Self-powered sensor for trace Hg2+ detection

A self-powered electrochemical sensor has been facilely designed for sensitive detection of Hg(2+) based on the inhibition of biocatalysis process of enzymatic biofuel cell (BFC) for the first time. The as-prepared one-compartment BFC, which was consisted of alcohol dehydrogenase supported on single-walled carbon nanohorns-based mediator system as the anode and bilirubin oxidase as the cathodic biocatalyst, generated an open circuit potential (V(oc)) of 636 mV and a maximum power density of 137 μW cm(-2). It was interestingly found that the presence of Hg(2+) would affect the performance of the constructed BFC (e.g., V(oc)). Taking advantage of the inhibitive effect of Hg(2+), a novel self-powered Hg(2+) sensor has been developed, which showed a linear range of 1-500 nM (R(2) = 0.999) with a detection limit of 1 nM at room temperature. In addition, this BFC-type sensor exhibited good selectivity for Hg(2+) against other common environmental metal ions, and the feasibility of the method for Hg(2+) detection in actual water samples (i.e., tap, ground, and lake water) was demonstrated with satisfactory results.     

Mediatorless,Reversible Optical Nanosensor Enabled through Enzymatic Pocket Doping

Single‐walled carbon nanotubes (SWCNTs) exhibit intrinsic near‐infrared fluorescence that benefits from indefinite photostability and tissue transparency, offering a promising basis for in vivo biosensing. Existing SWCNT optical sensors that rely on charge transfer for signal transduction often require exogenous mediators that compromise the stability and biocompatibility of the sensors. This study presents a reversible, mediatorless, near‐infrared glucose sensor based on glucose oxidase‐wrapped SWCNTs (GOx‐SWCNTs). GOx‐SWCNTs undergo a selective fluorescence increase in the presence of aldohexoses, with the strongest response toward glucose. When incorporated into a custom‐built membrane device, the sensor demonstrates a monotonic increase in initial response rates with increasing glucose concentrations between 3 × 10^?3 and 30 × 10^?3m and an apparent Michaelis–Menten constant of K_M(app) ≈ 13.9 × 10^?3m . A combination of fluorescence, absorption, and Raman spectroscopy measurements suggests a fluorescence enhancement mechanism based on localized enzymatic doping of SWCNT defect sites that does not rely on added mediators. Removal of glucose reverses the doping effects, resulting in full recovery of the fluorescence intensity. The cyclic addition and removal of glucose is shown to successively enhance and recover fluorescence, demonstrating reversibility that serves as a prerequisite for continuous glucose monitoring.     

Direct detection of S-nitrosothiols using planar amperometric nitric oxide sensor modified with polymeric films containing catalytic copper species

The direct amperometric detection of S-nitrosothiol species (RSNOs) is realized by modifying a previously reported amperometric nitric oxide gas sensor with thin hydrophilic polyurethane films containing catalytic Cu(II)/(I) sites. Catalytic Cu(II)/(I)-mediated decomposition of S-nitrosothiols generates NO(g) in the thin polymeric film at the distal tip of the NO sensor. Three different species are examined to create the catalytic layer: (1) a lipophilic Cu(II)-ligand complex; (2) Cu(II)-phosphate salt; and (3) small (3-microm) metallic Cu(0) particles. All three catalytic layers yield reversible amperometric response in proportion to the concentration of S-nitrosothiols (e.g., nitrosocysteine, nitrosoglutathione, S-nitroso-N-acetylcysteine, S-nitrosoalbumin) present in the aqueous test solution. Sensitivity toward the different RSNO species is dependent on the respective catalytic rates of decomposition of the RSNO species by reactive Cu(I), accessibility of the species into the polyurethane layer containing the catalyst, the level of reducing agents (ascorbate) used in solution to help generate reactive Cu(I) species, and the concentration of metal ion complexing agents present in the test solution (e.g., EDTA). Under optimized conditions, all RSNO species can be detected at < or =1 microM levels, with sensor lifetimes of at least 10 days for the sensors based on Cu(II)-phosphate and Cu0 particles. It is further shown that the new RSNO sensors can be used to assess the "NO-generating" ability of fresh blood samples by effectively detecting the total level of reactive RSNO species present in such samples.     

