Detection Of Biomolecules Research Articles

Isolation of novel fluorogenic RNA aptamers via in vitro compartmentalization using microbead-display libraries

Fluorogenic RNA aptamers, which specifically bind to fluorogens and dramatically enhance their fluorescence, are valuable for imaging and detecting RNAs and metabolites in living cells. Most fluorogenic RNA aptamers have been identified and engineered through iterative rounds of in vitro selection based on their binding to target fluorogens. While such selection is an efficient approach for generating RNA aptamers, it is less efficient for isolating fluorogenic aptamers because it does not directly screen for fluorogenic properties. In this study, we combined a fluorescence-based in vitro selection technique using water-in-oil microdroplets with an affinity-based selection technique to obtain fluorogenic RNA aptamers. This approach allowed us to identify novel fluorogenic aptamers for a biotin-modified thiazole orange derivative. Our results demonstrate that our approach can expand the diversity of fluorogenic RNA aptamers, thus leading to new applications for the imaging and detection of biomolecules.

Label -free measuring biomolecular interactions using plasmonic metasurfaces with dual bands based on surface lattice resonances in the mid-infrared range

Mid-infrared plasmonic metasurfaces are remarkable platforms for chemical-specific detection and dynamic monitoring of biomolecules. This study uses surface-enhanced infrared absorption (SEIRA) spectroscopy by applying plasmonic metasurfaces for label-free and real-time monitoring of biomolecular interactions. SEIRA devices based on geometric combinations of two types of square arrays with different Au microdots require the use of new dual-resonant plasmonic metasurfaces. Resonant matching between the plasmonic and molecular vibrational modes can be realized through the controlled microdot dimensions and periodicity of the array. Plasmonic surface lattice resonances contribute to this optical tuning, enabling simultaneous observations of SEIRA-enhanced methyl and amide bands. The electric fields on mixed arrays were strongly confined to approximately 100 nm, enabling high SEIRA performance and single molecule detection. Moreover, the SEIRA device no longer needed in-plane polarization control of IR light, enhancing sensing detection’s robustness and stability. Finally, the in situ real-time monitoring of biomolecular interactions between protein A and immunoglobulin, which provides remarkable changes in the intensity and vibrational features of SEIRA absorbance, is reported. Dynamic SEIRA measurements using molecular vibrations as self-biomarkers helped in identifying the kinetic parameters required for important affinity metrics of biomolecular interactions.

Efficient colorimetric point-of-care detection and imaging of multiple biomolecules utilizing photonic liquid crystal composite on gold nanoisland thin films for label-free sensing

Efficient colorimetric point-of-care detection and imaging of multiple biomolecules utilizing photonic liquid crystal composite on gold nanoisland thin films for label-free sensing

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.

MeNPs-PEDOT Composite-Based Detection Platforms for Epinephrine and Quercetin.

The development of low-cost, sensitive, and simple analytical tools for biomolecule detection in health status monitoring is nowadays a growing research topic. Sensing platforms integrating nanocomposite materials as recognition elements in the monitoring of various biomolecules and biomarkers are addressing this challenging objective. Herein, we have developed electrochemical sensing platforms by means of a novel fabrication procedure for biomolecule detection. The platforms are based on commercially available low-cost conductive substrates like glassy carbon and/or screen-printed carbon electrodes selectively functionalized with nanocomposite materials composed of Ag and Au metallic nanoparticles and an organic polymer, poly(3,4-ethylenedioxythiophene). The novel fabrication method made use of alternating currents with controlled amplitude and frequency. The frequency of the applied alternating current was 100 mHz for the polymer deposition, while a frequency value of 50 mHz was used for the in situ electrodeposition of Ag and Au nanoparticles. The selected frequency values ensured the successful preparation of the composite materials. The use of readily available composite materials is intended to produce cost-effective analytical tools. The judicious modification of the organic conductive matrix by various metallic nanoparticles, such as Ag and Au, extends the potential applications of the sensing platform toward a range of biomolecules like quercetin and epinephrine, chosen as benchmark analytes for proof-of-concept antioxidant and neurotransmitter detection. The sensing platforms were tested successfully for quercetin and epinephrine determination on synthetic and real samples. Wide linear response ranges and low limit-of-detection values were obtained for epinephrine and quercetin detection.

