This paper proposes a self-powered disposable supply-sensing biosensor platform for big-data-based healthcare applications. The proposed supply-sensing biosensor platform is based on bio fuel cells and a 0.23-V 0.25-μm zero-V _th all-digital CMOS supply-controlled ring oscillator with a current-driven pulse-interval-modulated inductive-coupling transmitter. The fully digital, and current-driven architecture uses zero-V _th transistors, which enables low voltage operation and a small footprint, even in a cost-competitive legacy CMOS. This enables converterless self-powered operation using a bio fuel cell, which is ideal for disposable healthcare applications. To verify the effectiveness of the proposed platform, a test chip was fabricated using 0.25-μm CMOS technology. The experimental results successfully demonstrate operation with a 0.23-V supply, which is the lowest supply voltage reported for proximity transmitters. A self-powered biosensing operation using organic bio fuel cells was also successfully demonstrated. In addition, an asynchronous inductive-coupling receiver and an off-chip inductor for performance improvement were successfully demonstrated.

In this paper, we present a self-powered bio-sensing system with the capability of proximity inductive-coupling communication for supply sensing and temperature monitoring. The proposed bio-sensing system includes a biofuel cell as a power source and a sensing frontend that is associated with the CMOS integrated supply-sensing sensor. The sensor consists of a digital-based gate leakage timer, a supply-insensitive time-domain temperature sensor, and a current-driven inductive-coupling transmitter and achieves low-voltage operation. The timer converts the output voltage from a biofuel cell to frequency. The temperature sensor provides a pulse width modulation (PWM) output that is not dependent on the supply voltage, and the associated inductive-coupling transmitter enables proximity communication. A test chip was fabricated in 65 nm CMOS technology and consumed 53 μW with a supply voltage of 190 mV. The low-voltage-friendly design satisfied the performance targets of each integrated sensor without any trimming. The chips allowed us to successfully demonstrate proximity communication with an asynchronous receiver, and the measurement results show the potential for self-powered operation using biofuel cells. The analysis and experimental verification of the system confirmed their robustness.

This work presents the lowest-current fully-integrated sub-mm³ OOK transmitter, the transmission of which is modulated by its supply voltage. By combining the transmitter with a glucose fuel cell which functions as both the power source and sensing transducer, a self-powered CGMS contact lens can be emerged. The prototype in 55-nm deeply depleted channel (DDC) CMOS with on-chip inductor and antenna requires an average current of 6.1 nA under 0.32-V supply without any external signal, which demonstrates the potential of self-powered operation.

An extended-gate CMOS sensor array with enzyme-immobilized microbeads for redox-potential glucose detection is demonstrated for the first time. Redox-potential detection has the possibility to achieve high accuracy because it is not affected by the buffer conditions. Despite this high-accuracy property, redox-potential detection requires a sufficient amount of enzyme, which leads to increased cost. In order to reduce the enzyme consumption while maintaining the detection capability, we have introduced enzyme-immobilized microbeads. By using the microbeads, the enzyme can be efficiently positioned and reused several times. Thus, the required amount of enzyme can be reduced dramatically. To verify the proposed concept, we have developed and measured a prototype with a 0.6-μm CMOS test chip including the microfluidics. Measurements successfully demonstrate glucose detection with a sensitivity of -61.6 mV/decade while reusing identical enzyme-immobilized microbeads.

A fully integrated CMOS circuit based on a vector network analyzer and a transmission-line-based detection window for circulating tumor cell (CTC) and exosome analysis is presented for the first time. We have introduced a fully integrated architecture, which eliminates the undesired parasitic components and enables high-sensitivity, to analyze extremely low-concentration CTC in blood. The detection window was designed on the high-sensitive coplanar waveguide line. To validate the operation of the proposed system, a test chip was fabricated using 65-nm CMOS technology. Measurements were performed after adding a tiny lump of silicone or a droplet of water on its detection window. The measured results show |S_21| degradation of -1.96 dB and -6.04 dB for the silicone and the droplet, respectively, at 1.4 GHz. In addition, in another measurement using magnetic beads, it is confirmed that the proposed circuit can analyze even low concentrations of 20 beads/μL. As well as microbeads, measurement with CTCs was successfully demonstrated.

This letter presents the first solar cell (SC)-powered biofuel cell (BFC)-input biosensing system with pulse interval modulation (PIM) and pulse density modulation (PDM) LED driving capability for continuous glucose monitoring (CGM) contact lenses featuring stand-alone RF-less operation. Power supply from on-lens SCs can eliminate the necessity of wireless power delivery, and LED implementation can eliminate the necessity of wireless communication. By employing the BFC-input approach instead of using a power-hungry potentiostat, powering and sensing components are separated, which reduces the power budget from SCs. The measured power of 28/144 nW at the PIM/PDM mode with a 0.31/0.39-V supply voltage can be managed by the on-lens SCs, enabling a fully stand-alone on-lens operation under office-room ambient light whose typical illumination intensity is 800–1600 lx.