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Full-Text Articles in Nanoscience and Nanotechnology

Stamped Multilayer Graphene Laminates For Disposable In-Field Electrodes: Application To Electrochemical Sensing Of Hydrogen Peroxide And Glucose, Loreen R. Stromberg, John A. Hondred, Delaney Sanborn, Deyny Mendivelso-Perez, Srikanthan Ramesh, Iris V. Rivero, Josh Kogot, Emily Smith, Carmen Gomes, Jonathan C. Claussen Jul 2019

Stamped Multilayer Graphene Laminates For Disposable In-Field Electrodes: Application To Electrochemical Sensing Of Hydrogen Peroxide And Glucose, Loreen R. Stromberg, John A. Hondred, Delaney Sanborn, Deyny Mendivelso-Perez, Srikanthan Ramesh, Iris V. Rivero, Josh Kogot, Emily Smith, Carmen Gomes, Jonathan C. Claussen

Jonathan C. Claussen

A multi-step approach is described for the fabrication of multi-layer graphene-based electrodes without the need for ink binders or post-print annealing. Graphite and nanoplatelet graphene were chemically exfoliated using a modified Hummers’ method and the dried material was thermally expanded. Expanded materials were used in a 3D printed mold and stamp to create laminate electrodes on various substrates. The laminates were examined for potential sensing applications using model systems of peroxide (H2O2) and enzymatic glucose detection. Within the context of these two assay systems, platinum nanoparticle electrodeposition and oxygen plasma treatment were examined as methods for improving sensitivity. Electrodes made ...


Porous Wood Monoliths Decorated With Platinum Nano-Urchins As Catalysts For Underwater Micro-Vehicle Propulsion Via H2o2 Decomposition, Bolin Chen, Ahmed Gsalla, Anand Gaur, Yu Hui Lui, Xiaohui Tang, Jason Geder, Marius Pruessner, Brian J. Melde, Igor L. Medintz, Behrouz Shafei, Shan Hu, Jonathan C. Claussen Jun 2019

Porous Wood Monoliths Decorated With Platinum Nano-Urchins As Catalysts For Underwater Micro-Vehicle Propulsion Via H2o2 Decomposition, Bolin Chen, Ahmed Gsalla, Anand Gaur, Yu Hui Lui, Xiaohui Tang, Jason Geder, Marius Pruessner, Brian J. Melde, Igor L. Medintz, Behrouz Shafei, Shan Hu, Jonathan C. Claussen

Jonathan C. Claussen

Porous carbon is becoming an important and promising high-surface area scaffold material for various energy-based applications including catalysis. Here we demonstrate the growth of urchin-like platinum nanoparticles (PtNPs) on carbon monoliths derived from basswood that work as catalysts for micro underwater vehicle (MUV) propulsion via H2O2 decomposition. The carbon monoliths were constructed of natural basswood that was carbonized in argon (Ar) and subjected to a subsequent CO2 activation process that rendered the material into a hardened 3D porous activated carbonized wood (ACW) with inner channel voids measuring 10-70 μm in diameter. The PtNP nanourchins (500 nm or less in total ...


Enhanced Electrochemical Biosensor And Supercapacitor With 3d Porous Architectured Graphene Via Salt Impregnated Inkjet Maskless Lithography, John A. Hondred, Igor L. Medintz, Jonathan C. Claussen Feb 2019

Enhanced Electrochemical Biosensor And Supercapacitor With 3d Porous Architectured Graphene Via Salt Impregnated Inkjet Maskless Lithography, John A. Hondred, Igor L. Medintz, Jonathan C. Claussen

Jonathan C. Claussen

Advances in solution-phase graphene patterning has provided a facile route for rapid, low-cost and scalable manufacturing of electrochemical devices, even on flexible substrates. While graphene possesses advantageous electrochemical properties of high surface area and fast heterogenous charge transport, these properties are attributed to the edge planes and defect sites, not the basal plane. Herein, we demonstrate enhancement of the electroactive nature of patterned solution-phase graphene by increasing the porosity and edge planes through the construction of a multidimensional architecture via salt impregnated inkjet maskless lithography (SIIML) and CO2 laser annealing. Various sized macroscale pores (<25 to ∼250 μm) are patterned directly in the graphene surface by incorporating porogens (i.e., salt crystals) in the ...