A high Q-factor evanescent field fiber sensor coated with C-MWCNT for label-free HPV determination

A high Q-factor evanescent field fiber sensor is designed based on a fiber Bragg grating (FBG) coated with carboxylic multi-walled carbon nanotubes (C-MWCNT). In a high-reflectivity FBG, multiple cladding modes are stimulated as the forward-moving guided mode within the core of the multimode fiber is coupled to the FBG’s reverse-moving guided mode within the cladding. Our evanescent field fiber sensor is highly sensitive to the refractive index without altering the architecture of fiber or deviating from the conventional process of fabricating fiber gratings. The proposed sensor exhibits a full-width at half maximum (FWHM) of 78 pm and a Q-factor of 1.9 × 104 for its standard cladding-mode resonance, outperforming the majority of reported evanescent field fiber sensors in these parameters. Furthermore, by coating C-MWCNT on the fiber sensing surface, our sensor has been demonstrated to combine multiple functions into one, such as label-free determination of human papilloma virus (HPV) DNA sequences, the measurement of different concentrations, and mispairing discrimination. The sensor design put forward offers a compelling technique within the realm of optical fiber sensing for refractive index and label-free biomolecule detection.

Ti3C2Tx Coated with TiO2 Nanosheets for the Simultaneous Detection of Ascorbic Acid, Dopamine and Uric Acid.

Two-dimensional MXenes have become an important material for electrochemical sensing of biomolecules due to their excellent electric properties, large surface area and hydrophilicity. However, the simultaneous detection of multiple biomolecules using MXene-based electrodes is still a challenge. Here, a simple solvothermal process was used to synthesis the Ti3C2Tx coated with TiO2 nanosheets (Ti3C2Tx@TiO2 NSs). The surface modification of TiO2 NSs on Ti3C2Tx can effectively reduce the self-accumulation of Ti3C2Tx and improve stability. Glassy carbon electrode was modified by Ti3C2Tx@TiO2 NSs (Ti3C2Tx@TiO2 NSs/GCE) and was able simultaneously to detect dopamine (DA), ascorbic acid (AA) and uric acid (UA). Under concentrations ranging from 200 to 1000 μM, 40 to 300 μM and 50 to 400 μM, the limit of detection (LOD) is 2.91 μM, 0.19 μM and 0.25 μM for AA, DA and UA, respectively. Furthermore, Ti3C2Tx@TiO2 NSs/GCE demonstrated remarkable stability and reliable reproducibility for the detection of AA/DA/UA.

A unique wheel-shaped exposed core LSPR-PCF sensor for dual-peak sensing: Applications in the optical communication bands, M-IR region and biosensing

Photonic Crystal Fibers (PCF) effectiveness in practice decreases if the fabrication of the sensor becomes too complex. Keeping this in mind, we propose a one-of-a-kind wheel shaped PCF sensor with an exposed core containing only three air holes with exceptional sensing features. The sensor is equipped with dual plasmonic layers, Indium Tin Oxide (ITO, 10 % wt) and silver (Ag) with a coating of TiO2 to enhance the sensing capabilities and provide protection against oxidation. The sensor's distinctive configuration enables it to exhibit two distinct peaks within a range of refractive index from 1.32 to 1.38 for y-polarization and from 1.35 to 1.38 for x-polarization. The sensor specifications have been optimized to achieve the maximum levels of wavelength sensitivity (WS) and double peak shift sensitivity (DPSS). The sensor portrays a WS of 50,652 nm/RIU and the highest DPSS ever recorded, measuring 50,000 nm/RIU. Additionally, the sensor exhibits a significantly high scale of amplitude sensitivity (AS) of 1668.34 RIU−1 which is a very remarkable value considering silver as plasmonic material along with an outstanding figure of merit (FOM) of 1017.11 RIU−1. In addition, our sensor is able to manifest resolutions in the order of 10−6, demonstrating a resolution of 5.94 × 10−6 RIU with the deployment of amplitude interrogation method and 1.97 × 10−6 RIU with the wavelength interrogation method. The design spans an extensive spectrum, covering ultraviolet to mid-infrared wavelengths, enabling detection of biomolecules and biochemicals, along with operation in the optical communication band.