Self-powered pressure sensor for ultra-wide range pressure detection

The next generation of sensors should be self-powered,maintenance-free,precise,and have wide-ranging sensing abilities.Despite extensive research and development in the field of pressure sensors,the sensitivity of most pressure sensors declines significantly at higher pressures,such that they are not able to detect a wide range of pressures with a uniformly high sensitivity.In this work,we demonstrate a single-electrode triboelectric pressure sensor,which can detect a wide range of pressures from 0.05 to 600 kPa with a high degree of sensitivity across the entire range by utilizing the synergistic effects of the piezoelectric polarization and triboelectric surface charges of self-polarized polyvinyldifluoride-trifluoroethylene (P(VDF-TrFE)) sponge.Taking into account both this wide pressure range and the sensitivity,this device exhibits the best performance relative to that of previously reported self-powered pressure sensors.This achievement facilitates wide-range pressure detection for a broad spectrum of applications,ranging from simple human touch,sensor networks,smart robotics,and sports applications,thus paving the way forward for the realization of next-generation sensing devices.Moreover,this work addresses the critical issue of saturation pressure in triboelectric nanogenerators and provides insights into the role of the surface charge on a piezoelectric polymer when used in a triboelectric nanogenerator.     

A High-Performance Hybrid Biofuel Cell with a Honeycomb-Like Ti3C2Tx/MWCNT/AuNP Bioanode and a ZnCo2@NCNT Cathode for Self-Powered Biosensing

This work focusses on developing a hybrid enzyme biofuel cell-based self-powered biosensor with appreciable stability and durability using murine leukemia fusion gene fragments (tDNA) as a model analyte. The cell consists of a Ti₃C₂T_x/multiwalled carbon nanotube/gold nanoparticle/glucose oxidase bioanode and a Zn/Co-modified carbon nanotube cathode. The bioanode uniquely exhibits strong electron transfer ability and a high surface area for the loading of 1.14 × 10⁻⁹ mol cm⁻² glucose oxidase to catalyze glucose oxidation. Meanwhile, the abiotic cathode with a high oxygen reduction reaction activity negates the use of conventional bioenzymes as catalysts, which aids in extending the stability and durability of the sensing system. The biosensor offers a 0.1 fm –1 nm linear range and a detection limit of 0.022 fm tDNA. Additionally, the biosensor demonstrates a reproducibility of ≈4.85% and retains ≈87.42% of the initial maximal power density after a 4-week storage at 4 °C, verifying a significantly improved long-term stability.     

Experimental platform to study heavy metal ion-enzyme interactions and amperometric inhibitive assay of Ag+ based on solution state and immobilized glucose oxidase

The heavy metal (HM) ion-enzyme interaction is an important research topic in many areas. Using glucose oxidase (GOx) as an example, a comprehensive experimental platform based on quartz crystal microbalance and electroanalysis techniques is developed here to quantitatively study the HM ion-enzyme interactions and amperometric inhibitive assays of HM ions. The effects of some common HM ions on the bioactivities of solution-state GOx (GOx(s)), electrode surface-adsorbed GOx (GOx(ads)), and polymer-entrapped GOx (GOx(e)) are comparatively examined on the basis of anodic amperometric detection of enzymatically generated H(2)O(2). Ag(+) shows the strongest inhibition effect among the HM ions examined, and the inhibitive assays of Ag(+) based on GOx(s), GOx(ads), and GOx(e) entrapped in poly(l-noradrenalin) (PNA) give limits of detection (LOD) of 2.0, 8.0, and 5.0 nM (S/N = 3), respectively. Inhibition effects of Hg(2+), Cu(2+), and Co(2+) are detectable only at 15 μM or higher concentrations, and the other HM ions show undetectable inhibition even at 1.0 mM. The developed experimental platform allows one to quantify the number of the bound HM ions per GOx(ads) molecule at various inhibition percentages. In addition, the electrosynthesized PNA matrix to entrap GOx for an inhibitive assay of Ag(+) shows the lowest competitive affinity to HM ions and gives the highest sensitivity, as compared with several other polymer matrixes commonly used for the inhibitive assay. The suggested experimental platform is recommended for wide applications in enzymatic inhibitive assays and quantitative studies of the inhibition effects of HM ions on many other redox-event-relevant enzymes.     