Flexible Laser-Induced Graphene For Nitrogen Sensing In Soil, Nate T. Garland, Eric S. Mclamore, Nicholas D. Cavallaro, Deyny Mendivelso-Perez, Emily A. Smith, Dapeng Jing, Jonathan C. Claussen Oct 2018

Flexible Laser-Induced Graphene For Nitrogen Sensing In Soil, Nate T. Garland, Eric S. Mclamore, Nicholas D. Cavallaro, Deyny Mendivelso-Perez, Emily A. Smith, Dapeng Jing, Jonathan C. Claussen

Jonathan C. Claussen

Flexible graphene electronics are rapidly gaining interest, but their widespread implementation has been impeded by challenges with ink preparation, ink printing, and post-print annealing processes. Laser-induced graphene (LIG) promises a facile alternative by creating flexible graphene electronics on polyimide substrates through a one-step laser writing fabrication method. Herein we demonstrate the use of LIG, created through a low-cost UV laser, for electrochemical ion selective sensing of plant-available nitrogen (i.e., both ammonium and nitrate ions: NH4+ and NO3-) in soil samples. The laser used to create the LIG was operated at distinct pulse rates (10, 20, 30, 40, and 50 ...


Cip2a Immunosensor Comprised Of Vertically-Aligned Carbon Nanotube Interdigitated Electrodes Towards Point-Of-Care Oral Cancer Screening, Shaowei Ding, Suprem R. Das, Benjamin J. Brownlee, Kshama Parate, Taylor Davis, Loreen Stromberg, Edward K.L. Chan, Joseph Katz, Brian D. Iverson, Jonathan C. Claussen Apr 2018

Cip2a Immunosensor Comprised Of Vertically-Aligned Carbon Nanotube Interdigitated Electrodes Towards Point-Of-Care Oral Cancer Screening, Shaowei Ding, Suprem R. Das, Benjamin J. Brownlee, Kshama Parate, Taylor Davis, Loreen Stromberg, Edward K.L. Chan, Joseph Katz, Brian D. Iverson, Jonathan C. Claussen

Jonathan C. Claussen

Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered much attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDE is functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—a salivary oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant immunosensor is capable ...


Enhanced Enzymatic Activity From Phosphotriesterase Trimer Gold Nanoparticle Bioconjugates For Pesticide Detection, John A. Hondred, Joyce C. Breger, Nate T. Garland, Eunkeu Oh, Kimihiro Susumu, Scott A. Walper, Igor L. Medintz, Jonathan C. Claussen Apr 2018

Enhanced Enzymatic Activity From Phosphotriesterase Trimer Gold Nanoparticle Bioconjugates For Pesticide Detection, John A. Hondred, Joyce C. Breger, Nate T. Garland, Eunkeu Oh, Kimihiro Susumu, Scott A. Walper, Igor L. Medintz, Jonathan C. Claussen

Jonathan C. Claussen

The rapid detection of organophosphates (OPs), a class of strong neurotoxins, is critically important for monitoring acute insecticide exposure and potential chemical warfare agent use. Herein, we improve the enzymatic activity of a phosphotriesterase trimer (PTE3), an enzyme that selectively recognizes OPs directly, by conjugation with distinctly sized (i.e., 5, 10, and 20 nm diameter) gold nanoparticles (AuNPs). The number of enzymes immobilized on the AuNP was controlled by conjugating increasing molar ratios of PTE3 onto the AuNP surface via metal affinity coordination. This occurs between the PTE3-His6 termini and the AuNP-displayed Ni2+-nitrilotriacetic acid end groups and was ...