Study on Synthesis and Characterization of Metal Nanoparticles for Biomedical Applications

In this research paper, I have thoroughly described about the topic “Study on Synthesis and Characterization of Metal Nanoparticles for Biomedical Applications.” Metal nanoparticles have emerged as promising candidates for a myriad of biomedical applications due to their unique physicochemical properties, offering a wide array of opportunities for innovation in healthcare. This abstract discusses metal nanoparticle creation, characterization, and biomedical applications. Chemical reduction, green synthesis, physical deposition, and biological methods allow fine nanoparticle size, shape, and composition control for biomedical applications. TEM, DLS, XRD, UV-Vis, FTIR, SEM, and TGA reveal metal nanoparticles' structural, chemical, and optical properties. Metal nanoparticles are used in medication delivery, imaging contrast, targeted therapy, and diagnostics. Their small size, large surface area-to-volume ratio, and tunable optical properties make them suitable for drug delivery, where they can encapsulate and release therapeutic substances at precise body regions. Metal nanoparticles also improve illness identification and monitoring in MRI, CT, and fluorescence imaging by acting as contrast agents. They provide innovative cancer and microbial infection treatments due to their photothermal and antibacterial characteristics. Metal nanoparticles also find utility in biosensing applications, facilitating the detection of biomolecules and disease biomarkers with high sensitivity and specificity. Overall, the synthesis and characterization of metal nanoparticles represent a vibrant area of research with significant implications for advancing healthcare technologies, offering versatile platforms for addressing key challenges in diagnostics, therapeutics, and imaging in biomedicine.

Recent Progress of Fluorescent Carbon Dots and Graphene Quantum Dots for Biosensors: Synthesis of Solution Methods and their Medical Applications.

In the fields of health and biology, fluorescent nanomaterials have emerged as highly potential and very useful candidates for use in biosensor applications. These typical highly powerful nanomaterials are carbon dots (CDs) and graphene quantum dots (GQDs) among many other metallic nanomaterials. In the context of medical biosensors, this review article investigates the techniques of synthesis, and many uses of these nanomaterials, the obstacles that they face, and the potential for their future. We cover the significance of fluorescent nanomaterials, their use in the medical field, as well as the several techniques of synthesis for CDs and GQDs, including ultrasonication, hydrothermal, electrochemical method, surface modification, and solvothermal. In addition, we also discuss their biomedical applications, which include biomolecule detection, disease diagnosis and examine the obstacles and prospective possibilities for development of ultra-bright, ultra-sensitive, and selective biosensors for use in in-vivo research.Fluorescent carbon dots and graphene quantum dots is synthesized by using several types of raw material and methods. These Carbon dots and graphene quantum dots are used in the medical field includes detection of biomaterials, detection of cancer, virus and mutation in DNA.

Sensitivity analysis of bi-metal stacked-gate-oxide hetero-juncture tunnel fet with Si0.6Ge0.4 source biosensor considering non-ideal factors.

This article provides insights in designing a dielectrically modulated biosensor by adopting high-k stacked gate oxide proposition in a bi-metal hetero-juncture Tunnel Field Effect Transistor (BM-SO-HTFET) with Si0.6Ge0.4 source. The integrated effect of heterojunction and stacked gate oxide leads to enhanced electrical performance of the proposed device in terms of carrier mobility and suppressed leakage current. Nano-cavity engraved beneath the bi-metal gate structure across the source/channel end acts the binding site of the biomolecules to be detected. This Configuration leads to improved control of biomolecules over source/channel tunnelling rate and the same is reflected in the sensing ability of the device while extracting the ON current sensitivity (SON) of the sensor. The reported biosensor is simulated using Silvaco ATLAS calibrated simulation framework. The analysis of the device sensitivity is carried out varying dielectric constants (k) of various biomolecules, both neutral as well as charged. Our study reveals that BM-SO-HTFET with Ge mole fraction composition x = 0.4 exhibits sensitivity as high as 4.1 × 1010 for neutral biomolecules and 3.2 × 1011 for positively charged biomolecules with k = 12. Furthermore, a transient response profile for the drain current with various biomolecules is explored to determine the varying settling time. From the simulation results, it is noted that BM-SO-HTFET exhibits ON current sensitivity of 4.1 × 1010 and 3.2 × 1011 for neutral and charged biomolecules respectively. In addition to this, for highly sensitive and real time detection of biomolecules, the impact of temperature and certain non-ideal factors drifting from ideal case of fully filled cavity have also been considered to analyze its optimum sensing performance.

