Biosensor integration on Si-based devices: Feasibility studies and examples (original) (raw)
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Development of Si-based electrical biosensors: Simulations and first experimental results
Sensing and bio-sensing research, 2015
In this work, we simulated and experimentally assessed the possibility to detect, through electrical transduction, hybridization of DNA molecules on MOS-like devices, having different dielectrics: SiO 2 , Si 3 N 4 and SiO 2 /Si 3 N 4 /SiO 2 (ONO). The electrical characterization was performed after the various functionalization steps, consisting of dielectric activation, silanization, DNA spotting and anchoring, and after the hybridization process, to test the devices effectiveness as DNA recognition biosensors. The experimental results were used to validate device simulations. The comparison shows the ability to determine a priori the DNA probe density needed to maximize the response. The results confirm that the structures analyzed are sensitive to the immobilization of DNA and its hybridization.
The electrical effects of DNA as the gate electrode of MOS transistors
Proceedings. IEEE Lester Eastman Conference on High Performance Devices
The gate conductor material affects the threshold voltage of metal-oxidesemiconductor (MOS) transistors through the influence of the electrochemical work function and electric charge. Measurements of the threshold voltage from current voltage characteristics may therefore provide a method to estimate the electronic properties of biomolecules located on the gate electrode. We have deposited DNA from the corn genome onto the gate oxide of Si nMOS transistors and measured the effects on the current-voltage characteristics. We found that the DNA decreased the drain-source current compared to devices with clean gate oxides and pure buffer solutions. The threshold voltage was extracted by current-voltage measurements in the linear operating region and was found to increase by +1.9 volts after application of the DNA specimen, a value consistent with the expected negative charge density. This large change suggests that MOS devices may be useful as sensitive bioelectronic detectors.
Feasibility Studies on Si-Based Biosensors
Sensors, 2009
The aim of this paper is to summarize the efforts carried out so far in the fabrication of Si-based biosensors by a team of researchers in Catania, Italy. This work was born as a collaboration between the Catania section of the Microelectronic and Microsystem Institute (IMM) of the CNR, the Surfaces and Interfaces laboratory (SUPERLAB) of the Consorzio Catania Ricerche and two departments at the University of Catania: the Biomedical Science and the Biological Chemistry and Molecular Biology Departments. The first goal of our study was the definition and optimization of an immobilization protocol capable of bonding the biological sensing element on a Si-based surface via covalent chemical bonds. We chose SiO 2 as the anchoring surface due to its biocompatibility and extensive presence in microelectronic devices. The immobilization protocol was tested and optimized, introducing a new step, oxide activation, using techniques compatible with microelectronic processing. The importance of the added step is described by the experimental results. We also tested different biological molecule concentrations in the immobilization solutions and the effects on the immobilized layer. Finally a MOS-like structure was designed and fabricated to test an electrical transduction OPEN ACCESS Sensors 2009, 9 3470 mechanism. The results obtained so far and the possible evolution of the research field are described in this review paper.
Direct electrical detection of hybridization at DNA-modified silicon surfaces
Biosensors and Bioelectronics, 2004
Electrochemical impedance spectroscopy was used to investigate the changes in interfacial electrical properties that arise when DNA-modified Si(1 1 1) surfaces are exposed to solution-phase DNA oligonucleotides with complementary and non-complementary sequences. The n-and p-type silicon(1 1 1) samples were covalently linked to DNA molecules via direct Si-C linkages without any intervening oxide layer. Exposure to solutions containing DNA oligonucleotides with the complementary sequence produced significant changes in both real and imaginary components of the electrical impedance, while exposure to DNA with non-complementary sequences generated negligible responses. These changes in electrical properties were corroborated with fluorescence measurements and were reproduced in multiple hybridization-denaturation cycles. The ability to detect DNA hybridization is strongly frequency-dependent. Modeling of the response and comparison of results on different silicon bulk doping shows that the sensitivity to DNA hybridization arises from DNA-induced changes in the resistance of the silicon substrate and the resistance of the molecular layers.
Immobilization of DNA on CMOS compatible materials
Sensors and Actuators B: Chemical, 2003
The main interface and interconnection materials normally used in complementary metal-oxide semiconductor (CMOS) integrated circuit processing, i.e. silicon oxides and aluminum, were evaluated with regards to deoxyribonucleic acid (DNA) attachment. We investigated and quantified the influence of various techniques of fabrication of the silicon oxide on DNA binding obtained by four different biochemical processes. Regarding aluminum, we found that it only binds DNA in the presence of its natural oxide and that it is severely degraded by one of the three typical biochemical processes. Optimal process conditions for DNA binding on silicon oxides with aluminum compatibility are finally derived.
