Nanosensor Research Articles

A nano sensor for sensitive and selective detection of Cu2+ based on fluorescein: Cell imaging and drinking water analysis.

A fluorescein-based nano probe was designed and synthesized for ultra-sensitive detection of Cu2+ in aqueous solution. The formation of fluorescent organic nanoparticles confirmed by using particle size analysis and scanning electron microscopy. UV-Vis. absorption and fluorescence spectroscopy displays excellent photophysical properties of prepared nanoparticles as compared to parent molecule i.e. N-(3',6'-dihydroxy-3-oxo-3,3a-dihydrospiro[isoindole-1,9'-xanthene]-2(7aH)-yl)-1-naphthamide (FNH) in acetone. A series of 18 metal ion was examined with FNH nanoparticles (FNHNPs) to examine the change in fluorescence response. Pleasingly, only copper ion (Cu2+) shows selective and sensitive fluorescence enhancement effect, which discussed on chelation-enhanced fluorescence phenomenon. Other competing metal ions does not affect the FNHNPs fluorescence enhancement induced by Cu2+ ion. The excited state complexation through chelation-enhanced fluorescence of FNHNPs was further supported by UV-Vis. absorption and fluorescence decay titration of FNHNPs with and without the addition of Cu2+. The present investigation approach serves extremely low detection limit of 1.62 ng/mL (0.024 μM) for Cu2+ in aqueous solution. In addition, benefit of present study includes practical application for the quantitative estimation of Cu2+ in drinking water sample and intracellular cell imaging for Cu2+.

Adsorption of CO gas molecules on zigzag BN/AlN nanoribbons for nano sensor applications

First-principle calculations have been performed to study the sensing of CO gas in various considered configurations. The adsorption of CO on zigzag BN nanoribbon (ZBNNR) and zigzag AlN nanoribbon (ZAlNNR) was modelled in five different possibilities. The effect of CO adsorption is to reduce the band gap in both types (BN/AlN) of the nanoribbons. Interestingly, a finite magnetic moment (0.96 μB for ZBNNR and 0.69 μB for ZAlNNR) has been obtained which depends upon the adsorption configuration of CO. Half-metallicity was also observed upon selective CO adsorption on ZAlNNR irrespective of the ribbon width. Present findings suggest that CO gas molecules could be detected through adsorption on BN/AlN nanoribbons via changes in electronic and/or magnetic properties.

Efficient and selective sensing of nitrogen-containing gases by Si2BN nanosheets under pristine and pre-oxidized conditions

Motivated by the promise of two-dimensional nanostructures in the field of gas sensing, we have employed van der Waals corrected density functional theory calculations to study the structural, electronic and gas sensing propensities of the recently designed Si2BN monolayer. Our rigorous simulations reveal that the representative members of nitrogen-containing gases (NCGs) such as NO, NO2 and NH3 binds extremely strongly on pristine Si2BN monolayer. However, a strong dissociative adsorption in case of NO and NO2 would poison the Si2BN and ultimately reversibility of the monolayer would be compromised. Exploring the sensing mechanism in more realistic pre-oxidized conditions, the binding characteristics of O2@Si2BN changed dramatically, resulting into much lower adsorption in associative manner for all NO, NO2 and NH3. A visible change in work function indicates the variation in conductivity of O2@Si2BN upon the exposure of incident gases. Sustainable values of binding energies would also ensure a quick recovery time that makes O2@Si2BN an efficient nano sensor for pollutants like NCGs.

Silicon dioxide based Nano sensor to measure glucose level in blood

Diabetes is a growing problem affecting many people in the world. Diabetes leads to various complications like lower limb amputations, blindness, cardiovascular disease etc. Diabetes has many complexity that is reduced by individual monitoring and control of glucose level. Glucose level monitoring occur with recent development in Nanotechnology. Nanotechnology develops nanosensors which measure glucose level. Nanosensors fabricated by silicon dioxide in mass production reduces the cost of the nanosensors. Nanosensors made of silicon dioxide read the blood samples of a person without diabetes and a diabetic person with the help of SIGVIEW and analyzed using MATLAB. Statistical analysis is made with comparison of spectrogram, magnitude response, probability distribution, time domain and the autocorrelation of normal blood signals and diabetic signals. Comparison results in separation of a normal and diabetic person with an excellent performance of nanosensors in mass production.