Spectral-fluorescent study of substituted trimethine cyanine dyes in solutions and in complexes with DNA. Effects of aggregation, moderate heating, and decreasing pH

Trimethine cyanine dyes are widely used as probes for the detection, study and quantification of biomolecules. In particular, cationic trimethine cyanines noncovalently interact with DNA with growing fluorescence. However, their use is often limited by the tendency to self-association – to the formation of aggregates. Disubstituted trimethine cyanines with hydrophobic substituents are especially prone to aggregation. In this work, we studied the interaction of a number of substituted trimethine cyanines with DNA (in aqueous buffer solutions) and showed that their aggregation strongly interfered with their use as fluorescent probes for DNA. To eliminate this drawback, preliminary heating of dye solutions with DNA to 60–70 °C was used, followed by cooling to room temperature. Compared to the experiments without heating, an increase in the dye fluorescence intensity was observed due to the partial thermal decomposition of the aggregates and the interaction of the resulting monomers with DNA. To decompose aggregates, another method was also used – protonation of the dyes with amino substituents in buffer solutions with pH 5.0, which also led to growing the dye fluorescence intensity in the presence of DNA. Complexes of the dyes with DNA were modeled using molecular docking. Effective binding constants of the dyes to DNA and detection limits when using the dyes as probes for DNA (LOD and LOQ) were determined. It is shown that dye 3 with heating in neutral buffer and dye 1 in acidic buffer may be recommended as sensitive probes for DNA. It is concluded that the method of preliminary heating may be applied to dyes prone to aggregation, for improving their properties as biomolecular probes. Another possible means to reduce the interfering effects of dye aggregates is to use easily protonated dyes (with amino substituents) in slightly acidic media.

Aptamer responsive DNA Functionalized hydrogels electrochemiluminescence biosensor for the detection of adenosine triphosphate

DNA hydrogel represents a noteworthy biomaterial. The preparation of biosensors by combining DNA hydrogel with electrochemiluminescence can simplify the modification process and raise the experimental efficiency. In this study, an electrochemiluminescence (ECL) biosensor based on DNA hydrogel was fabricated to detect adenosine triphosphate (ATP) simply and quickly. CdTe–Ru@SiO2 nanospheres capable of ECL resonance energy transfer (RET) were synthesized and encapsulated CdTe–Ru@SiO2 in the DNA hydrogel to provide strong and stable ECL signals. DNA hydrogel avoided the labeling of ECL signal molecules. The aptamer of ATP as the linker of the hydrogel for the specificity of ATP detection. The cross-linked structure of the aptamer and the polymer chains was opened by ATP, and then the decomposition of the DNA hydrogel initiated the escape of CdTe–Ru@SiO2 to generate an ECL signal. The designed biosensor detected ATP without too much modification and complex experimental steps on the electrode surface, with good specificity and stability, and a wide linear range. The detection range was 10–5000 nM, and the detection limit was 6.68 nM (S/N = 3). The combination of DNA hydrogel and ECL biosensor provided a new way for clinical detection of ATP and other biomolecule.

Sensitivity enhancement using triple metal gate work function engineering of junctionless cylindrical gate all around SiNW MOSFET based biosensor for neutral biomolecule species detection for upcoming sub 14 nm technology node

In the present work Dielectric Modulation (DM) technique along with Triple Metal (TM) gate engineering has been used for the junctionless (JL) cylindrical gate all around (CGAA) Si nanowire (NW) MOSFET based biosensor for label free electrical detection of neutral biomolecules species like Uricase, Streptavidin, Protein, Biotin, ChOx (choline oxidase), and APTES etc. For this device, the Drift Diffusion approach has been used along with self-consistent solution of Schrodinger’s equation with Poisson’s equation. For the biomolecule immobilization, a nanogap cavity region is formed in the JL SiNW MOSFET by etching gate oxide layer above the SiO2 interfacial layer. The change in the drain current (ID), threshold voltage (Vth), off-current sensitivity (SIoff), threshold voltage sensitivity (SVth) and Ion/Ioff current ratio of the device have been considered as the sensing parameters for detection of biomolecules under dry environment condition. In present work a new sensing metric of sensing of biomolecules – DIBL has been added which has never been reported in literature. In this work for JL SiNW, sensitivity metrics like smaller DIBL ∼50.47 mV/V, higher SIoff9.33×105, higher SVth28.72, nearly ideal subthreshold slope (SS) ∼60 mV/dec, and higher Ion/Ioff current ratio ∼9.01 × 1012 have been obtained in comparison to available literature results.

