Electrical Detection Of Biomolecules Research Articles

Biosensors for Public Health and Environmental Monitoring: The Case for Sustainable Biosensing.

Climate change is a profound crisis that affects every aspect of life, including public health. Changes in environmental conditions can promote the spread of pathogens and the development of new mutants and strains. Early detection is essential in managing and controlling this spread and improving overall health outcomes. This perspective article introduces basic biosensing concepts and various biosensors, including electrochemical, optical, mass-based, nano biosensors, and single-molecule biosensors, as important sustainability and public health preventive tools. The discussion also includes how the sustainability of a biosensor is crucial to minimizing environmental impacts and ensuring the long-term availability of vital technologies and resources for healthcare, environmental monitoring, and beyond. One promising avenue for pathogen screening could be the electrical detection of biomolecules at the single-molecule level, and some recent developments based on single-molecule bioelectronics using the Scanning Tunneling Microscopy-assisted break junctions (STM-BJ) technique are shown here. Using this technique, biomolecules can be detected with high sensitivity, eliminating the need for amplification and cell culture steps, thereby enhancing speed and efficiency. Furthermore, the STM-BJ technique demonstrates exceptional specificity, accurately detects single-base mismatches, and exhibits a detection limit essentially at the level of individual biomolecules. Finally, a case is made here for sustainable biosensors, how they can help, the paradigm shift needed to achieve them, and some potential applications.

A Novel Dielectric Modulated Gate-Stack Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor-Based Sensor for Detecting Biomolecules

In this article, the performance of n-type junctionless (JL) double-gate (DG) MOSFET-based biosensors with and without gate stack (GS) has been studied. Here, the dielectric modulation (DM) method is applied to detect biomolecules in the cavity. The sensitivity of n-type JL-DM-DG-MOSFET and n-type JL-DM-GSDG-MOSFET-based biosensors have also been evaluated. The sensitivity (ΔVth) improved in JL-DM-GSDG MOSFET/JL-DM-DG-MOSFET-based biosensors for neutral/charged biomolecules is 116.66%/66.66% and 1165.78%/978.94%, respectively, compared with the previously reported results. The electrical detection of biomolecules is validated using the ATLAS device simulator. The noise and analog/RF parameters are compared between both biosensors. A lower threshold voltage is observed in the GSDG-MOSFET-based biosensor. The Ion/Ioff ratio is higher for DG-MOSFET-based biosensors. The proposed GSDG-MOSFET-based biosensor demonstrates higher sensitivity than the DG-MOSFET-based biosensor. The GSDG-MOSFET-based biosensor is suitable for low-power, high-speed, and high sensitivity applications.

Analytical modeling of split-gate junction-less transistor for a biosensor application

This paper represents the analytical modeling of split-gate Dielectric Modulated Junction Less Transistor (JLT) for label free electrical detection of bio molecules. Some part of the channel region is opened for providing the binding sites for the bio molecules unlike conventional MOSFET which is enclosed with the gate electrode. Due to this open area, the surface potential of this region affected by the charged and neutral bio molecules immobilized to the open region of channel. Surface potential of the channel region obtained by solving two-Dimensional Poisson's equation by potential profile having parabolic nature through channel region using technique called conformal mapping. By deriving the surface potential model, derivation of threshold model can also be done. For the detection of bio molecule, variation in to the threshold voltage due to binding of bio molecule in the gate underlap region is the sensing metric.

(Invited) Electrical Detection of Biomolecules Using Graphene-Based Devices

Label-free electrical monitoring of biorecognition events provides a promising platform, which is simpler, less expensive and requires less energy. Rapid testing of different proteins is required in various applications, including clinical diagnostics, environmental testing, food analysis, bioterrorism detection technologies, etc. Graphene, a single honeycomb-like sheet of carbon atoms, have been intensively investigated in most recent owing to its extraordinary high mobility even at room temperature [1]. Since graphene has a perfect two-dimensional structure, electrical characteristics in graphene devices are very sensitive for modulation of surface potentials in graphene channels. In this study, we have demonstrated highly sensitive electrical detection of biological molecules based on graphene devices.A monolayer graphene was obtained by mechanical cleavage of graphite or CVD-based graphene on SiO2 films. Graphene devices were fabricated by conventional lithography and lift-off method. A silicone rubber was placed on the graphene devices so that the graphene channel was immersed in a buffer solution. An Ag/AgCl reference electrode was used as the top-gated electrode to minimize environmental effects.Solution-gated graphene devices showed good transfer characteristics in buffer solution [2]. To selectively detect targets, receptors were modified on graphene channels [3-7]. For highly sensitive detection of biomolecules, small receptors such as aptamer or antigen-binding fragment (Fab) were utilized. Atomic force microscopy images revealed that receptors were successfully immobilized on the graphene channel. The receptor-modified graphene devices showed electrical detection of targets with concentration from few hundred pM to several hundred nM. Moreover, for development of highly sensitive influenza-virus sensors, glycan-modified graphene devices were also fabricated. The biological molecules were detected with high sensitivity based on graphene devices. When a different kind of receptor is functionalized on each graphene channel in the graphene-device array, many kinds of biomolecules can be electrically detected simultaneously. Therefore, the graphene-device array can be useful for the fabrication of multiplex hand-held chemical and biological sensors for home medical care. K. Novoselov, A. Geim, S. Morozov, D. Jiang, Y. Zhang, S. Dubonos, I. Grigorieva and A. Firsov, Science 306, 666 (2004). Y. Ohno, K. Maehashi, and K. Matsumoto, Biosens. Bioelectron. 26 , 1727 (2010). Y. Ohno, K. Maehashi, Y. Yamashiro, and K. Matsumoto, Nano Lett. 9, 3318 (2009). K. Maehashi, Y. Sofue, S. Okamoto, Y. Ohno, K. Inoue and K. Matsumoto, Sensors and Actuators B 187, 45 (2013). Y. Ohno, K. Maehashi, and K. Matsumoto, J. Am. Chem. Soc. 132, 18012 (2010). S. Okamoto, Y. Ohno, K. Maehashi, K. Inoue, and K. Matsumoto, Jpn. J. Appl. Phys. 51, 06FD08 (2012). N. B. M. Zaifuddin, S. Okamoto, T. Ikuta, Y. Ohno, K. Maehashi, M. Miyake, P. Greenwood, K. B. K. Teo, and K. Matsumoto, Jpn. J. Appl. Phys. 52, 06GK04 (2013).

Design Issues for Performance Enhancement in Nanostructured Silicon Oxide Biosensors: Modeling the Frequency Response

Nanostructured silicon oxide impedance biosensors with ordered nanopores promise highly sensitive and selective label-free electrical detection of biomolecules through unique frequency-dependent sensitivity characteristics. Despite these promising experimental results, the fundamental mechanisms controlling the frequency-dependent phenomena and hence the design considerations have not been explored. In this paper, we consistently model the fluid and the solid regions of the sensors and discuss the design issues with respect to the pore dimensions for enhancing the sensitivity, selectivity, and repeatability toward detection of ultralow and moderate concentration of target biomolecules. The simulation results have been validated with experiments. The results indicate that the optimal design of nanoporous silicon oxide biosensors is different from the conventional idea of increasing the surface-to-volume ratio of such sensors. Instead, the design approach is nontrivial and the optimum pore dimensions are dependent on the target biomolecule charge, concentration, and distribution. It has been observed that a figure of merit is essential to design such sensors with improved commercial viability.