Effects of inner materials on the sensitivity and phase depth of wireless inductive pressure sensors for monitoring intraocular pressure

2016 ◽  
Vol 108 (10) ◽  
pp. 103701 ◽  
Author(s):  
Cheol-In Jang ◽  
Kyeong-Sik Shin ◽  
Mi Jeung Kim ◽  
Kwang-Seok Yun ◽  
Ki Ho Park ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Pressure Sensors ◽  
Inductive Pressure

Development of Novel Implantable Intraocular Pressure Sensors to Enhance the Performance in in vivo Tests

2015 ◽  
Vol 24 (6) ◽  
pp. 1896-1905 ◽  
Author(s):  
Kyeong-Sik Shin ◽  
Cheol-In Jang ◽  
Mi Jeung Kim ◽  
Kwang-Seok Yun ◽  
Ki Ho Park ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Pressure Sensors ◽  
Intraocular Pressure Sensors

Wireless and continuous intraocular pressure sensors using transparent graphene

2016 ◽  
Author(s):  
Peng Zeng ◽  
Qingsong Cui ◽  
Michael Wu ◽  
Pai-Yen Chen ◽  
Mark Ming-Cheng Cheng
Keyword(s):  
Intraocular Pressure ◽  
Pressure Sensors ◽  
Intraocular Pressure Sensors

scholarly journals Microfabricated Implantable Parylene-Based Wireless Passive Intraocular Pressure Sensors

2008 ◽  
Vol 17 (6) ◽  
pp. 1342-1351 ◽  
Author(s):  
Po-Jui Chen ◽  
D.C. Rodger ◽  
S. Saati ◽  
M.S. Humayun ◽  
Yu-Chong Tai
Keyword(s):  
Intraocular Pressure ◽  
Pressure Sensors ◽  
Intraocular Pressure Sensors

scholarly journals A Flexible and Highly Sensitive Inductive Pressure Sensor Array Based on Ferrite Films

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2406 ◽  
Author(s):  
Xinran Tang ◽  
Yihui Miao ◽  
Xinjian Chen ◽  
Baoqing Nie
Keyword(s):  
Pressure Sensor ◽  
Sensor Array ◽  
Pressure Sensors ◽  
Separation Distance ◽  
Spiral Inductor ◽  
Ferrite Film ◽  
Wearable Electronics ◽  
Highly Sensitive ◽  
Ultrahigh Sensitivity ◽  
Inductive Pressure

There is a rapid growing demand for highly sensitive, easy adaptive and low-cost pressure sensing solutions in the fields of health monitoring, wearable electronics and home care. Here, we report a novel flexible inductive pressure sensor array with ultrahigh sensitivity and a simple construction, for large-area contact pressure measurements. In general, the device consists of three layers: a planar spiral inductor layer and ferrite film units attached on a polyethylene terephthalate (PET) membrane, which are separated by an array of elastic pillars. Importantly, by introducing the ferrite film with an excellent magnetic permeability, the effective permeability around the inductor is greatly influenced by the separation distance between the inductor and the ferrite film. As a result, the value of the inductance changes largely as the separation distance varies as an external load applies. Our device has achieved an ultrahigh sensitivity of 1.60 kPa−1 with a resolution of 13.61 Pa in the pressure range of 0–0.18 kPa, which is comparable to the current state-of-the-art flexible pressure sensors. More remarkably, our device shows an outstanding stability when exposed to environmental interferences, e.g., electrical noises from skin surfaces (within 0.08% variations) and a constant pressure load for more than 32 h (within 0.3% variations). In addition, the device exhibits a fast response time of 111 ms and a good repeatability under cyclic pressures varying from 38.45 to 177.82 Pa. To demonstrate its practical usage, we have successfully developed a 4 × 4 inductive pressure sensor array into a wearable keyboard for a smart electronic calendar application.

scholarly journals Mechanotransduction and dynamic outflow regulation in trabecular meshwork requires Piezo1 channels