Printed Graphene Electrochemical Biosensors Fabricated By Inkjet Maskless Lithography For Rapid And Sensitive Detection Of Organophosphates, John A. Hondred, Joyce C. Breger, Nathan J. Alves, Scott A. Trammell, Scott A. Walper, Igor L. Medintz, Jonathan C. Claussen Mar 2018

Printed Graphene Electrochemical Biosensors Fabricated By Inkjet Maskless Lithography For Rapid And Sensitive Detection Of Organophosphates, John A. Hondred, Joyce C. Breger, Nathan J. Alves, Scott A. Trammell, Scott A. Walper, Igor L. Medintz, Jonathan C. Claussen

Jonathan C. Claussen

Solution phase printing of graphene-based electrodes has recently become an attractive low-cost, scalable manufacturing technique to create in-field electrochemical biosensors. Here we report a graphene-based electrode developed via Inkjet Maskless Lithography (IML) for the direct and rapid monitoring of triple-O linked phosphonate organophosphates (OPs); these constitute the active compounds found in chemical warfare agents and pesticides that exhibit acute toxicity as well as long-term pollution to soils and waterways. The IML printed graphene electrode is nano/microstructured with a 1000 mW benchtop laser engraver and electrochemically deposited platinum nanoparticles (dia. ~25 nm) to improve its electrical conductivity (sheet resistance decreased ...


A Paper Based Graphene-Nanocauliflower Hybrid Composite For Point Of Care Biosensing, S. L. Burrs, R. Sidhu, M. Bhargava, J. Kieman-Lewis, N. Schwalb, Y. Rong, Carmen Gomes, Jonathan C. Claussen, D. C. Vanegas, E. S. Mclamore Mar 2018

A Paper Based Graphene-Nanocauliflower Hybrid Composite For Point Of Care Biosensing, S. L. Burrs, R. Sidhu, M. Bhargava, J. Kieman-Lewis, N. Schwalb, Y. Rong, Carmen Gomes, Jonathan C. Claussen, D. C. Vanegas, E. S. Mclamore

Jonathan C. Claussen

Graphene paper has diverse applications in printed circuit board electronics, bioassays, 3D cell culture, and biosensing. Although development of nanometal-graphene hybrid composites is commonplace in the sensing literature, to date there are only a few examples of nanometal-decorated graphene paper for use in biosensing. In this manuscript, we demonstrate the synthesis and application of Pt nano cauliflower-functionalized graphene paper for use in electrochemical biosensing of small molecules (glucose, acetone, methanol) or detection of pathogenic bacteria (Escherichia coli O157:H7). Raman spectroscopy, scanning electron microscopy and energy dispersive spectroscopy were used to show that graphene oxide deposited on nanocellulose crystals was ...


Platinum Nanoparticle Decorated Sio2 Microfibers As Catalysts For Micro Unmanned Underwater Vehicle Propulsion, Bolin Chen, Nathaniel T. Garland, Jason Geder, Marius Pruessner, Eric Mootz, Allison Cargill, Anne Leners, Granit Vokshi, Jacob Davis, Wyatt Burns, Michael A. Daniele, Josh Kogot, Igor L. Medintz, Jonathan C. Claussen Jun 2017

Platinum Nanoparticle Decorated Sio2 Microfibers As Catalysts For Micro Unmanned Underwater Vehicle Propulsion, Bolin Chen, Nathaniel T. Garland, Jason Geder, Marius Pruessner, Eric Mootz, Allison Cargill, Anne Leners, Granit Vokshi, Jacob Davis, Wyatt Burns, Michael A. Daniele, Josh Kogot, Igor L. Medintz, Jonathan C. Claussen

Jonathan C. Claussen

Micro unmanned underwater vehicles (UUVs) need to house propulsion mechanisms that are small in size but sufficiently powerful to deliver on-demand acceleration for tight radius turns, burst-driven docking maneuvers, and low-speed course corrections. Recently, small-scale hydrogen peroxide (H2O2) propulsion mechanisms have shown great promise in delivering pulsatile thrust for such acceleration needs. However, the need for robust, high surface area nanocatalysts that can be manufactured on a large scale for integration into micro UUV reaction chambers is still needed. In this report, a thermal/electrical insulator, silicon oxide (SiO2) microfibers, is used as a support for platinum nanoparticle (PtNP) catalysts ...