The Sensing Applications in U-Shape Structure Based on Dual Transparency Windows

We have researched a U-shape structure that consists of three vertical cavities coupled with bus wave-guide. The theoretical results based on the coupled mode theory are consistent with simulation results. We demonstrate that the interaction among two bright and one dark modes lead to dual plasmon induced transparency. Meanwhile, it is found that the lateral displacement S plays an important role in the transmission property, and the transmission dip with different transmittance in various lateral displacement S has been explained theoretically. Moreover, the nano sensor has a sensitivity of 1225 nm shift per refractive index unit, and the figure of merit is up to 62.5. The proposed structure has the advantages of simple and compact structure, easy fabrication, and the ultra-compact structure holds great potential to the control of light in highly integrated optical circuits and nano sensor.

Superior sensing affinities of acetone towards vacancy induced and metallized ZnO monolayers

The sensing propensities of acetone molecule towards zinc oxide monolayers (ZnO-ML) have been studied by means of density functional theory (DFT) calculations. Our van der Waals induced first principles calculations revealed that pristine ZnO-ML barely binds acetone, which limits its application as acetone sensing materials. However the formation of vacancies and foreign element doping improves acetone binding drastically. Among several defects, divacancy, and metal doping Li, Sc and Ti functionalization on ZnO-ML has been found the most promising ones. Presence of dangling electrons and partial positive charges in case of vacancy-induced and metallized ZnO-ML respectively, is believed to enhance the binding of acetone on the monolayers. The acetone-ZnO binding behavior has been further explained through studying the electronic properties by density of states and charge transfer mechanism though Bader analysis. Thus defected and metallized ZnO-ML could be a promising nano sensor for efficient sensing/capture of acetone.

Adaptive mobility-based intelligent decision-making system for driver behaviour prediction with motion nano sensor in VANET

Vehicular ad-hoc network (VANET) offers a dedicated short-range wireless communication among vehicles on the road and to the road side unit. This paper contributes towards an intelligent decision-making system based on the driver behaviour under normal, reckless, fatigue and drunken conditions, and in developing a mobility model to adapt these support vector machine (SVM) classifier behaviours. Attributes such as speed, accelerometer, alcohol and eye blink values are fed to the mega trend diffusion (MTD) function and the attributes are merged and they are classified using SVM. The basic decisions are made by fuzzy interference system (FIS) which is used to find the driver behaviour and is predicted and appropriate decision will be taken for SVM classification. According to the behaviour of the driver, the speed and direction of the vehicle will be affected and it will be reflected in the mobility pattern of other vehicles. In this work, motion nano sensor was used to sense the values to control the driver behaviour.

Plasmon induced transparency and refractive index sensing in a new type of graphene-based plasmonic waveguide

The plasmon induced transparency (PIT) effect is investigated in a graphene-based waveguide, which is composed of a graphene bus waveguide side-coupled with a graphene strip directly and a graphene ring indirectly. Conventional numerical simulations based on finite element method (FEM) are used to study the transmission properties through optimizing the relevant parameters, and it is proved that the simulation results agree well with the analytical results. Then as one of the potential application branches of the PIT-like effect, the property of refractive index sensing with a higher sensitivity of 4160 nm/RIU is further studied. The result can help to deepen the understanding of PIT-like effect and nano sensor, and it would be also beneficial for the studies and applications of nanoscale graphene-based optical devices.

On-Demand Probabilistic Polling for Nanonetworks Under Dynamic IoT Backhaul Network Conditions

Driven by the high sensing resolution provided by advanced nano technologies, electromagnetic-based wireless nano sensor networks (EM-WNSNs) operating in the terahertz (THz) band is becoming an integral part of the Internet of Things (IoT). Data acquisition for EM-WNSNs faces two challenges: 1) the dynamic IoT backhaul bandwidth and 2) THz channel conditions that jointly impact resource utilization efficiency. Specifically, the mismatch between the demands of the EM-WNSNs and the available bandwidth of the backhaul link reduces the bandwidth efficiency of IoT backhaul or the energy efficiency of EM-WNSNs. To address the new constraints that emerge from the EM-WNSN, an on-demand probabilistic (OP) polling scheme is proposed for the backhaul tier of EM-WNSNs which is composed of nano sinks that aggregate and transport data from nano sensors to the IoT gateway. OP polling adjusts the packet aggregation process of nano sinks according to the up-to-date network conditions. From performance evaluation, OP polling achieves an 18% higher bandwidth efficiency compared to the previously proposed on-demand efficient polling and 69% less energy consumption compared to the greedy polling.