Au-Ag nano-garlands as a versatile SERS substrate: Two-step synthesis realizes the growth of petal-shaped branches on hollow Au-Ag nanoshells

In this work, we synthesized Au-Ag alloy nano-garlands with multiple petal-like branches and internal cavities in two steps. First, we etched silver nanospheres with HAuCl4 to obtain Au-Ag alloy nanoshells with different shell layer thicknesses and hollow core sizes. After that, based on different nanoshells, 4-NTP was used as a shape-directing agent, HAuCl4 and AgNO3 as precursor raw materials, and AA as a reducing agent for the growth of petals to form Au-Ag bimetallic nano-garlands with multi-branching structure. The regulation of the branching morphology of the nano-garlands could be achieved by changing the amounts of 4-NTP and HAuCl4. The SERS activity of the nano-garlands could be further improved by changing the AA concentration, the size of nanoshells, and the Au/Ag ratio of the precursor raw materials. Because the bimetallic nano-garlands have hollow cavities and petal-like branches, there are couplings between the cavities and the branches, between the adjacent branches, and between the metals inside and outside of the cores, which can achieve a good enhancement of SERS. The highest SERS enhancement factor of Au-Ag bimetallic nano-garlands can reach 4.47×108, which can be used as a good candidate for SERS substrate for the trace detection of biomolecules, pesticides, and other substances.

Sparfloxacin/Gold Nanoparticles Modified Electrochemical Sensor for the Determination of Dopamine

Background: The development of facile, reliable, and sensitive electrochemical sensors for neurotransmitter detection is of utmost importance in biomedical research. Objectives: In this study, we proposed a novel approach for the synthesis of gold nanoparticles (AuNPs) using sparfloxacin as a reducing and stabilizing agent and further utilized as-prepared AuNPs for the construction of an electrochemical sensor to detect dopamine. Methods: The synthesis of AuNPs was achieved through a simple method where sparfloxacin acted as both a reducing and stabilizing agent. The AuNPs were investigated by using UV-visible spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), elemental mapping (Emap), and X-ray diffraction (XRD). Results: The synthesised AuNPs were used to develop an electrochemical sensor for the detection of dopamine molecules. The fabricated electrochemical sensor demonstrated remarkable sensitivity and selectivity toward dopamine sensing. This sensor exhibited a good linear detection of dopamine in micromolar concentrations. Moreover, the sensor showed excellent stability and reproducibility. Conclusion: This novel electrochemical sensor holds significant potential for practical applications in neuroscience and clinical diagnosis, offering a rapid and sensitive method for dopamine detection. The utilization of sparfloxacin/AuNPs provides a promising avenue for the development of advanced electrochemical sensors with enhanced performance and wider applications in the detection of other neurotransmitters and biomolecules.

Advancing MicroRNA Detection: Enhanced Biotin-Streptavidin Dual-Mode Phase Imaging Surface Plasmon Resonance Aptasensor.

MicroRNAs (miRNAs) are novel tumor biomarkers owing to their important physiological functions in cell communication and the progression of multiple diseases. Due to the small molecular weight, short sequence length, and low concentration levels of miRNA, miRNA detection presents substantial challenges, requiring the advancement of more refined and sensitive techniques. There is an urgent demand for the development of a rapid, user-friendly, and sensitive miRNA analysis method. Here, we developed an enhanced biotin-streptavidin dual-mode phase imaging surface plasmon resonance (PI-SPR) aptasensor for sensitive and rapid detection of miRNA. Initially, we evaluated the linear sensing range for miRNA detection across two distinct sensing modalities and investigated the physical factors that influence the sensing signal in the aptamer-miRNA interaction within the PI-SPR aptasensor. Then, an enhanced biotin-streptavidin amplification strategy was introduced in the PI-SPR aptasensor, which effectively reduced the nonspecific adsorption by 20% and improved the limit of detection by 548 times. Furthermore, we have produced three types of tumor marker chips, which utilize the rapid sensing mode (less than 2 min) of PI-SPR aptasensor to achieve simultaneous detection of multiple miRNA markers in the serum from clinical cancer patients. This work not only developed a new approach to detect miRNA in different application scenarios but also provided a new reference for the application of the biotin-streptavidin amplification system in the detection of other small biomolecules.