Increasing The Activity Of Immobilized Enzymes With Nanoparticle Conjugation, Shaowei Ding, Allison A. Cargill, Igor L. Medintz, Jonathan C. Claussen Mar 2017

Increasing The Activity Of Immobilized Enzymes With Nanoparticle Conjugation, Shaowei Ding, Allison A. Cargill, Igor L. Medintz, Jonathan C. Claussen

Jonathan C. Claussen

The efficiency and selectivity of enzymatic catalysis is useful to a plethora of industrial and manufacturing processes. Many of these processes require the immobilization of enzymes onto surfaces, which has traditionally reduced enzyme activity. However, recent research has shown that the integration of nanoparticles into enzyme carrier schemes has maintained or even enhanced immobilized enzyme performance. The nanoparticle size and surface chemistry as well as the orientation and density of immobilized enzymes all contribute to the enhanced performance of enzyme–nanoparticle conjugates. These improvements are noted in specific nanoparticles including those comprising carbon (e.g., graphene and carbon nanotubes), metal ...


Platinum Nanoparticle Decorated Sio2 Microfibers As Catalysts For Micro Unmanned Underwater Vehicle Propulsion, Bolin Chen, Nathaniel T. Garland, Jason Geder, Marius Pruessner, Eric Mootz, Allison Cargill, Anne Leners, Granit Vokshi, Jacob Davis, Wyatt Burns, Michael A. Daniele, Josh Kogot, Igor L. Medintz, Jonathan C. Claussen Mar 2017

Platinum Nanoparticle Decorated Sio2 Microfibers As Catalysts For Micro Unmanned Underwater Vehicle Propulsion, Bolin Chen, Nathaniel T. Garland, Jason Geder, Marius Pruessner, Eric Mootz, Allison Cargill, Anne Leners, Granit Vokshi, Jacob Davis, Wyatt Burns, Michael A. Daniele, Josh Kogot, Igor L. Medintz, Jonathan C. Claussen

Jonathan C. Claussen

Micro unmanned underwater vehicles (UUVs) need to house propulsion mechanisms that are small in size but sufficiently powerful to deliver on-demand acceleration for tight radius turns, burst-driven docking maneuvers, and low-speed course corrections. Recently, small-scale hydrogen peroxide (H2O2) propulsion mechanisms have shown great promise in delivering pulsatile thrust for such acceleration needs. However, the need for robust, high surface area nanocatalysts that can be manufactured on a large scale for integration into micro UUV reaction chambers is still needed. In this report, a thermal/electrical insulator, silicon oxide (SiO2) microfibers, is used as a support for platinum nanoparticle (PtNP) catalysts ...


High Aspect Ratio Carbon Nanotube Membranes Decorated With Pt Nanoparticle Urchins For Micro Underwater Vehicle Propulsion Via H2o2 Decomposition, Kevin Marr, Bolin Chen, Eric J. Mootz, Jason Geder, Marius Pruessner, Brian J. Melde, Richard R. Vanfleet, Igor L. Medintz, Brian D. Iverson, Jonathan C. Claussen Sep 2015

High Aspect Ratio Carbon Nanotube Membranes Decorated With Pt Nanoparticle Urchins For Micro Underwater Vehicle Propulsion Via H2o2 Decomposition, Kevin Marr, Bolin Chen, Eric J. Mootz, Jason Geder, Marius Pruessner, Brian J. Melde, Richard R. Vanfleet, Igor L. Medintz, Brian D. Iverson, Jonathan C. Claussen

Jonathan C. Claussen

The utility of unmanned micro underwater vehicles (MUVs) is paramount for exploring confined spaces, but their spatial agility is often impaired when maneuvers require burst-propulsion. Herein we develop high-aspect ratio (150:1), multiwalled carbon nanotube microarray membranes (CNT-MMs) for propulsive, MUV thrust generation by the decomposition of hydrogen peroxide (H2O2). The CNT-MMs are grown via chemical vapor deposition with diamond shaped pores (nominal diagonal dimensions of 4.5 × 9.0 μm) and subsequently decorated with urchin-like, platinum (Pt) nanoparticles via a facile, electroless, chemical deposition process. The Pt-CNT-MMs display robust, high catalytic ability with an effective activation energy of 26 ...


