ABSTRACT
The key to fight against a global pandemic such as COVID-19 is to have low-cost, reliable and fast response diagnostic tools. Electronic biosensors are preferred because of their ease of integration into current centralized health care networks and integration with modern point-of-care testing (POCT) devices. Printed electronic sensors provide a sensitive and reliable diagnostic platform to aid in controlling transmissible diseases. In this work, we demonstrate a fully printed capacitive biosensor. The sensor uses coplanar electrodes, coupled with capture antibodies immobilized on microporous Polyvinylidene-fluoride (PVDF) film to detect the SARS-CoV-2 spike protein in spiked buffer solutions. Antibody immobilization on PVDF surface is confirmed with confocal fluorescent imaging microscopy. Gold nanoparticle (GNP) tagged detection antibodies are also introduced to provide increased sensitivity. The gold nanoparticles provide a reflectance layer which leads to increased capacitance. This increased capacitance can be measured directly and has demonstrated the ability to screen for spiked samples with statistical significance. This fully printed capacitive immunoassay has the potential to be used as a transmissible disease screening and vaccine efficacy assessment tool for resource-limited areas. IEEE
ABSTRACT
Respiration monitoring is a very important indicator of health status. It can be used as a marker in the recognition of a variety of diseases, such as sleep apnea, asthma or cardiac arrest. The purpose of the present study is to overcome limitations of the current state of the art in the field of respiration monitoring systems. Our goal was the development of a lightweight handheld device with portable operation and low power consumption. The proposed approach includes a textile capacitive sensor with interdigitated electrodes embroidered into the facemask, integrated with readout electronics. Readout electronics is based on the direct interface of the capacitive sensor and a microcontroller through just one analog and one digital pin. The microcontroller board and sensor are powered by a smartphone or PC through a USB cable. The developed mobile application for the Android™ operating system offers reliable data acquisition and acts as a bridge for data transfer to the remote server. The embroidered sensor was initially tested in a humidity-controlled chamber connected to a commercial impedance analyzer. Finally, in situ testing with 10 volunteering subjects confirmed stable operation with reliable respiration monitoring.
Subject(s)
Masks , Respiration , Humans , Monitoring, Physiologic , Smartphone , TextilesABSTRACT
The flexible and wearable capacitive sensors have captured tremendous interest due to their enormous potential for healthcare monitoring, soft robotics, and human−computer interface. However, despite recent progress, there are still pressing challenges to develop a fully integrated textile sensor array with good comfort, high sensitivity, multisensing capabilities, and ultra-light detection. Here, we demonstrate a pressure and non-contact bimodal fabric-only capacitive sensor with highly sensitive and ultralight detection. The graphene nanoplatelets-decorated multidimensional honeycomb fabric and nickel-plated woven fabric serve as the dielectric layer and electrode, respectively. Our textile-only capacitive bimodal sensor exhibits an excellent pressure-sensing sensitivity of 0.38 kPa−1, an ultralow detection limit (1.23 Pa), and cycling stability. Moreover, the sensor exhibits superior non-contact detection performance with a detection distance of 15 cm and a maximum relative capacitance change of 10%. The sensor can successfully detect human motion, such as finger bending, saliva swallowing, etc. Furthermore, a 4 × 4 (16 units) textile-only capacitive bimodal sensor array was prepared and has excellent spatial resolution and response performance, showing great potential for the wearable applications.
ABSTRACT
In the capacitive proximity sensing method, arranging multiple sensing electrodes makes it possible to obtain the three-dimensional position of a nearby object. The author has developed a capacitive proximity sensing method using LC resonance in three reactance elements. In this method, the detectable area can be greatly extended by the floating electrodes, which are capacitively connected to the sensing electrode. By connecting multiple floating electrodes in series, the detectable range can be extended up to the length of the array of floating electrodes. When these electrodes are arranged on a frame, the region surrounded by the frame becomes the detectable area. By applying this frame on any surface, it is possible to make the surface within the opening of the frame a non-contact operating panel, which can be applied as a gesture input device.