2020 ◽  
Author(s):  
Oleg Yarishkin ◽  
Tam T. T. Phuong ◽  
Jackson M. Baumann ◽  
Michael L. De Ieso ◽  
Felix Vazquez-Chona ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Shear Flow ◽  
Aqueous Humor ◽  
Trabecular Meshwork ◽  
Molecular Mechanisms ◽  
Pressure Sensors ◽  
Focal Adhesions ◽  
Ruthenium Red ◽  
Pressure Transducers ◽  
Aqueous Humor Outflow

AbstractMechanosensitivity of the trabecular meshwork (TM) is a key determinant of intraocular pressure (IOP) yet our understanding of the molecular mechanisms that subserve it remains in its infancy. Here, we show that mechanosensitive Piezo1 channels modulate the TM pressure response via calcium signaling and dynamics of the conventional outflow pathway. Pressure steps evoked fast, inactivating cation currents and calcium signals that were inhibited by Ruthenium Red, GsMTx4 and Piezo1 shRNA. Piezo1 expression was confirmed by transcript and protein analysis, and by visualizing Yoda1-mediated currents and [Ca2+]i elevations in primary human TM cells. Piezo1 activation was obligatory for transduction of physiological shear stress and was coupled to reorganization of F-actin cytoskeleton and focal adhesions. The importance of Piezo1 channels as pressure sensors was shown by the GsMTx4 -dependence of the pressure-evoked current and conventional outflow function. We also demonstrate that Piezo1 collaborates with the stretch-activated TRPV4 channel, which mediated slow, delayed currents to pressure steps. Collectively, these results suggest that TM mechanosensitivity utilizes kinetically, regulatory and functionally distinct pressure transducers to inform the cells about force-sensing contexts. Piezo1-dependent control of shear flow sensing, calcium homeostasis, cytoskeletal dynamics and pressure-dependent outflow suggests a novel potential therapeutic target for treating glaucoma.Significance StatementTrabecular meshwork (TM) is a highly mechanosensitive tissue in the eye that regulates intraocular pressure through the control of aqueous humor drainage. Its dysfunction underlies the progression of glaucoma but neither the mechanisms through which TM cells sense pressure nor their role in aqueous humor outflow are understood at the molecular level. We identified the Piezo1 channel as a key TM transducer of tensile stretch, shear flow and pressure. Its activation resulted in intracellular signals that altered organization of the cytoskeleton and cell-extracellular matrix contacts, and modulated the trabecular component of aqueous outflow whereas another channel, TRPV4, mediated a delayed mechanoresponse. These findings provide a new mechanistic framework for trabecular mechanotransduction and its role in the regulation of fast fluctuations in ocular pressure, as well as chronic remodeling of TM architecture that epitomizes glaucoma.

Analytical Modeling of an Implantable Opto-Mechanical Pressure Sensor to Study Long Term Drift

2020 ◽  
Author(s):  
Alex Phan ◽  
Phuong Truong ◽  
Christoph Schade ◽  
Kevin Joslin ◽  
Frank Talke
Keyword(s):  
Intraocular Pressure ◽  
Analytical Model ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Zero Drift ◽  
Membrane Thickness ◽  
Circular Membrane ◽  
Mechanical Pressure ◽  
Bulge Testing

Abstract “Zero-drift” characteristics of an optical intraocular pressure sensor is investigated as a function of membrane dissolution and hygroscopic swelling of the epoxy layer. Both effects were studied using an analytical model based on the deflection of a circular membrane. Results from the analytical model were verified with experimental results from “bulge” testing. The analytical model was used to study the “zero drift” of the sensor as a function of changes in membrane thickness and geometry of the sensor. The results show that dissolution of the membrane and swelling of the spacer layer can contribute to zero-drift over time. The results are useful in guiding design and fabrication optimization to minimize drift in intraocular pressure sensors used for long term implantation.

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