Improved sensing characteristics of methane over ZnO nano sheets upon implanting defects and foreign atoms substitution

Thanks to the growing interests of metal oxide sensors in environmental and industrial uses, this study presents the sensing mechanism of methane gas (CH4) on recently synthesized two-dimensional form of ZnO, ZnO nano sheets (ZnO-NS). The adsorption energy of CH4 on pristine ZnO-NS, calculated by means of van der Waals corrected first-principles calculations, is found to be insufficient restricting its application as an efficient nano sensor. However, the creation of (O/Zn) vacancies and the substitution of foreign dopants into ZnO-NS considerably intensify the binding energy of CH4. Through a comprehensive energetic analysis, it is observed that among all the substituents, boron (B), sulphur (S) and gallium (Ga) improves the binding of CH4 to 2.75, 6.1 and 7.5 times respectively than its values on pristine ZnO-NS. In addition to the CH4 binding energies falling ideally between physisorption and chemisorption range, a prominent variation in the electronic properties before and after CH4 exposure indicates the promise of substituted Zn-NS as a useful nano sensors.

Ion-Selective Nanosensor for Photoacoustic and Fluorescence Imaging of Potassium.

Ion-selective optodes (ISOs), the optical analog of ion-selective electrodes, have played an increasingly important role in chemical and biochemical analysis. Here we extend this technique to ion-selective photoacoustic optodes (ISPAOs) that serve at the same time as fluorescence-based ISOs, and apply it specifically to potassium (K+). Notably, the potassium ion is one of the most abundant cations in biological systems, involved in numerous physiological and pathological processes. Furthermore, it has been recently reported that the presence of abnormal extracellular potassium concentrations in tumors suppresses the immune responses and thus suppresses immunotherapy. However, unfortunately, sensors capable of providing potassium images in vivo are still a future proposition. Here, we prepared an ion-selective potassium nanosensor (NS) aimed at in vivo photoacoustic (PA) chemical imaging of the extracellular environment, while being also capable of fluorescence based intracellular ion-selective imaging. This potassium nanosensor (K+ NS) modulates its optical properties (absorbance and fluorescence) according to the potassium concentration. The K+ NS is capable of measuring potassium, in the range of 1 mM to 100 mM, with high sensitivity and selectivity, by ISPAO based measurements. Also, a near infrared dye surface modified K+ NS allows fluorescence-based potassium sensing in the range of 20 mM to 1 M. The K+ NS serves thus as both PA and fluorescence based nanosensor, with response across the biologically relevant K+ concentrations, from the extracellular 5 mM typical values (through PA imaging) to the intracellular 150 mM typical values (through fluorescence imaging).

Adsorption of NO2 molecules on armchair phosphorene nanosheet for nano sensor applications – A first-principles study

The electronic and NO2 adsorption properties of hydrogenated armchair phosphorene nanosheet device is investigated through density functional theory (DFT) and non-equilibrium Green’s function method (NEGF). The armchair phosphorene nanosheet is used for the detection of NO2 gas in phosphorene molecular device. The DOS spectrum demonstrates the change in peak maxima due to transfer of electrons between NO2 gas and phosphorene base material. The change in the peak amplitude is observed along the valance band as well as in the conduction band in the transmission spectrum of phosphorene device. I–V characteristics support the change in the current upon adsorption of NO2 gas molecule on phosphorene molecular device. Using formation energy, structural stability of phosphorene nanosheet has been studied. The adsorption properties of NO2 on phosphorene nanosheet have also been investigated with the help of adsorption energy, Mulliken charge and Bader charge analysis. In order to ascertain the selectivity of NO2 gas along phosphorene molecular device in the ambient condition, the adsorption behavior of O2 and CO2 is also studied. The findings of the present work confirm that phosphorene molecular device can be used as a NO2 gas sensor and also the influence of Al substitution in phosphorene nanosheet device is explored and reported.