Based ATP-gating mechanism for detection of alkaline phosphatase in single-glass micropipettes functionalized by three-dimensional DNA network.

The construction of gating system in artificial channels is a cutting-edge research direction in understanding biological process and application sensing. Here, by mimicking the gating system, we report a device that easily synthesized single-glass micropipettes functionalized by three-dimensional (3D) DNA network, which triggers the gating mechanism for the detection of biomolecules. Based on this strategy, the gating mechanism shows that single-glass micropipette assembled 3D DNA network is in the "OFF" state, and after collapsing in the presence of ATP, they are in the "ON" state, at which point they exhibit asymmetric response times. In the "ON" process of the gating mechanism, the ascorbic acid phosphate (AAP) can be encapsulated by a 3D DNA network and released in the presence of adenosine triphosphate (ATP), which initiates a catalyzed cascade reaction under the influence of alkaline phosphatase (ALP). Ultimately, the detection of ALP can be responded to form the fluorescence signal generated by terephthalic acid that has captured hydroxyl radicals, which has a detection range of 0-250mU/mL and a limit of detection of 50mU/mL. This work provides a brand-new way and application direction for research of gating mechanism.

A negative capacitance field effect transistor with a modified gate stack and drain-side cavity for label-free biosensing

Dielectrically modulated (DM) negative capacitance field effect transistor (NCFET)-based label-free biosensors have emerged as promising devices for accurate detection of various biomolecules, where the sensitivity of DM architectures strongly depends on the sensing mechanism as well as on the size of the nanocavity. Therefore, to achieve higher sensitivity along with reduced fabrication complexity, we propose to utilize a pre-existing drain-side spacer region as a nanocavity, in a fully depleted silicon-on-insulator-based NCFET architecture. The ferroelectric (FE) layer in the metal-ferroelectric-insulator-semiconductor configuration meaningfully alters the impact of the drain’s electric field on the source-side electrostatics, which results in higher sensitivity. Having quantified the sensitivity of an FE-dielectric (FE-DE) gate-stack-based NCFET biosensor, we now propose to include a paraelectric (PE) layer between the FE and DE materials, thus modifying the gate stack from FE-DE to FE-PE-DE with an equivalent negative capacitance seen from both stacks; here, a remarkable improvement is seen in the FE-PE-DE gate-stack-based NCFET, with nearly identical linearity performance, as seen from the high Pearson’s coefficient value ( r2⩾ 0.9). Therefore, to illustrate the efficacy of the proposed sensing mechanism and the modified gate stack (FE-PE-DE), DE constant ( kBio ) values in the range of kBio = 4.5 to kBio = 75.99 are considered. Finally, the effect of scaling the channel length ( Lg ) on the sensitivity of the FE-PE-DE NCFET device is shown, and a high value, particularly at lower permittivity, demonstrates the versatility and wide applicability of the proposed NCFET biosensor.

Design and sensitivity analysis of GAA nanowire dopingless FET based label free biosensor

This paper proposes a highly sensitive nanoscale label-free biosensor upon charge plasma based gate-all-around nanowire dopingless field effect transistor (GAA NW DL FET Biosensor) for the detection of biomolecules. The proposed sensor device structure employs charge plasma and dopingless approaches to eliminate the requirement for doping. The thermionic emission of FET structures increases the device’s current sensitivity (SI) for various targeted biomolecules introduced through the nanocavity created at the source side/metal of the proposed biosensor. To test the significant sensing performance of the device proposed herein, the biomolecules streptavidin with a dielectric constant (K) of 2.1, 3-aminopropyltriethoxysilane (APTES) with a K value of 3.57, and protein with a K value of 8 are utilized. The proposed sensor resulted in drain current sensitivity as high as 1.4 of protein biomolecule. An extensive analysis was performed to evaluate the efficiency of the proposed sensor with process-related issues such as cavity length variations ranging from 21 nm to 3 nm and real-time related issues such as fill factor variations ranging from 20% to 100% and interface charges for the targeted biomolecules, and their sensitivity parameters were investigated, demonstrating the promising features of GAA NW DL FET biosensor as an ultrasensitive biosensor for clinical applications.