A5040515749- Electrochemical sensors and biosensors
- Advanced biosensing and bioanalysis techniques
- Electrochemical Analysis and Applications
- Neuroscience and Neural Engineering
- Conducting polymers and applications
- Carbon Nanotubes in Composites
- Analytical Chemistry and Sensors
- Graphene research and applications
- Advanced Chemical Sensor Technologies
- Neurological disorders and treatments
- Molecular Junctions and Nanostructures
- Supercapacitor Materials and Fabrication
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Spaceflight effects on biology
- Biosensors and Analytical Detection
- Force Microscopy Techniques and Applications
- Astro and Planetary Science
- Space Exploration and Technology
- Nanotechnology research and applications
- Advanced Sensor and Energy Harvesting Materials
- Gas Sensing Nanomaterials and Sensors
- Advanced Biosensing Techniques and Applications
- Planetary Science and Exploration
- Diamond and Carbon-based Materials Research
Ames Research Center
2015-2025
SLAC National Accelerator Laboratory
2019
The Open University
2019
NASA Research Park
2019
Sensors (United States)
2019
University of California, Davis
2008-2011
Santa Clara University
2000-2003
A nanoelectrode array based on vertically aligned multiwalled carbon nanotubes (MWNTs) embedded in SiO2 is used for ultrasensitive DNA detection. Characteristic electrochemical behaviors are observed measuring bulk and surface-immobilized redox species. Sensitivity dramatically improved by lowering the nanotube density. Oligonucleotide probes selectively functionalized to open ends of nanotubes. The hybridization subattomole targets can be detected combining such electrodes with Ru(bpy)32+...
We report a novel approach for the fabrication of nanoelectrode arrays using vertically aligned multi-walled carbon nanotubes (MWCNTs) embedded within SiO2 matrix. Cyclic voltammetry and pulse are employed to characterize electrochemical properties MWCNT array. The unique graphitic structure nanoelectrodes is compared with model systems such as highly oriented pyrolytic graphite glassy electrodes. Low-density display independent behavior showing diffusion-limited steady-state currents in...
A label-free biosensor is presented using carbon nanofiber (CNF) nanoelectrode arrays for the detection of cardiac troponin-I in early diagnosis myocardial infarction. Immobilization anti-cTnI Ab on CNFs and human-cTnI were examined electrochemical impedance spectroscopy cyclic voltammetry techniques. Each step modification process was monitored, results show changes electrical capacitance or resistance to charge transfer due specificity corresponding adsorption Ab-Ag interaction. The...
In this paper we describe a method for three-dimensional wax patterning of microfluidic paper-based analytical devices (μPADs). The is rooted in the fundamental details transport and provides simple way to fabricate complex channel architectures such as hemichannels fully enclosed channels. We show that μPADs can be fabricated with half much by using rather than ordinary open also provide evidence channels are efficiently isolated from exterior environment, decreasing contamination risks,...
We report the detection of DNA PCR amplicons using an ultrasensitive label-free electronic technique based on multiwalled carbon nanotube (MWNT) nanoelectrode arrays embedded in SiO2 matrix. Specific are reliably detected electrochemical (EC) methods through allele-specific oligonucleotide hybridization. The inherent guanine bases amplicon target serve as signal moieties with aid Ru(bpy)32+ mediators, providing amplified anodic current associated oxidation groups at surface. reduced size and...
Reducing cost and time is the major concern in clinical diagnostics, particularly molecular diagnostics. Miniaturization technologies have been recognized as promising solutions to provide low-cost microchips for With recent advancement nanotechnologies, it possible further improve detection sensitivity simplify sample preparation by incorporating nanoscale elements diagnostics devices. A fusion of micro- nanotechnologies with biology has great potential development disposable chips rapid...
Abstract The rapid development in nanomaterials and nanotechnologies has provided many new opportunities for electroanalysis. We review our recent results on the fabrication electroanalytical applications of nanoelectrode arrays based vertically aligned multi‐walled carbon nanotubes (MWCNTs). A bottom‐up approach is demonstrated, which compatible with Si microfabrication processes. MWCNTs are encapsulated SiO 2 matrix leaving only very end exposed to form inlaid arrays. electrical...
We present an approach to tackle long-standing problems in contacts, thermal damage, pinhole induced short circuits and interconnects molecular electronic device fabrication integration. Our uses metallic nanowires as top electrodes connect interconnect wires assembled on electrode arrays crossbar architectures. Using this simple reliable approach, we have revealed intriguing memory effects for several different wires, demonstrated their applications arrays. has great potential be used fast...