EEWNSN: Energy Efficient Wireless Nano Sensor Network MAC Protocol for Communications in the Terahertz Band

Wireless Nano Sensor Networks (WNSNs) are a dense deployment of nano sensors that communicate through electromagnetic waves over the Terahertz band (0.1–10 THz). The extreme energy, processing power and memory capacity limitation of nano-scale devices and the peculiarities of high operating frequency introduce the requirement to design novel communication paradigm and light MAC protocols for WNSNs. In this paper, we present a new Energy Efficient Wireless Nano Sensor Network MAC protocol (EEWNSN-MAC) for mobile multi-hop wireless nanonetworks. The proposed protocol takes advantage of the clustering mechanism and TDMA scheduling scheme to alleviate the mobility effects and transmission collisions. We evaluate performance of the EEWNSN-MAC protocol compared with a similar previously proposed nano-MAC protocol called “Smart-MAC”. For this purpose, we utilize a new NS-3 simulator module named nano-sim. This evaluation is done for three critical metrics in WNSN, namely, the total energy that is consumed per sent/received packet on the network, the packet loss ratio (PLR) and scalability. Finally, the simulation results demonstrate that the EEWNSN-MAC protocol improves the network performance in terms of energy consumption and PLR and it is more scalable compared to the “Smart-MAC” algorithm.

New nanosensor for mapping the brain

New nanosensor for mapping the brain

Heterogeneous time-resolved electrochemiluminoimmunoassay of thyroid stimulating hormone with magnetic beads at oxide-covered aluminum electrode

The heterogeneous immunoassay of thyroid stimulating hormone (TSH) was detected by the time-resolved cathodic electrochemiluminescence immunoassay (tr-CECLIA) method using magnetic beads as a mobile support. The magnetic beads coated with sandwich type TSH immunoassay were captured with a magnet for washing and detection processes. The time-resolved cathodic electrochemiluminescence (tr-CECL) signal of Tb(III) chelate label was generated by cathodic pulse polarization in the aluminum working electrode and platinum counter electrode system. The detection method causes injection of high energy electrons into the aqueous solution near the aluminum electrode and creates rigid simultaneous oxidative and reductive conditions that excitate the Tb(III) chelate used as a label luminophore in the heterogeneous sandwich type immunoassay of TSH in the surface of the magnetic beads. The limit of detection of the method was about 50mIUL−1. The precision of it was noticed to be good; the coefficient variation percentage was realized to be lower than 10 %. Unfortunately the limit of detection is not good enough for determination of analyte levels of very low concentrations for instance TSH in body fluids. The possible application areas of the method are in highly sophisticated micro or nano fluidic detection and sensor systems where the aspiration level of the analyte detection limit is not very high and the mobility and manageability and the large surface area of the magnetic beads can be utilized efficiently in separating, washing, moving, coating and detecting processes. In the case of tr-CECLIA the presented method makes possible to use multipurpose working electrodes instead of disposable ones.

Adaptive mobility-based intelligent decision-making system for driver behaviour prediction with motion nanosensor in VANET

Vehicular ad-hoc network (VANET) offers a dedicated short-range wireless communication among vehicles on the road and to the road side unit. This paper contributes towards an intelligent decision-making system based on the driver behaviour under normal, reckless, fatigue and drunken conditions, and in developing a mobility model to adapt these support vector machine (SVM) classifier behaviours. Attributes such as speed, accelerometer, alcohol and eye blink values are fed to the mega trend diffusion (MTD) function and the attributes are merged and they are classified using SVM. The basic decisions are made by fuzzy interference system (FIS) which is used to find the driver behaviour and is predicted and appropriate decision will be taken for SVM classification. According to the behaviour of the driver, the speed and direction of the vehicle will be affected and it will be reflected in the mobility pattern of other vehicles. In this work, motion nano sensor was used to sense the values to control the driver behaviour.

