedded in clothing minimize conductive gel and tape requirements, but reduce signal quality.
Capacitive and resistive voltage responses from conducting fibers can assess physiological parameters such as respiratory rate and motility.
One can transfer data via cable connections or cumbersome wireless transmitters, but antennas could be woven into clothing and combined with RFID tags to transfer data battery-free and wirelessly.
Portable sensors used to monitor physiological conditions
Human bodies generate action potentials through chemical processes monitored by electrodes on the skin. These biodynamic signals are critical for health monitoring, such as electrocardiograms (ECG) for heart activity, electromyography (EMG) for muscle activation, electroencephalograms (EEG) for brain activity, and EEG for eye movement monitoring.
The researchers created an all-in-one EES system to mimic vital sign monitoring in the neonatal intensive care unit (NICU), including wireless inductive power transmission and data exchange to a slot reading platform under the patient’s mattress. The technology is mechanically thin and requires a conductive gel.
EEG is a diagnostic technology that measures the brain’s electrical activity using electrodes implanted in the head. Common methods include single-channel integral-amplitude EEG (aEEG) and multi-channel continuous EEG (cEEG), with cEEG being the gold standard.
There have been some studies on physical redesign of EEG electrode systems. However, most developments involve the development of fabric covers or tapes to improve electrode placement, while still using standard liquid electrodes.
Optical sensing for medical applications uses spectrophotometric principles to non-invasively examine physiological processes transdermally.
The researchers developed a forehead reflection PPG for premature infants, a flexible PPG sensor for the foot, and a wireless system to monitor the baby’s cerebral hemodynamics.
Non-invasive neonatal thin membrane biomarker detection, which focuses on sweat, saliva and urine, can replace standard blood tests in the detection of chemical or protein biomarkers for pre-diagnosis, diagnosis and prognosis of health.
Electrochemical sensing detects charge transfer to a sensing electrode, allowing wearables to record current, conductance, and voltage/potential changes.
The researchers created a multi-signal system that uses two-way ECG and PPG measuring devices to determine pulse arrival time, calculate pulse transit time, and measure seismocardiograms.
conclusions
Based on the review findings, flexible electronic and wearable health monitoring technologies have improved patient outcomes by detecting physiological markers rather than interventional treatments.
Advanced signal processing enables medical applications such as blood pressure and body temperature imaging. The shrinking of electronics has resulted in advances in healthcare, especially in neonatal applications where small footprints, delicate handling and ease of use are crucial.
Portable stethoscopes for asthma monitoring and portable dry cEEGs for seizure monitoring are recent technologies that have simplified treatment options in the ICU. Automated monitoring systems can particularly benefit sick school-age children by increasing independence and self-sufficiency.