3D double-faced interlock fabric triboelectric nanogenerator for bio-motion energy harvesting and as self-powered stretching and 3D tactile sensors

Combining triboelectric nanogenerator (TENG) and textile materials, wearable electronic devices show great application prospects in biomotion energy harvesting and multifunctional self-power sensors in this coming intelligent era. However, fabrication method by rigidly stitching two or more individual fabrics together and working mode that must cooperate with external materials, make textile-based TENG bulky, stiff, uncomfortable and hinder their range of application. Here, by using a double needle bed flat knitting machine technology, a 3D double faced interlock fabric TENG (3DFIF-TENG) is designed as self-powered, stretchable and substrate-free wearable TENG sensors (such as a bending sensor to detect arm bending degree, pressure sensors) and energy harvesting devices. Besides, due to the unique 3D structure and after improving the structure by knitting a woven fabric-TENG in the middle layer, the 3DFIF-TENG can be further used as a multifunctional sensors, such as a 3D tactile sensor. Besides, by knitting a woven fabric-TENG in the middle layer of the 3DFIF-TENG, it can be further used as a multifunctional sensor, such as a 3D tactile sensor. The substrate-free and 3D structure design in this paper may provide a promising direction for self-powered, stretchable wearable devices in energy harvesting, human motion or robot movement detection, and smart prosthetics.     

A nanoparticle autocatalytic sensor for Ag+ and Cu2+ ions in aqueous solution with high sensitivity and selectivity and its application in test paper

A novel nanoparticle autocatalytic sensor for the detection of Ag(+) and Cu(2+) has been constructed based on the oxidative ability of Ag(+) and Cu(2+) toward o-phenylenediamine (OPDA). Ag(+) and Cu(2+) can be reduced to zerovalent silver and copper, respectively, and then such zerovalent Ag and Cu species form silver and copper nanoparticles that can catalyze the reaction between OPDA and Ag(+) and Cu(2+). In the reaction, OPDA is oxidized to 2,3-diaminophenazine (OPDAox), which has a fluorescence emission at 568 nm. Under the optimal conditions, Ag(+) and Cu(2+) can be detected in the concentration ranges from 60 nM to 60 μM and from 2.5 nM to 25 μM, respectively. Through this facile approach, Ag(+) and Cu(2+) can be detected down to 60 nM and 2.5 nM, respectively. In addition, the sensor is utilized for the detection of Ag(+) and Cu(2+) in sewage, and we have obtained very good results that are consistent with those of inductively coupled plasma-mass spectroscopy (ICP-MS). Moreover, such a nanoparticle autocatalytic sensor is applied to test paper for the detection of Ag(+) and Cu(2+) with the naked eye. With such test paper, Ag(+) and Cu(2+) could be detected at levels as low as 0.06 nmol and 0.3 nmol, respectively, with detection ranges of 0.06-60 nmol for Ag(+) and 0.3-60 nmol for Cu(2+), under the irradiation of UV light (365 nm). The test paper could be potentially used in the rapid detection of Ag(+) and Cu(2+) in real samples.     

Multilayer membranes via layer-by-layer deposition of glucose oxidase and Au nanoparticles on a Pt electrode for glucose sensing

We prepared multilayer membranes by the layer-by-layer deposition of glucose oxidase (GOx) and Au nanoparticles (5, 10, or 50 nm φ) on sensor substrates, such as a Pt electrode and a quartz glass plate, to prepare glucose sensors. The enzyme activity of GOx remained even in alternate assemblies, and the activity increased with the increasing number of depositions. The apparent K_m values of the deposited GOx were 28–32 mM, while a reported value in a solution is 33 mM. These results suggest that Au nanoparticles can be used as binders for the deposition of GOx without significant change in the affinity between GOx and glucose.     

Kinetic behavior of polymer-coated long-period-grating fiber-optic sensors

A new method of analysis employing the time-dependent response of long-period-grating (LPG) fiber-optic sensors is introduced. The current kinetic approach allows analysis of the time-dependent wavelength shift of the sensor, in contrast to previous studies, in which the LPG sensing element has been operated in an equilibrium mode and modeled with Langmuir adsorption behavior. A detailed kinetic model presented is based on diffusion of the analyte through the outer protective membrane coating into the affinity coating, which is bound to the fiber cladding. A simpler phenomenological approach presented is based on measurement of the slope of the time-dependent response of the LPG sensor. We demonstrate the principles of the kinetic methods by employing a commercial Cu+2 sensor with a carboxymethylcellulose sensing element. The detailed mathematical model fits the time-dependent behavior well and provides a means of calibrating the concentration-dependent time response. In the current approach, copper concentrations below parts per 10(6) are reliably analyzed. The kinetic model allows early-time measurement for low concentrations of the analyte, where equilibration times are long. This kinetic model should be generally applicable to other affinity-coated LPG fiber-optic sensors.     

