Design of nano webs for hybrid sensor devices

2014 ◽  
Vol 1690 ◽  
Author(s):  
Nandhinee Radha Shanmugam ◽  
Milin Nilesh Rana ◽  
Shalini Prasad
Keyword(s):  
Surface Charge ◽  
Carrier Transport ◽  
Troponin T ◽  
Drain Current ◽  
Polymer Nanocomposite ◽  
Building Blocks ◽  
Electrical Signal ◽  
Detection Sensitivity ◽  
Current Response ◽  
Detection Of Biomolecules

ABSTRACTHybrid organic/inorganic nanostructures are engineered to function as two terminal devices with enhanced functionality. The devices are the building blocks for designing hybrid organic/inorganic circuits in the nanoscale. In our work, we have demonstrated the sensing capabilities of polymer nanocomposite thin films for designing nanoweb devices towards detection of biomolecules. Biomolecules with surface charge such as troponin-T were detected on this device by interfacing them with the polymer/metal composites. The change in electrical properties due to modulation in charge transport at the crossbar junction was identified as the measured electrical signal for designing switch based sensors. Nanotextured surface offers strong charge carrier transport and hence enhances the strength of the detected signal. The antibodyantigen interactions at the junction effectively modulate the charge transfer kinetics and modify the junction characteristics due to the surface potential associated with the organic molecules. The net change in surface charge can be measured either as changes in the diode current in the two terminal configuration or as changes in the source- drain current in the three terminal configuration. Detection sensitivity in the order of pg/mL was targeted by measuring the voltammetric current response (in microamperes).

scholarly journals Magnetic Assembly Route to Construct Reproducible and Recyclable SERS Substrate

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Bingfang Zou ◽  
Chunyu Niu ◽  
Ming Ma ◽  
Lu Zhao ◽  
Yongqiang Wang
Keyword(s):  
Noble Metal ◽  
Reaction System ◽  
Practical Interest ◽  
Building Blocks ◽  
Detection Sensitivity ◽  
Sers Substrate ◽  
Magnetic Assembly ◽  
Surface Enhanced Raman ◽  
Signal Sensitivity ◽  
Uniform Array

AbstractThe fabrication of a uniform array film through assembly of colloidal building blocks is of practical interest for the integrated individual and collective functions. Here, a magnetic assembly route was put forward to organize monodisperse noble metal microspheres into a uniform array film for surface-enhanced Raman scattering (SERS) application, which demonstrated the integrated signal sensitivity of single noble metal microspheres and reproducibility of their assembled uniform array film. For this purpose, monodisperse multifunctional Fe3O4@SiO2@TiO2@Ag (FOSTA) colloidal microspheres as building blocks were successfully synthesized through a homemade ultrasonic-assisted reaction system. When used in SERS test, these multifunctional microspheres could firstly bind the analyte (R6G) from solution and then assembled into a uniform film under an external magnetic field, which exhibited high SERS detection sensitivity with good reproducibility. In addition, due to the TiO2 interlayer in FOSTA colloidal microspheres, the building blocks could be recycled and self cleaned through photocatalytic degradation of the adsorbed analyte for recycling SERS application.

scholarly journals A Review on Biosensors and Recent Development of Nanostructured Materials-Enabled Biosensors

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1109
Author(s):  
Varnakavi. Naresh ◽  
Nohyun Lee
Keyword(s):  
High Surface ◽  
Three Dimensional ◽  
Biological Response ◽  
Volume Ratio ◽  
Recent Decade ◽  
Disease Diagnosis ◽  
Electrical Signal ◽  
Detection Sensitivity ◽  
Wide Range ◽  
Color Tunability

A biosensor is an integrated receptor-transducer device, which can convert a biological response into an electrical signal. The design and development of biosensors have taken a center 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. The main challenges involved in the biosensor progress are (i) the efficient capturing of biorecognition signals and the transformation of these signals into electrochemical, electrical, optical, gravimetric, or acoustic signals (transduction process), (ii) enhancing transducer performance i.e., increasing sensitivity, shorter response time, reproducibility, and low detection limits even to detect individual molecules, and (iii) miniaturization of the biosensing devices using micro-and nano-fabrication technologies. Those challenges can be met through the integration of sensing technology with nanomaterials, which range from zero- to three-dimensional, possessing a high surface-to-volume ratio, good conductivities, shock-bearing abilities, and color tunability. Nanomaterials (NMs) employed in the fabrication and nanobiosensors include nanoparticles (NPs) (high stability and high carrier capacity), nanowires (NWs) and nanorods (NRs) (capable of high detection sensitivity), carbon nanotubes (CNTs) (large surface area, high electrical and thermal conductivity), and quantum dots (QDs) (color tunability). Furthermore, these nanomaterials can themselves act as transduction elements. This review summarizes the evolution of biosensors, the types of biosensors based on their receptors, transducers, and modern approaches employed in biosensors using nanomaterials such as NPs (e.g., noble metal NPs and metal oxide NPs), NWs, NRs, CNTs, QDs, and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology.