Probing The Enzymatic Activity Of Alkaline Phosphatase Within Quantum Dot Bioconjugates, Jonathan C. Claussen, Anthony Malanoski, Joyce C. Breger, Eunkeu Oh, Scott A. Walper, Kimihiro Susumu, Ramasis Goswami, Jeffrey R. Deschamps, Igor L. Medintz Dec 2014

Probing The Enzymatic Activity Of Alkaline Phosphatase Within Quantum Dot Bioconjugates, Jonathan C. Claussen, Anthony Malanoski, Joyce C. Breger, Eunkeu Oh, Scott A. Walper, Kimihiro Susumu, Ramasis Goswami, Jeffrey R. Deschamps, Igor L. Medintz

Jonathan C. Claussen

Enzymes provide the critical means by which to catalyze almost all biological reactions in a controlled manner. Methods to harness and exploit their properties are of strong current interest to the growing field of biotechnology. In contrast to depending upon recombinant genetic approaches, a growing body of evidence suggests that apparent enzymatic activity can be enhanced when located at a nanoparticle interface. We use semiconductor quantum dots (QDs) as a well-defined and easily bioconjugated nanoparticle along with Escherichia coli-derived alkaline phosphatase (AP) as a prototypical enzyme to seek evidence for this process in a de novo model system. We began ...


Nanomaterial-Mediated Biosensors For Monitoring Glucose, Eric S. Mclamore, Masashige Taguchi, Andre Ptitsyn, Jonathan C. Claussen Dec 2013

Nanomaterial-Mediated Biosensors For Monitoring Glucose, Eric S. Mclamore, Masashige Taguchi, Andre Ptitsyn, Jonathan C. Claussen

Jonathan C. Claussen

Real-time monitoring of physiological glucose transport is crucial for gaining new understanding of diabetes. Many techniques and equipment currently exist for measuring glucose, but these techniques are limited by complexity of the measurement, requirement of bulky equipment, and low temporal/spatial resolution. The development of various types of biosensors (eg, electrochemical, optical sensors) for laboratory and/or clinical applications will provide new insights into the cause(s) and possible treatments of diabetes. State-of-the-art biosensors are improved by incorporating catalytic nanomaterials such as carbon nanotubes, graphene, electrospun nanofibers, and quantum dots. These nanomaterials greatly enhance biosensor performance, namely sensitivity, response time ...


Complex Logic Functions Implemented With Quantum Dot Bionanophotonic Circuits, Jonathan C. Claussen, Niko Hildebrandt, Kimihiro Susumu, Mario G. Ancona, Igor L. Medintz Dec 2013

Complex Logic Functions Implemented With Quantum Dot Bionanophotonic Circuits, Jonathan C. Claussen, Niko Hildebrandt, Kimihiro Susumu, Mario G. Ancona, Igor L. Medintz

Jonathan C. Claussen

We combine quantum dots (QDs) with long-lifetime terbium complexes (Tb), a near-IR Alexa Fluor dye (A647), and self-assembling peptides to demonstrate combinatorial and sequential bionanophotonic logic devices that function by time-gated Förster resonance energy transfer (FRET). Upon excitation, the Tb-QD-A647 FRET-complex produces time-dependent photoluminescent signatures from multi-FRET pathways enabled by the capacitor-like behavior of the Tb. The unique photoluminescent signatures are manipulated by ratiometrically varying dye/Tb inputs and collection time. Fluorescent output is converted into Boolean logic states to create complex arithmetic circuits including the half-adder/half-subtractor, 2:1 multiplexer/1:2 demultiplexer, and a 3-digit, 16-combination keypad ...