Optical metal ion sensor based on diffusion followed by an immobilizing reaction. Quantitative analysis by a mesoporous monolith containing functional groups

A new optical metal ion sensor based on diffusion followed by an immobilizing reaction has been developed. The current sensor is based on a model that unifies two fundamental processes which a metal analyte undergoes when it is exposed to a porous, ligand-grafted monolith: (a) diffusion of metal ions to the binding sites and (b) metal-ligand (ML(n)) complexation. A slow diffusion of the metal ions is followed by their fast immobilizing reaction with the ligands in the monolith to give a complex. Inside the region where the ligands have been saturated, the diffusion of the metal ions reaches a steady state with a constant external metal ion concentration (C(0)). If the complex ML(n) could be observed spectroscopically, the absorbance of the product A(p) follows: A(p) = Kt(1/2), K = 2epsilon(p)(L(0)C(0)D)(1/2). D = diffusion constant of the metal ions inside the porous solid; L(0) = concentration of the ligands grafted in the monolith; and t = time. This equation is straightforward to use, and the K vs C(0)(1/2) plot provides the correlations with the concentrations (C(0)) of the metal ions. This is a rare optical sensor for quantitative metal ion analysis. The use of the model in a mesoporous sol-gel monolith containing grafted amine ligands for quantitative Cu(2+) sensing is demonstrated. This model may also be used in other chemical sensors that depend on diffusion of analytes followed by immobilizing reactions in porous sensors containing grafted/encapsulated functional groups/molecules.     

Employing the metabolic "branch point effect" to generate an all-or-none, digital-like response in enzymatic outputs and enzyme-based sensors

Here, we demonstrate a strategy to convert the graded Michaelis-Menten response typical of unregulated enzymes into a sharp, effectively all-or-none response. We do so using an approach analogous to the "branch point effect", a mechanism observed in naturally occurring metabolic networks in which two or more enzymes compete for the same substrate. As a model system, we used the enzymatic reaction of glucose oxidase (GOx) and coupled it to a second, nonsignaling reaction catalyzed by the higher affinity enzyme hexokinase (HK) such that, at low substrate concentrations, the second enzyme outcompetes the first, turning off the latter's response. Above an arbitrarily selected "threshold" substrate concentration, the nonsignaling HK enzyme saturates leading to a "sudden" activation of the first signaling GOx enzyme and a far steeper dose-response curve than that observed for simple Michaelis-Menten kinetics. Using the well-known GOx-based amperometric glucose sensor to validate our strategy, we have steepen the normally graded response of this enzymatic sensor into a discrete yes/no output similar to that of a multimeric cooperative enzyme with a Hill coefficient above 13. We have also shown that, by controlling the HK reaction we can precisely tune the threshold target concentration at which we observe the enzyme output. Finally, we demonstrate the utility of this strategy for achieving effective noise attenuation in enzyme logic gates. In addition to supporting the development of biosensors with digital-like output, we envisage that the use of all-or-none enzymatic responses will also improve our ability to engineer efficient enzyme-based catalysis reactions in synthetic biology applications.     

Microfabricated electrophoresis chips for simultaneous bioassays of glucose, uric acid, ascorbic acid, and acetaminophen

A micromachined capillary electrophoresis chip is described for simultaneous measurements of glucose, ascorbic acid, acetaminophen, and uric acid. Fluid control is used to mix the sample and enzyme glucose oxidase (GOx). The enzymatic reaction, a catalyzed aerobic oxidation of glucose to gluconic acid and hydrogen peroxide, occurs along the separation channel. The enzymatically liberated neutral peroxide species is separated electrophoretically from the anionic uric and ascorbic acids in the separation/reaction channel. The three oxidizable species are detected at the downstream gold-coated thick-film amperometric detector at different migration times. Glucose can be detected within less than 100 s, and detection of all electroactive constituents is carried out within 4 min. Measurements of glucose in the presence of acetaminophen, a neutral compound, are accomplished by comparing the responses in the presence and absence of GOx in the running buffer. The reproducibility of the on-chip glucose measurements is improved greatly by using uric acid as an internal standard. Factors influencing the performance, including the GOx concentration, field strength, and detection potential, are optimized. Such coupling of enzymatic assays with electrophoretic separations on a microchip platform holds great promise for rapid testing of metabolites (such as glucose or lactate), as well as for the introduction of high-speed clinical microanalyzers based on multichannel chips.     