Abstract 14201: The Application of Hipsc-derived Cardiomyocytes Paced by Re-entrant Waves for Drug Assessment

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Junjun Li ◽  
Itsunari Minami ◽  
Shigeru Miyagawa ◽  
Xiang Qu ◽  
YING HUA ◽  
...  
Keyword(s):  
Cardiac Tissue ◽  
Troponin T ◽  
Field Potential ◽  
Electrical Signal ◽  
Assessment System ◽  
K Channel ◽  
Control Group ◽  
Culture Dish ◽  
Robust Response

Introduction: How to precisely evaluate response in newly developed medications in vitro may be a great concern in drug screening. We modified normal low-attachment culture dish and created closed-loop tissue ring from single hiPSC-CMs. We hypothesized that the re-entrant wave (ReW) could originate and pace the cardiac tissue ring, and the CMs under pacing could be matured and used for drug assessment. Methods: PDMS wells and pillars were mounted in low-attachment petri dishes (Figure 1A). 4 х 10 5 hiPSC-CMs were plated into the wells to form tissue ring where the ReW could spontaneously originate. After cultivation for 14 days, the hiPSC-CMs were evaluated by immunostaining and gene expression. Micro electrode array (MEA) were used to evaluating the CM response to different drugs. Results: The electrical signal recorded by MEA indicated that the ReWs could make the CMs beat at a much higher rate than the Control group (Figure 1B, 123.26 ± 10.36 bpm vs. 14.08 ± 4.53 bpm, p<0.0001). After 14 day culture, the ReW group demonstrated significantly higher expression of Troponin T (TnT2), myosin heavy chain 7 (β-MHC), and α-actinin. Interestingly, the α-actinin staining indicated alignment of CMs within the ReW group (Figure 1C). The CMs under ReW pacing showed robust response to several cardiac compounds including E4031, (hERG K+ channel blocker, Figure 1D and E), isoproterenol (β adrenoceptor agonist) and propranolol (beta-blocker). Both the field potential as well as the Ca 2+ transients showed correlated dose-dependent change and the recovering after washout of the drugs. Conclusions: The ReWs could spontaneously originate in the cultured cardiac tissue ring with enhancement of the maturation in the hiPSC-CMs and robust response to various drugs, indicating the system as a robust drug assessment system with multiple read-out methods.

scholarly journals Heterostructured silicon-germanium-silicon p-i-n avalanche photodetectors for chip-integrated optoelectronics -INVITED

2021 ◽  
Vol 255 ◽  
pp. 01002
Author(s):  
Daniel Benedikovic ◽  
Leopold Virot ◽  
Guy Aubin ◽  
Jean-Michel Hartmann ◽  
Farah Amar ◽  
...  
Keyword(s):  
Health Monitoring ◽  
Optical Communications ◽  
Silicon Germanium ◽  
High Speed ◽  
Near Infrared ◽  
Building Blocks ◽  
Electrical Signal ◽  
Avalanche Photodetectors ◽  
Infrared Wavelengths ◽  
Germanium Silicon

Optical photodetectors are at the forefront of photonic research since the rise of integrated optics. Photodetectors are fundamental building blocks for chip-scale optoelectronics, enabling conversion of light into an electrical signal. Such devices play a key role in many surging applications from communication and computation to sensing, biomedicine and health monitoring, to name a few. However, chip integration of optical photodetectors with improved performances is an on-going challenge for mainstream optical communications at near-infrared wavelengths. Here, we present recent advances in heterostructured silicon-germanium-silicon p-i-n photodetectors, enabling high-speed detection on a foundry-compatible monolithic platform.

scholarly journals Converting cellulose nanocrystals into photocatalysts by functionalisation with titanium dioxide nanorods and gold nanocrystals

RSC Advances ◽  
2020 ◽  
Vol 10 (61) ◽  
pp. 37374-37381
Author(s):  
Santhosh S. Nair ◽  
Jianhong Chen ◽  
Adam Slabon ◽  
Aji P. Mathew
Keyword(s):  
Titanium Dioxide ◽  
Surface Charge ◽  
Water Purification ◽  
Cellulose Nanocrystals ◽  
High Surface ◽  
High Surface Area ◽  
Building Blocks ◽  
Surface Groups ◽  
Gold Nanocrystals ◽  
Titanium Dioxide Nanorods

Cellulose nanocrystals (CNCs) are promising building blocks for water purification due to their high surface area, tuneability of surface charge and grafting of surface groups depending on the pollutants.