Biophotonic Logic Devices Based On Quantum Dots And Temporally-Staggered Forster Energy Transfer Relays, Jonathan C. Claussen, W. Russ Algar, Niko Hildebrandt, Kimihiro Susumu, Mario G. Ancona, Igor L. Medintz Dec 2012

Biophotonic Logic Devices Based On Quantum Dots And Temporally-Staggered Forster Energy Transfer Relays, Jonathan C. Claussen, W. Russ Algar, Niko Hildebrandt, Kimihiro Susumu, Mario G. Ancona, Igor L. Medintz

Jonathan C. Claussen

Integrating photonic inputs/outputs into unimolecular logic devices can provide significantly increased functional complexity and the ability to expand the repertoire of available operations. Here, we build upon a system previously utilized for biosensing to assemble and prototype several increasingly sophisticated biophotonic logic devices that function based upon multistep Förster resonance energy transfer (FRET) relays. The core system combines a central semiconductor quantum dot (QD) nanoplatform with a long-lifetime Tb complex FRET donor and a near-IR organic fluorophore acceptor; the latter acts as two unique inputs for the QD-based device. The Tb complex allows for a form of temporal ...


Bacterial Isolation By Lectin-Modified Microengines, Susana Campuzano, Jahir Orozco, Daniel Kagan, Maria Guix, Wei Gao, Sirilak Sattayasamitsathit, Jonathan C. Claussen, Arben Merkoci, Joseph Wang Dec 2011

Bacterial Isolation By Lectin-Modified Microengines, Susana Campuzano, Jahir Orozco, Daniel Kagan, Maria Guix, Wei Gao, Sirilak Sattayasamitsathit, Jonathan C. Claussen, Arben Merkoci, Joseph Wang

Jonathan C. Claussen

New template-based self-propelled gold/nickel/polyaniline/platinum (Au/Ni/PANI/Pt) microtubular engines, functionalized with the Concanavalin A (ConA) lectin bioreceptor, are shown to be extremely useful for the rapid, real-time isolation of Escherichia coli (E. coli) bacteria from fuel-enhanced environmental, food, and clinical samples. These multifunctional microtube engines combine the selective capture of E. coli with the uptake of polymeric drug-carrier particles to provide an attractive motion-based theranostics strategy. Triggered release of the captured bacteria is demonstrated by movement through a low-pH glycine-based dissociation solution. The smaller size of the new polymer-metal microengines offers convenient, direct, and label-free optical ...


Electrochemical Glutamate Biosensing With Nanocube And Nanosphere Augmented Single-Walled Carbon Nanotube Networks: A Comparative Study, Jonathan C. Claussen, Mayra S. Artiles, Eric S. Mclamore, Subhashree Mohanty, Jin Shi, Jenna L. Rickus, Timothy S. Fisher, D. Marshall Porterfield Dec 2010

Electrochemical Glutamate Biosensing With Nanocube And Nanosphere Augmented Single-Walled Carbon Nanotube Networks: A Comparative Study, Jonathan C. Claussen, Mayra S. Artiles, Eric S. Mclamore, Subhashree Mohanty, Jin Shi, Jenna L. Rickus, Timothy S. Fisher, D. Marshall Porterfield

Jonathan C. Claussen

We describe two hybrid nanomaterial biosensor platforms, based on networks of single-walled carbon nanotubes (SWCNTs) enhanced with Pd nanocubes and Pt nanospheres and grown in situ from a porous anodic alumina (PAA) template. These nanocube and nanosphere SWCNT networks are converted into glutamate biosensors by immobilizing the enzyme glutamate oxidase (cross-linked with gluteraldehyde) onto the electrode surface. The Pt nanosphere/SWCNT biosensor outperformed the Pd nanocube/SWCNT biosensor and previously reported similar nanomaterial-based biosensors by amperometrically monitoring glutamate concentrations with a wide linear sensing range (50 nM to 1.6 mM) and a small detection limit (4.6 nM, 3s ...


