Analytical Modelling of Dielectric Modulated Negative Capacitance MoS2-FET for Biosensor Application

In this paper, a dielectric modulated negative capacitance (NC)-MoS₂ field effect transistor (FET)-based biosensor is proposed for label-free detection of biomolecules such as enzymes, proteins, DNA, etc. Various reports present experimental demonstration and modelling of NC-MoS₂ FET, but it is never utilized as a dielectric modulated biosensor. Therefore, in this work, the modelling, characterization and sensitivity analysis of dielectric modulated NC-MoS₂ FET is focussed. For immobilization of biomolecules, a nanocavity is formed below the gate by etching some portion of the gate oxide material. The immobilization of biomolecules in the cavity leads to a variation of different electrostatic properties such as surface potential, threshold voltage, drain current, and subthreshold-swing (SS) which can be utilized as sensing parameters. An analytical model for the proposed biosensor is also developed in the subthreshold region by considering the properties of two-dimensional (2D) ferroelectric materials and benchmarked with TCAD device simulations. The effect of change of gate length and doping concentration on different electrical properties is also analysed to estimate the optimum value of channel doping. The results prove that the proposed device can be used for next-generation low power label-free biosensor which shows enhanced sensitivity as compared to traditional FET-based biosensors.

Analytical Modelling of Dielectric Modulated Negative Capacitance MoS2-FET for Biosensor Application

In this paper, a dielectric modulated negative capacitance (NC)-MoS₂ field effect transistor (FET)-based biosensor is proposed for label-free detection of biomolecules such as enzymes, proteins, DNA, etc. Various reports present experimental demonstration and modelling of NC-MoS₂ FET, but it is never utilized as a dielectric modulated biosensor. Therefore, in this work, the modelling, characterization and sensitivity analysis of dielectric modulated NC-MoS₂ FET is focussed. For immobilization of biomolecules, a nanocavity is formed below the gate by etching some portion of the gate oxide material. The immobilization of biomolecules in the cavity leads to a variation of different electrostatic properties such as surface potential, threshold voltage, drain current, and subthreshold-swing (SS) which can be utilized as sensing parameters. An analytical model for the proposed biosensor is also developed in the subthreshold region by considering the properties of two-dimensional (2D) ferroelectric materials and benchmarked with TCAD device simulations. The effect of change of gate length and doping concentration on different electrical properties is also analysed to estimate the optimum value of channel doping. The results prove that the proposed device can be used for next-generation low power label-free biosensor which shows enhanced sensitivity as compared to traditional FET-based biosensors.

Biosensors Preliminary Concepts and Its Principles with Applications in the Engineering Perspective

Biosensor is rapid detection of any infectious disease at the early stages is critical for supporting public health and ensuring effective healthcare outcomes. A timely and accurate diagnosis of a disease is necessary for an effective medical response where is biosensor takes place. The design and development of biosensors have taken a centre stage for researchers or scientists in the recent decade owing to the wide range of biosensor applications, such as health care and disease diagnosis, environmental monitoring, water and food quality monitoring, and drug delivery and lately it shown great potential for use in tissue engineering and regenerative medicine. Biosensors are ideally suited to many diagnostic and real-time detection problems due to their use of biological molecules, tissues, and cells, and their high capacity for precision and accuracy promises to continue this trend. Biosensors will become even more widespread and essential to the industrial, agricultural, scientific, and health care as biotechnology tools advance to allow additional biosensor growth. Keywords: biosensor, biosensor historical perspective, biosensor parameters, biosensor application.

Hexaferrocenium tri[hexa(isothiocyanato)iron(III)] trihydroxonium complex as a new DNA intercalator for electrochemical DNA biosensor

Ferrocene or ferrocenium has been widely studied in the field of organometallic complexes because of its stable thermodynamic, kinetic and redox properties. Novel hexaferrocenium tri[hexa(isothiocyanato)iron(III)]trihydroxonium (HexaFc) complex was the product from the reaction of ferrocene, maleic acid and ammonium thiocyanate and was confirmed by elemental analysis CHNS, FTIR and single crystal X-ray crystallography. In this study, HexaFc was used for the first time as an electroactive indicator for porcine DNA biosensor. The UV–Vis DNA titrations with this compound showed hypochromism and redshift at 250 nm with increasing DNA concentrations. The binding constant (Kb) for HexaFc complex towards CT-DNA (calf-thymus DNA) was 3.1 × 104 M−1, indicated intercalator behaviour of the complex. To test the usefulness of this complex for DNA biosensor application, a porcine DNA biosensor was constructed. The recognition probes were covalently immobilised onto silica nanospheres (SiNSs) via glutaraldehyde linker on a screen-printed electrode (SPE). After intercalation with the HexaFc complex, the response of the biosensor to the complementary porcine DNA was measured using differential pulse voltammetry. The DNA biosensor demonstrated a linear response range to the complementary porcine DNA from 1 × 10−6 to 1 × 10−3 µM (R2 = 0.9642) with a limit detection of 4.83 × 10−8 µM and the response was stable up to 23 days of storage at 4 °C with 86% of its initial response. The results indicated that HexaFc complex is a feasible indicator for the DNA hybridisation without the use of a chemical label for the detection of porcine DNA.