Gas-liquid hybrid discharge-induced degradation of diuron in aqueous solution

Degradation of diuron in aqueous solution by gas-liquid hybrid discharge was investigated for the first time. The effect of output power intensity, pH value, Fe(2+) concentration, Cu(2+) concentration, initial conductivity and air flow rate on the degradation efficiency of diuron was examined. The results showed that the degradation efficiency of diuron increased with increasing output power intensity and increased with decreasing pH values. In the presence of Fe(2+), the degradation efficiency of diuron increased with increasing Fe(2+) concentration. The degradation efficiency of diuron was decreased during the first 4 min and increased during the last 10 min with adding of Cu(2+). Decreasing the initial conductivity and increasing the air flow rate were favorable for the degradation of diuron. Degradation of diuron by gas-liquid hybrid discharge fitted first-order kinetics. The pH value of the solution decreased during the reaction process. Total organic carbon removal rate increased in the presence of Fe(2+) or Cu(2+). The generated Cl(-1), NH(4)(+), NO(3)(-), oxalic acid, acetic acid and formic acid during the degradation process were also detected. Based on the detected Cl(-1) and other intermediates, a possible degradation pathway of diuron was proposed.     

Unusual response in mediated biosensors with an oxidase/peroxidase bienzyme system

Mediated biosensors consisting of an oxidase and peroxidase (POx) have attracted increasing attention because of their wide applicability. However, since most of oxidases utilize artificial electron acceptors in place of dioxygen, the competition between O2 and the electron acceptor in the mediated sensors is anticipated. This has been evidenced with a glucose oxidase (GOx)- and POx-coentrapped and ferrocene-embedded carbon paste electrode, which exhibits peak-shaped current-time curves at increased concentrations of glucose and also gives a peak-shaped calibration curve. Digital simulation has been applied to clarify the cause of such unusual responses, by taking into account the ping-pong enzyme kinetics on two- and three-substrate models for POx and GOx, respectively. The simulation has well reproduced such unusual responses and has clearly revealed that the depletion of O2 in the enzyme layer is the most important factor responsible for such unusual responses. To overcome such a drawback of oxidase/POx bienzyme sensors, it is expected to be essential to decrease the rate of the oxidase reaction. In contrast, increase in the POx activity is useful to improve the sensitivity. According to the simulation-based expectation, the GOx and POx concentrations in the bienzyme sensor are adjusted to exhibit normal behavior with high sensitivity.     

Flexible single walled nanotube based chemical sensor for 2,4-dinitrotoluene sensing

In this work, we have attempted to fabricate flexible single walled carbon nanotube based sensor for detection of 2,4-dinitrotoluene (DNT) an explosive chemical. For analyte sensing study, the flexible sensor is fabricated by vacuum filtration method. These fabricated gas sensors are characterised by SEM and Raman spectroscopy. The sensor response is investigated toward the explosive chemicals which have NO₂ group in their molecular structure. The fabricated sensor is able to detect the traces of DNT at room temperature. The sensor gives 0.28–0.32% repeatable response to 0.22 ppm of DNT. The response of sensor increases with increase in the vapour concentration of the DNT vapours.     