Application of Polyaniline Nanoparticles Modified Screen Printed Carbon Electrode as a Sensor for Determination of Hg(II) in Environmental Samples

We have described the development of electrochemical nano sensor for the detection of mercury ions from aqueous solutions based on the formation of polyaniline nanoparticle films. Screen printed carbon electrodes were modified with polyaniline nanoparticles. Electropolymerization of polyaniline nanoparticles was performed by the pulsed potentiostatic method. The sample of polyaniline nanoparticles was prepared by repeating the potential step process three times. Structural and morploigcal characterization of polyaniline nanoparticles modified screen printed carbon electrode was performed using Fourier Transmission infrared (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). PANI nanoparticles were spherical shaped having an apparent dimeter varying from 20 to 45 nm. Square wave anodic stripping voltammetry was used for the detection of Hg(II) on PANI NPs modified screen printed carbon electrode under optimized conditions. Hg(II) was deposited for 60 seconds by the reduction of Hg(II) in buffer solution:(citric acid and sodium chloride pH 2.30), followed by Hg stripping between 0.3 and 0.8 V at the following parameters: Scan rate: 100 mV s-1, frequency: 60 Hz, amplitude: 0.025 V and increment: 4.0 mV. it was found that the PANI NPs modified screen printed carbon electrode had a highest anodic stripping peak current in solution of pH 2.30. The limit of detection value for Hg(II) was found to be 2.50 ± 0.03 ppb. The limits of detections determined are below the corresponding guideline value from the World Health Organization (WHO). In addition, the modified nano electrode exhibited excellent reproducibility and high stability. The developed method was successfully applied to determine Hg(II) in real water samples with satisfactory results.

Application of nanotechnology in petroleum exploration and development

Combined with the actual demand of oil and gas exploration and development, this paper summarizes the research progress and application of nanotechnology in various fields of petroleum exploration and development, discusses and prospects the application and development of nanotechnology in the future. Nano characterization technology has played an important role in the analysis of the mineral composition, micro pore structure and rock physical properties of unconventional reservoirs; the reservoir nano sensor is still in the laboratory stage, and the reservoir nano robots still need a key technology breakthrough; numerical simulation technology of oil and gas migration in micro-nano porous media will become an important means of unconventional oil and gas migration mechanism, distribution pattern and resource evaluation; nano materials have size and surface effect, wetting characteristics, inhibition characteristics of particle migration, shear thickening behavior, nanometer photocatalytic properties, nano filtration and nano corrosion and wear resistance. Nano materials have broad application prospects in the fields of enhanced oil recovery, water treatment, engineering anti-corrosion. There are three aspects of future development of nanotechnology, i.e., nano characterization and numerical simulation, nano sensing and nano materials. In-situ modification of low grade oil and gas resources and synthesis of oil and gas by nano photosynthesis are the two potential development directions.

In-plane vibration of FG micro/nano-mass sensor based on nonlocal theory under various thermal loading via differential transformation method

In the present study, free vibration model of a cantilever functionally graded (FG) nanobeam with an attached mass at tip and under various thermal loading and two types of material distribution is introduced. The vibration performance is considered using nonlocal Euler-Bernoulli beam theory. Two types of thermal loading, namely, uniform and nonlinear temperature rises through the thickness direction are considered. Thermo-mechanical properties of FG nano mass sensor are supposed to vary smoothly and continuously throughout the thickness based on power-law and Mori Tanaka distributions of material properties. Eringen non-local elasticity theory is exploited to describe the size dependency of FG nanobeam. The governing equations of the system with both axial and transverse displacements are derived based on Hamilton's principle and solved utilizing the differential transformation method (DTM) to find the non-dimensional natural frequencies. The results have good agreements with those discussing in the literature. After validation of the present model, the effect of various parameters such as mass and position of the attached nano particle, FG power-law exponent, thermal load type, material distribution type and nonlocal parameter on the frequency of nano sensor are studied. It is shown that the present model produces results of high accuracy, and it can be used as a benchmark in future studies of the free vibration of FG Nano-Mass Sensors.

NO gas sensing kinetics at room temperature under UV light irradiation of In2O3 nanostructures.

In2O3 nanostructure sensors were fabricated by arc-discharging a source composed of a graphite tube containing indium. The NO gas sensing properties, as well as the morphology, structure, and electrical properties, were examined at room temperature under UV light illumination. In particular, the response and recovery kinetics of the sensor at room temperature under various UV light intensities were studied. The maximum response signal was observed at an intermediate UV light intensity, which could be corroborated by a nano-size effect based on the conduction model of a resistive chemical nano sensor. The mechanism for the enhanced adsorption/desorption kinetics for NO in an air environment under UV light irradiation is discussed in detail. Furthermore, the general requirements of the sensor, including the stability, repeatability, and selectivity, are discussed.