DNA On Silicon Devices: On-Chip Synthesis, Hybridization, and Charge Transfer
Angewandte Chemie International Edition, 2002
Surface-immobilized DNA has an increasing number of roles in science and technology because of the ease with which it can be manipulated chemically and enzymatically in a highly controlled manner. Complex DNA architectures [1] and the use of DNA as a scaffold for making electronic connections have been reported, and the use of DNA as a component in so-called molecular electronics has been frequently advocated. [3] Applications also include DNA microarrays for sequencing through hybridization, the study of gene expression, and even for prototype computing devices which utilize the fidelity of the hybridization reaction. [5±7] In most cases, the DNA is immobilized on glass, oxidized silicon wafers, or other insulating supports. Methods for combining DNA with electronic materials are anticipated to be increasingly important in light of the considerable interest in DNAbased nanotechnology, [1] DNA-mediated charge transfer, and DNA-based wires. For substrates such as gold [9] or Si, where there is the possibility of charge transfer through the DNA to the surface, immobilization has relied upon the attachment of presynthesized strands. However, to date there has been no demonstration of the use of automated solidphase DNA synthesis nor charge transfer through DNAbased assemblies at a semiconductor. For many proposed applications the ability to combine microelectronic processing techniques, for example, photolithography and micromachining, with automated chemical synthesis has clear advantages. Herein we outline a method that enables the straightforward integration of DNA technology with microelectronics.
Applied Physics Letters, 2012
In this work, metal-oxide-semiconductor (MOS)-like sensors in which deoxyribonucleic acid (DNA) strands are covalently immobilized either on Si oxide or on a gold surface were electrically characterized. Si oxide fabrication process allowed us to have a surface insensitive to the solution pH. A significant shift in the flat band voltage was measured after single strand DNA immobilization (þ0.47 6 0.04 V) and after the complementary strand binding (þ0.07 6 0.02 V). The results show that DNA sensing can be performed using a MOS structure which can be easily integrated in a more complex design, thus avoiding the problems related to the integration of micro-electrochemical cells. V C 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4747452\]
Electrical Characterization of Biological Molecules Deposition in MOS Capacitors
Sensor Letters, 2008
The aim of this work was the electrical characterization of biological molecules covalently immo bilized on the dielectric of a MOS-like structure. The experimental protocol to bond the biological molecules on Si0 2 lies in: oxide activation, silanization, linker molecule deposition, biological molecule bonding; Both an enzyme, the glucose oxidase (GOx), and single-stranded oligonu cleotides (ssDNA) were selected as biological molecules. The effectiveness of the immobilization procedure was tested by X-ray Photoelectron spectroscopy. The electrical characterization was car ried out on reference and fully processed samples as a function of the electrolyte pH, from 3 to 8, and of measurement time, up to 200 s. The oxide does not experience any aging during the mea surement sets for voltages up to ± 3 V. GOx deposition produces a shift of about -0.7 ± 0.04 V in the V FB , suggesting the molecule has a positive charge when anchored to the oxide layer. On the other hand, ssDNA deposition causes a positive shift, below 0.3 V, as expected due to the DNA negative charge in solution. The hybridization process causes a further shift in the V FB above 0.4 V, well above the experimental errors, confirming the sensitivity of this device to monitor the hybridization. Our preliminary data show a potential for the development of MOS-based biosensors.
Silicon nitride surfaces as active substrate for electrical DNA biosensors
Sensors and Actuators B: Chemical, 2017
Innovative study on Si3N4 surfaces for DNA electrical detection Optimized DNA grafting protocol on Si3N4 surfaces for biodetection Fully Si3N4 surface characterization by contact angle, ellipsometry, Atomic Force Microscopy, and Transmission Electron Microscopy. Surface and optical comparison between Si3N4 and SiO2 surface (reference material for DNA grafting) DNA electrical detection (C-V curves) on MIS-like capacitors VFB shift value of 0.4V upon hybridization with perfect match VFB shift value of 0.8V upon hybridization with PCR product Correlation between DNA number of bases and C-V shift
ISFET Based DNA Sensor: Current-Voltage Characteristic and Sensitivity to DNA Molecules
Open Journal of Biophysics, 2019
Dependency of both source-drain current and current sensitivity of nanosize ISFET biosensor vs. concentration of DNA molecules in aqueous solution theoretically is investigated. In calculations it is carried out effects concerning charge carriers distribution in current channel and concerning carriers' mobility behavior in high electrical fields in the channel. The influence of DNA molecules on the work of ISFET biosensors is manifested by a change in the magnitude of the gate surface charge. Starting with fairly low concentrations of DNA, ISFET sensors respond to the presence of DNA molecules in an aqueous solution which is manifested by modulation of channel conductance and therefore the source-drain current changes of the field-effect transistor. It is shown that the current sensitivity with respect to concentration of DNA molecules linearly depends on the source-drain voltage and reaches high values.