Highly Sensitive and Patchable Pressure Sensors Mimicking Ion-Channel-Engaged Sensory Organs

Abstract

Biological ion channels have led to much inspiration because of their unique and exquisite operational functions in living cells. Specifically, their extreme and dynamic sensing abilities can be realized by the combination of receptors and nanopores coupled together to construct an ion channel system. In the current study, we demonstrated that artificial ion channel pressure sensors inspired by nature for detecting pressure are highly sensitive and patchable. Our ion channel pressure sensors basically consisted of receptors and nanopore membranes, enabling dynamic current responses to external forces for multiple applications. The ion channel pressure sensors had a sensitivity of ∼5.6 kPa(-1) and a response time of ∼12 ms at a frequency of 1 Hz. The power consumption was recorded as less than a few μW. Moreover, a reliability test showed stability over 10 000 loading-unloading cycles. Additionally, linear regression was performed in terms of temperature, which showed no significant variations, and there were no significant current variations with humidity. The patchable ion channel pressure sensors were then used to detect blood pressure/pulse in humans, and different signals were clearly observed for each person. Additionally, modified ion channel pressure sensors detected complex motions including pressing and folding in a high-pressure range (10-20 kPa).

Stomata‐Inspired Photomechanical Ion Nanochannels Modified by Azobenzene Composites

“…By a supplier, the pore density is 6 × 10 8 , 4 × 10 8 , and 2 × 10 7 pores per cm 2 corresponding to 10, 100, and 1000 nm in pore diameter sizes, respectively. We considered previously that the current changes seem to be saturated, at the pore size less than 100 nm . However, in this study, light stimulation of pores with small original diameters under 100 nm yielded more efficient performance results.…”

“…We considered previously that the current changes seem to be saturated, at the pore size less than 100 nm. [11] However, in this study, light stimulation of pores with small original diameters under 100 nm yielded more efficient performance results. Pore size changes were achieved through supermolecular actuation on surfaces coated with AZO-PDDA.…”

“…This phenomenon can be calculated by estimating the ratios of the effective surface areas. One example of such a calculation is the ratio of effective pore surface areas 1:66:333 corresponding to 10:100:1000 nm in pore diameters . That is, when the pore size of the membrane is small, AZO–PDDA is coated on a larger surface area, indicating that small diameter pores corresponds to large surface area.…”

“…One example of such a calculation is the ratio of effective pore surface areas 1:66:333 corresponding to 10:100:1000 nm in pore diameters. [11] That is, when the pore size of the membrane is small, AZO-PDDA is coated on a larger surface area, indicating that small diameter pores corresponds to large surface area. More effective pore actuation occurs in a membrane with a larger coated area and smaller pore sizes during irradiation.…”

Bioinspired Fluffy Fabric with In Situ Grown Carbon Nanotubes for Ultrasensitive Wearable Airflow Sensor

“…Flexible airflow sensors are particularly useful in transmitting information according to Morse code by blowing the sensors, monitoring increasing and decreasing airflow velocity, and alerting blind people walking outside about potential hazard induced by nearby fast-moving objects.Traditional airflow sensors have been developed and used in weather monitoring, biomedical engineering, aerospace, and mineral enterprise. [17][18][19] The working mechanism of the reported airflow sensors includes measuring either the airflow-induced temperature variation [20][21][22] or the airflow-induced mechanical deformation which can be further characterized using piezoresistive, [8,[23][24][25] capacitive, optical, [16,26] or piezoelectric [27,28] approaches. However, those conventional airflow sensors are rigid, cumbersome, [20][21][22] and have high detection limits, [27,28] making them unsuitable for applications in wearable electronics.…”