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... Finite State Machine: To be able to correctly read the data from the biosensors, particular attention needs to be given when biasing these devices. Thus, in order to correctly operate with the biosensors, the digital part of the circuit consists in a Finite State Machine (FSM) that is summarized in Fig. 5. 2) Voltage sweep: According to the writing times of the FSM, the biasing of the biosensors is performed through the proper voltage sweep with the optimal V sweep and f sweep parameters. In particular, a triangular waveform generator is used to perform the sweep. A f sweep = 7 kHz signal has been obtained using the relaxation oscillator ...
Citations
... Furthermore, the memristive biosensor presents the capability to monitor behavior of kinds of life entities, combining with the products of metabolism [13]- [15]. Recently, D. Heim et al. proposed a new instrumentation in edge computing for prostate cancer diagnostics with co-measure of Prostate Specific Antige (PSA) and its Membrane isoform (PSMA) [16], opening a promising new research line of in-memory sensing. ...
... We fix the potential on the backside of the substrate in order to avoid floating potentials during the measurement. According to a simulation model, the value of voltage gap may be affected by the input voltage [16]. Combining the schottky barrier height shown in fig 2b, the scanning voltage window is set from -3 V to +3 V. ...
The research presented in this paper draws inspiration from previous efforts aimed at replicating the functions of various solid-state memristors using a variety of materials. The memristor circuit emulator serves as a cost-effective tool for circuit designers, enabling them to experiment with the diverse electrical characteristics of corresponding solid-state memristors. This paper specifically focuses on the circuit-based emulation of Silicon Nanowire (SiNW) known for its effectiveness in bio-sensing applications. Firstly, a fully-floating memristor emulator has been presented based on a voltage differencing current conveyor (VDCC) and an operational transconductance amplifier (OTA)-controlled resistor, along with a grounded capacitance. Furthermore, the proposed memristor emulator was realized by employing integrated cells based on the discussed technology, and the simulation/experimental results are presented and analyzed. The experiments also confirmed the non-volatile behavior of the realized memristor. The results demonstrate that the real-time implementation of the proposed emulator can accurately generate hysteretic behavior in both incremental as well as decremental memristive mode. Finally, the incremental and decremental PHL (Pinched Hysteresis Loop) responses generated by the proposed emulator have been utilized to replicate the various types of memristive responses offered by SiNW by adding a simple extension to the circuit.
As established by the second law of thermodynamics, an isolated system is unable to exhibit complex behaviours. Conversely, a physical system, which interacts with the surrounding environment, may support emergent phenomena, provided some of its constitutive components are capable to amplify infinitesimal fluctuations in energy under suitable polarization, a property which is referred to as Local Activity. Local Activity is in fact a New Universal Physics Principle, which, grounded on solid theoretical foundations, enables to explain emergent phenomena in any open system, e.g. the generation of All-or-None electrical spikes in neurons, and Symmetry-Breaking Effects in biological homogeneous cellular media. The existence of solid-state memristor nano-devices, which, similarly as the sodium and potassium ion channels, may operate in the Local Activity domain under opportune bias conditions, opens up new opportunities to synthesise circuits and systems, which, operating according to biological principles, may outperform traditional computing structures in terms of time and energy efficiency. This tutorial aims to shed light on the precious role that Nonlinear Circuit and System Theory shall assume in the years to come to support the exploration of the full potential of memristor physical realizations, which clearly show signs of Local Activity while admitting a Negative Differential Resistance upon suitable DC excitation, for bio-inspired electronics.
During the past two decades, a number of two-terminal switching devices have been demonstrated in the literature. They typically exhibit hysteric behavior in the current-to-voltage characteristics. These devices have often been also referred to as memristive devices. Their capacity to switch and exhibit electrical hysteresis has made them well-suited for applications such as data storage, in-memory computing, and in-sensor computing or in-memory sensing. The aim of this perspective paper is to is twofold. Firstly, it seeks to provide a comprehensive examination of the existing research findings in the field and engage in a critical discussion regarding the potential for the development of new non-Von-Neumann computing machines that can seamlessly integrate sensing and computing within memory units. Secondly, this paper aims to demonstrate the practical application of such an innovative approach in the realm of cancer medicine. Specifically, it explores the modern concept of employing multiple cancer markers simultaneously to enhance the efficiency of diagnostic processes in cancer medicine.
Over the past decade, significant advancements have been made in the study of silicon nanowires (SiNWs). These nano-scaled devices can exhibit a memristive type of hysteresis in the current/voltage (I/V) plane that has been utilized in the biosensors leading to exceptional sensitivities up to the femto levels. Here we investigate the memristive properties of SiNW-based biosensors in their unmodified state, as well as after surface biofunctionalization with aptamers. The development of SiNWs involved a top-down nanofabrication approach, resulting in nanowires with
$100\ nm$
-wide and
$1 \ \mu m$
-long. Later, biofunctionalization was performed through controlled drop-casting. The experimental findings obtained in this study demonstrate for the first time that different SiNWs from the same fabrication batch can exhibit diverse memristive switching phenomena in the I/V plane. These phenomena encompass both volatile non-crossing memristive behavior as well as non-volatile crossing memristive responses. Furthermore, we demonstrate that the I/V hysteresis exhibited by bio-functionalized nanowires is determined by their inherent memristive characteristics and the induced capacitive effect. Drawing upon these new findings, a simple mathematical simulation model of the Memristive biosensor is developed and evaluated in SPICE.