Improved Sensitivity of Dielectric Modulated Junctionless Transistor for Nanoscale Biosensor Design

2020 ◽  
Vol 18 (4) ◽  
pp. 328-333
Author(s):  
Shradhya Singh ◽  
Shashi Bala ◽  
Balwant Raj ◽  
Balwinder Raj
Keyword(s):  
Threshold Voltage ◽  
Drain Current ◽  
Label Free ◽  
Asymmetric Mode ◽  
Biomolecule Detection ◽  
Gate Operation ◽  
Voltage Change ◽  
Mode Of Operation ◽  
Junctionless Transistor ◽  
Detection Of Biomolecules

This work has proposed a device i.e., Dielectric Modulated (DM) Junctionless Transistor which is utilizes as Label-Free (LF) electrical characteristic detection of bio-molecules. The electrical characteristics used for the detection of biomolecules are electric field, surface potential, drain current and threshold voltage (Vth). Due to immobilization of biomolecules in the cavity region, the threshold voltage change in comparison to the absence of biomolecule, which is utilizes as the sensitivity metric. The sensitivity of biomolecule detection can be enhanced by using asymmetric gate operation of the device. In asymmetric mode the degree of sensitivity is almost five times higher than that of the symmetric mode of operation.

Charge Carrier Transport along Grain Boundaries in Silicon

2013 ◽  
Vol 205-206 ◽  
pp. 293-298 ◽  
Author(s):  
Martin Kittler ◽  
Manfred Reiche ◽  
Hans Michael Krause
Keyword(s):  
Charge Carrier ◽  
Grain Boundaries ◽  
Carrier Transport ◽  
Room Temperature ◽  
Drain Current ◽  
Charge Carriers ◽  
Strong Increase ◽  
Charge Carrier Transport ◽  
Mobility Of Charge Carriers

The influence of GBs contained in the channel of MOS-FETs - fabricated in thin SOI layers - is demonstrated. The drain current measured at room temperature increases about 50 times for nFETs and about 10 times for pFETs, respectively, as compared to reference devices. The observations might be interpreted as a strong increase of the mobility of charge carriers. Moreover, the observed stepwise changes of the drain current at 5 K may point to Coulomb blockades.

Influences of Carrier Transport on Drain-Current Variability of MOSFETs

2011 ◽  
Vol 470 ◽  
pp. 184-187 ◽  
Author(s):  
Kenji Ohmori ◽  
Kenji Shiraishi ◽  
Keisaku Yamada
Keyword(s):  
Carrier Transport ◽  
Drain Current ◽  
Short Channel ◽  
Short Channel Effect ◽  
Conduction Mechanisms ◽  
Channel Effect

We have investigated the static variability of p-MOSFETs by evaluating the drain current under various conditions of gate and drain voltages. The value of drain current variability (σId/Id) is proportional to (LW)-1/2 before the short channel effect appears, being similar to that of Vt variability. The magnitude of σId/Id decreases as the gate overdrive (Vg-Vt) decreases, and it is classified into two regimes that correspond to the carrier conduction mechanisms, namely diffusion and drift transports. This result strongly suggests that the dominant factors for determining σId/Id values are related to the carrier conduction mechanisms.

scholarly journals Scanning ion conductance microscopy reveals differences in the ionic environments of gram positive and negative bacteria

2020 ◽  
Author(s):  
Kelsey Cremin ◽  
Bryn Jones ◽  
James Teahan ◽  
Gabriel N. Meloni ◽  
David Perry ◽  
...  
Keyword(s):  
Cell Wall ◽  
Surface Charge ◽  
Wall Structure ◽  
Current Response ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Fem Model ◽  
Ion Conductance ◽  
E Coli ◽  
Scanning Ion Conductance Microscopy

AbstractThis paper reports on the use of scanning ion conductance microscopy (SICM) to locally map the ionic properties and charge environment of two live bacterial strains: the gramnegative Escherichia coli and the gram-positive Bacillus subtilis. SICM results find heterogeneities across the bacterial surface, and significant differences among the grampositive and -negative bacteria. The bioelectrical environment of the B. subtilis was found to be considerably more negatively charged compared to E. coli. SICM measurements, fitted to a simplified finite element method (FEM) model, revealed surface charge values of −80 to −140 mC m−2 for the gram-negative E. coli. The gram-positive B. subtilis show a much higher conductivity around the cell wall, and surface charge values between −350 and −450 mC m−2 were found using the same simplified model. SICM was also able to detect regions of high negative charge near B. subtilis, not detected in the topographical SICM response and attributed to extracellular polymeric substance. To further explore how the B. subtilis cell wall structure can influence the SICM current response, a more comprehensive FEM model, accounting for the physical properties of the gram-positive cell wall, was developed. The new model provides a more realistic description of the cell wall and allowed investigation of the relation between its key properties and SICM currents, building foundations to further investigate and improve understanding of the gram-positive cellular microenvironment.Abstract Figure

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