A carbon nanofiber (CNF) electrode array was integrated with the Wireless Instantaneous Neurotransmitter Concentration Sensor System (WINCS) for detection of dopamine using fast scan cyclic voltammetry (FSCV). Dopamine performance by CNF arrays comparable to that traditional fiber microelectrodes (CFMs), demonstrating can be utilized as an alternative neurochemical monitoring.
The surface properties of the electrode materials play a crucial role in determining performance and efficiency energy storage devices. Graphene oxide nanostructures 3d transition metal oxides were synthesized for construction electrodes supercapacitors, electronic structure oxidation states probed using near-edge X-ray absorption fine structure. Understanding chemistry graphene would provide valuable insight into its reactivity as transformation to reduced-graphene is key step synthesis...
Recent interest in flexible electronics and wearable devices has created a demand for fast highly repeatable printing processes suitable device manufacturing. Robust technology is critical the integration of sensors other on substrates such as paper textile. An atmospheric pressure plasma-based process been developed to deposit different types nanomaterials substrates. Multiwalled carbon nanotubes were deposited demonstrate site-selective deposition well direct without any type patterning....
Detailed information about the physicochemical properties of a given surface is important in order to understand and predict performance materials electrochemical applications. Here we present detailed X-ray absorption spectroscopy study two different tetrahedral amorphous-carbon (ta-C) thin films their subsequent characterization. The results show marked differences ta-C bulk properties, namely amount functional groups sp3/sp2 ratios, respectively. In particular, variation oxygen content...
Successful deployment of carbon nanomaterials in many applications, such as sensing, energy storage, and catalysis, relies on the selection, synthesis, tailoring surface properties. Predictive analysis behavior is difficult without detailed knowledge differences between various their functionalization, thus leaving selection process to traditional trial-and-error work. The present characterization fills this gap for nanomaterial properties with respect chemical states functionalization. We...
With their interesting electrical, structural, and physical properties, carbon nanotubes (CNTs) are envisioned to impact future nanoelectronics, nanosensors, nanophotonics. Current research development efforts in the growth of CNTs rely on time-consuming one-parameter-at-a-time approach, whereby marginal variations conditions from run-to-run experiments could result substantially different outcomes. Here we report a highly efficient combinatorial approach study effects catalysts underlying...
We present a novel approach for the room-temperature fabrication of conductive traces and their subsequent site-selective dielectric encapsulation use in flexible electronics. have developed an aerosol-assisted atmospheric pressure plasma-based deposition process efficiently depositing materials on substrates. Silver nanowire silicon dioxide coatings were deposited using this as demonstration. The paper substrate with silver nanowires exhibited very low change resistance upon 50 cycles...
This paper reports the first known investigation of power dissipation and electrical breakdown in aerosol-jet-printed (AJP) graphene interconnects. The performance aerosol-jet printed was characterized using Transmission Line Method (TLM). resistance decreased with increasing printing pass number (n); lowest sheet measured 1.5 kΩ/sq. for n = 50. role thermal (RTH) studied a combination thermometry infrared (IR) imaging. A simple lumped model ([Formula: see text]) COMSOL Multiphysics used to...
Graphene has proven to be useful in biosensing applications. However, one of the main hurdles with printed graphene-based electrodes is achieving repeatable electrochemical performance from electrode another. We have developed a consistent fabrication process control sheet resistance inkjet-printed graphene electrodes, thereby accomplishing performance. Herein, we investigated properties multilayered (MLG) fully (IJP) on flexible Kapton substrates. The were fabricated by inkjet printing...
We demonstrate the functionalization of single-walled carbon nanotubes (SWNTs) using a glow discharge for generating atomic or molecular radicals. A 30-s exposure to cold plasma H2 results in near-saturation coverage SWNT with hydrogen. Functionalization SWNTs hydrogen is confirmed by an infrared band at 2924 cm−1, characteristic C–H stretching mode. corresponding decrease ultraviolet absorption also observed, which due loss some conjugated C–C π bonds covered SWNTs.
There is a strong demand for bioanalytical techniques to rapidly detect protease activities with high sensitivity and specificity. This study reports an activity-based electrochemical method toward this goal. Nanoelectrode arrays (NEAs) fabricated embedded vertically aligned carbon nanofibers (VACNFs) are functionalized specific peptide substrates containing ferrocene (Fc) tag. The kinetic proteolysis curves measured continuously repeated ac voltammetry, from which the catalytic activity...