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This paper describes a microwave resonator incorporating microfluidic lab-on-chip sensor system capable of performing simultaneous differential measurement based sensing of liquid samples. The resonators are split-ring resonator shapes made of gold on glass substrates. Directly bonded on glass substrates are polydimethylsiloxane microchannels. Sensor system design incorporates a pair of identical resonators, one of which performs reference reading from the background. Tracking the difference of the responses of both resonators simultaneously, rather than a single one, is used to obtain a more linear and noise-free reading. The sensor system was produced with conventional fabrication techniques. It is compatible with low-cost, simple, easy to handle sensing applications. Results indicate that reliable differential measurement was possible owing to a well-matched pair of sensors with a response error as low as 0.1%. It was also demonstrated that differential measurement capability enables sensing with improved linearity. Measurements were performed with glucose solutions in the range of 3.2-16.1 mM, achieving a sensitivity of 0.16 MHz/mM.

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Use of microwave resonator-based sensors is a relatively new approach for the detection of biological reagents. Sensing mechanism is based on the tracking of the resonant frequency on electromagnetic resonator. Resonant frequency depends on structure geometry and material but is also affected by secondary changes in environment. Addition of a reference resonator to suppress these effects is proposed in this work. Identical sensor structures designed at 2 GHz, fabricated using low-cost processes are used in experiments to demonstrate the use of a resonator pair for sensing of glucose in solutions, yielding a sensitivity of 34.72 MHz/ (mg/mL).

Although molecular communication systems have been shown to bear great potential for many useful in-body applications, they require the intervention, action, or input of an out-of-body actor. From an Internet of Bio-Nano Things perspective, a successful overall network aims to bring together the two links belonging to the in-body and out-of-body networks for end-to-end communications. For most applications, the uplink from the in-body sensor is more significant since it provides the multi-scalar connection required to relay the information sensed and carried by the molecular communication system to a macro-scale smart terminal. This article proposes two different mechanisms to sense the output of the molecular communication system and transmit the information to an on-body reader. Each mechanism involves different genetically engineered bacteria and specific antenna designs. An experimental setup is provided to demonstrate each proposed concept. The results constitute a proof of concept to detect the in-body bacterial activity from the on-body reader.

Microwave resonator-based sensors offer low-cost, contactless, label-free sensing solutions in a variety of applications. Sensing is done by the observation of the shifts in resonant frequency of the sensor structure, which depends on resonator geometry, material and physical properties of the environment. It is observed that the readings can be significantly affected by changes in secondary physical parameters or sample localization on resonator. A double microwave resonator sensing system incorporating microchannels on glass substrates are proposed to address these challenges. PDMS microchannels bonded on glass substrates are mounted on split ring resonators fabricated via low-cost processes. Experiments are performed with glucose solutions of 1.4 mg/mL–3.0 mg/mL concentration range. Results confirm that the use of double resonators increase rejection of background noise, whereas microchannel use increases measurement stability. Overall measurement sensitivity is shown to be 0.92 MHz/(mg/mL). Further improvements are aimed with the bonding of microchannels directly on resonators fabricated on glass substrates.