Temperature Self-Compensating Intelligent Wireless Measuring Contact Lens for Quantitative Intraocular Pressure Monitoring

Flexible bioelectronic devices that can perform real-time and accurate intraocular pressure (IOP) monitoring in both clinical and home settings hold significant implications for the diagnosis and treatment of glaucoma, yet they face challenges due to the open physiological environment of the ocular. Herein, we develop an intelligent wireless measuring contact lens (WMCL) incorporating a dual inductor-capacitor-resistor (LCR) resonant system to achieve temperature self-compensation for quantitative IOP monitoring in different application environments. The WMCL utilizes a compact circuitry design, which enables the integration of low-frequency and high-frequency resonators within a single layer of a sensing circuit without causing visual impairment. Mechanically guided microscale 3D encapsulation strategy combined with flexible circuit printing techniques achieves the surface-adaptive fabrication of the WMCL. The specific design of frequency separation imparts distinct temperature response characteristics to the dual resonators, and the linear combination of the dual resonators can eliminate the impact of temperature variations on measurement accuracy. The WMCL demonstrates outstanding sensitivity and linearity in monitoring the IOP of porcine eyes in vitro while maintaining satisfactory measurement accuracy even with internal temperature variations exceeding 10 °C. Overcoming the impact of temperature variations on IOP monitoring from the system level, the WMCL showcases immense potential as the next generation of all-weather IOP monitoring devices.

Research Advances on Fiber-Optic SPR Sensors with Temperature Self-Compensation

The fiber-optic surface plasmon resonance sensor has very promising applications in environmental monitoring, biochemical sensing, and medical diagnosis, due to the superiority of high sensitivity and novel label-free microstructure. However, the influence of ambient temperature is inevitable in practical sensing applications, and even the higher the sensitivity, the greater the influence. Therefore, how to eliminate temperature interference in the sensing process has become one of the hot issues of this research field in recent years, and some accomplishments have been achieved. This paper mainly reviews the research results on temperature self-compensating fiber-optic surface plasmon sensors. Firstly, it introduces the mechanism of a temperature self-compensating fiber-optic surface plasmon resonance sensor. Then, the latest development of temperature self-compensated sensor is reviewed from the perspective of various fiber-optic sensing structures. Finally, this paper discusses the most recent applications and development prospects of temperature self-compensated fiber-optic surface plasmon resonance sensors.

Hypersonic Aerodynamic Force Balance Using Micromachined All-Fiber Fabry⁻Pérot Interferometric Strain Gauges

This paper presents high-sensitivity, micromachined all-fiber Fabry-Pérot interferometric (FFPI) strain gauges and their integration in a force balance for hypersonic aerodynamic measurements. The FFPI strain gauge has a short Fabry-Pérot cavity fabricated using an excimer laser etching process, and the deformation of the cavity is detected by a white-light optical phase demodulator. A three-component force balance, using the proposed FFPI gauges as sensing elements, was fabricated, calibrated, and experimentally evaluated. To reduce thermal output of the balance, a simple and effective self-temperature compensation solution, without external temperature sensors, is proposed and examined through both oven heating and wind tunnel runs. As a result of this approach, researchers are able to use the balance continuously throughout a wide range of temperatures. During preliminary testing in a hypersonic wind tunnel with a free stream Mach number of 12, the measurement accuracies of the balance were clearly improved after applying the temperature self-compensation.