A Self Referencing Platinum Nanoparticle Decorated Enzyme-Based Microbiosensor For Real Time Measurement Of Physiological Glucose Transport, Eric S. Mclamore, J. Shi, D. Jaroch, Jonathan C. Claussen, A. Uchida, Y. Jiang, Y. Zhang, S. S. Donkin, M. K. Banks, K. K. Buhman, D. Teegarden, Jenna L. Rickus, D. Marshall Porterfield Dec 2010

A Self Referencing Platinum Nanoparticle Decorated Enzyme-Based Microbiosensor For Real Time Measurement Of Physiological Glucose Transport, Eric S. Mclamore, J. Shi, D. Jaroch, Jonathan C. Claussen, A. Uchida, Y. Jiang, Y. Zhang, S. S. Donkin, M. K. Banks, K. K. Buhman, D. Teegarden, Jenna L. Rickus, D. Marshall Porterfield

Jonathan C. Claussen

Glucose is the central molecule in many biochemical pathways, and numerous approaches have
been developed for fabricating micro biosensors designed to measure glucose concentration in/
near cells and/or tissues. An inherent problem for microsensors used in physiological studies is a
low signal-to-noise ratio, which is further complicated by concentration drift due to the metabolic
activity of cells. A microsensor technique designed to filter extraneous electrical noise and provide
direct quantification of active membrane transport is known as self-referencing. Self-referencing
involves oscillation of a single microsensor via computer-controlled stepper motors within a stable
gradient formed near cells/tissues (i.e ...


Effects Of Carbon Nanotube-Tethered Nanosphere Density On Amperometric Biosensing: Simulation And Experiment, Jonathan C. Claussen, James B. Hengenius, Monique M. Wickner, Timothy S. Fisher, David M. Umulis, D. Marshall Porterfield Dec 2010

Effects Of Carbon Nanotube-Tethered Nanosphere Density On Amperometric Biosensing: Simulation And Experiment, Jonathan C. Claussen, James B. Hengenius, Monique M. Wickner, Timothy S. Fisher, David M. Umulis, D. Marshall Porterfield

Jonathan C. Claussen

Nascent nanofabrication approaches are being applied to reduce electrode feature dimensions from the microscale to the nanoscale, creating biosensors that are capable of working more efficiently at the biomolecular level. The development of nanoscale biosensors has been driven largely by experimental empiricism to date. Consequently, the precise positioning of nanoscale electrode elements is typically neglected, and its impact on biosensor performance is subsequently overlooked. Herein, we present a bottom-up nanoelectrode array fabrication approach that utilizes low-density and horizontally oriented single-walled carbon nanotubes (SWCNTs) as a template for the growth and precise positioning of Pt nanospheres. We further develop a computational ...


Microbiosensors Based On Dna Modified Single-Walled Carbon Nanotube And Pt Black Nanocomposites, Jin Shi, Tae-Gon Cha, Jonathan C. Claussen, Alfred R. Diggs, Jong Hyun Choi, D. Marshall Porterfield Dec 2010

Microbiosensors Based On Dna Modified Single-Walled Carbon Nanotube And Pt Black Nanocomposites, Jin Shi, Tae-Gon Cha, Jonathan C. Claussen, Alfred R. Diggs, Jong Hyun Choi, D. Marshall Porterfield

Jonathan C. Claussen

Glucose and ATP biosensors have important applications in diagnostics and research. Biosensors based on conventional materials suffer from low sensitivity and low spatial resolution. Our previous work has shown that combining single-walled carbon nanotubes (SWCNTs) with Pt nanoparticles can significantly enhance the performance of electrochemical biosensors. The immobilization of SWCNTs on biosensors remains challenging due to the aqueous insolubility originating from van der Waals forces. In this study, we used single-stranded DNA (ssDNA) to modify SWCNTs to increase solubility in water. This allowed us to explore new schemes of combining ssDNA-SWCNT and Pt black in aqueous media systems. The result ...