DNAzyme-based colorimetric sensing of lead (Pb(2+)) using unmodified gold nanoparticle probes

Novel functional oligonucleotides, especially DNAzymes with RNA-cleavage activity, have been intensively studied due to their potential applications in therapeutics and sensors. Taking advantage of the high specificity of 17E DNAzyme for Pb(2+), highly sensitive and selective fluorescent, electrochemical and colorimetric sensors have been developed for Pb(2+). In this work, we report a simple, sensitive and label-free 17E DNAzyme-based sensor for Pb(2+) detection using unmodified gold nanoparticles (GNPs) based on the fact that unfolded single-stranded DNA could be adsorbed on the citrate protected GNPs while double-stranded DNA could not. By our method the substrate cleavage by the 17E DNAzyme in the presence of Pb(2+) could be monitored by color change of GNPs, thereby Pb(2+) detection was realized. The detection of Pb(2+) could be realized within 20?min, with a detection limit of 500?nM. The selectivity of our sensor has been investigated by challenging the sensing system with other divalent metal ions. Since common steps such as modification and separation could be successfully avoided, the sensor developed here could provide a simple, cost-effective yet rapid and sensitive measurement tool for Pb(2+) detection and may prove useful in the development of sensors for clinical toxicology and environmental monitoring in the future.     

High-basicity determination in mixed water-alcohol solutions by a dual optical sensor approach

The activity of NaOH is known to be significantly affected by the presence of an alcohol in aqueous solutions. A novel linear relationship between (deltaA/deltaC(alcohol)) and C(base) was found in the highly alkaline, mixed H2O-ROH solutions (R = Me, Et, i-Pr). The use of this linear relationship led to a dual-transducer approach to decompose the optical signals of optical base sensors and to give base and alcohol concentrations in concentrated NaOH-H2O-ROH solutions ([OH-] = 0.05-3.6 M). The scope of the new dual-sensor approach was evaluated, and errors in C(base) and C(alcohol) were analyzed. The optical base sensors consist of sol-gel SiO2-ZrO2-organic polymer composites doped with high-pKa indicators. The pKa(s) of the indicators encapsulated in the composite films were determined and found to be affected by the composition of the sol-gel composites. Optical sensors and their uses in multicomponent systems are of intense current interest.( 1-7) In the multicomponent systems, the activity of the analyte and sensor response are often affected by change in ionic strength. For optical sensors that are based on indicator equilibria involving the analyte as their transducing mechanism, such effect is particularly significant. The concentrations of both the analyte and other chemicals affect ionic strength, and the sensor response to concentration of the analyte is thus often indistinguishable from those of other chemicals. An accurate measurement of each component in these multicomponent systems is actively studied. Several approaches have been developed to correct ionic strength in optical sensing for the pH region and solutions of low-to-medium ionic strength. (1-9) We recently reported a dual-transducer approach to measure acid concentrations (2-9 M HCl) in salt-containing, concentrated strong acids such as MClx-HCl (M = Li, Ca, Al) solutions. (10) This approach was shown to reduce the error in C(acid) from, for example,     

Self-powered system with wireless data transmission

We demonstrate the first self-powered system driven by a nanogenerator (NG) that works wirelessly and independently for long-distance data transmission. The NG was made of a free cantilever beam that consisted of a five-layer structure: a flexible polymer substrate, ZnO nanowire textured films on its top and bottom surfaces, and electrodes on the surfaces. When it was strained to 0.12% at a strain rate of 3.56% S(-1), the measured output voltage reached 10 V, and the output current exceeded 0.6 μA (corresponding power density 10 mW/cm(3)). A system was built up by integrating a NG, rectification circuit, capacitor for energy storage, sensor, and RF data transmitter. Wireless signals sent out by the system were detected by a commercial radio at a distance of 5-10 m. This study proves the feasibility of using ZnO nanowire NGs for building self-powered systems, and its potential application in wireless biosensing, environmental/infrastructure monitoring, sensor networks, personal electronics, and even national security.     

A Self-Powered Angle Sensor at Nanoradian-Resolution for Robotic Arms and Personalized Medicare

As the dominant component for precise motion measurement, angle sensors play a vital role in robotics, machine control, and personalized rehabilitation. Various forms of angle sensors have been developed and optimized over the past decades, but none of them would function without an electric power. Here, a highly sensitive triboelectric self-powered angle sensor (SPAS) exhibiting the highest resolution (2.03 nano-radian) after a comprehensive optimization is reported. In addition, the SPAS holds merits of light weight and thin thickness, which enables its extensive integrated applications with minimized energy consumption: a palletizing robotic arm equipped with the SPAS can precisely reproduce traditional Chinese calligraphy via angular data it collects. In addition, the SPAS can be assembled in a medicare brace to record the flexion/extension of joints, which may benefit personalized orthopedic recuperation. The SPAS paves a new approach for applications in the emerging fields of robotics, sensing, personalized medicare, and artificial intelligence.