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Full-Text Articles in Engineering
Pursuing Excitonic Energy Transfer With Programmable Dna-Based Optical Breadboards, Divita Mathur, Sebastián A. Díaz, Niko Hildebrandt, Ryan D. Pensack, Bernard Yurke, Austin Biaggne, Lan Li, Joseph S. Melinger, Mario G. Ancona, William B. Knowlton, Igor L. Medintz
Pursuing Excitonic Energy Transfer With Programmable Dna-Based Optical Breadboards, Divita Mathur, Sebastián A. Díaz, Niko Hildebrandt, Ryan D. Pensack, Bernard Yurke, Austin Biaggne, Lan Li, Joseph S. Melinger, Mario G. Ancona, William B. Knowlton, Igor L. Medintz
Materials Science and Engineering Faculty Publications and Presentations
DNA nanotechnology has now enabled the self-assembly of almost any prescribed 3-dimensional nanoscale structure in large numbers and with high fidelity. These structures are also amenable to site-specific modification with a variety of small molecules ranging from drugs to reporter dyes. Beyond obvious application in biotechnology, such DNA structures are being pursued as programmable nanoscale optical breadboards where multiple different/identical fluorophores can be positioned with sub-nanometer resolution in a manner designed to allow them to engage in multistep excitonic energy-transfer (ET) via Förster resonance energy transfer (FRET) or other related processes. Not only is the ability to create such complex …
Exciton Delocalization In A Fully Synthetic Dna-Templated Bacteriochlorin Dimer, Olga A. Mass, Devan R. Watt, Lance K. Patten, Ryan D. Pensack, Jeunghoon Lee, Daniel B. Turner, Bernard Yurke, William B. Knowlton
Exciton Delocalization In A Fully Synthetic Dna-Templated Bacteriochlorin Dimer, Olga A. Mass, Devan R. Watt, Lance K. Patten, Ryan D. Pensack, Jeunghoon Lee, Daniel B. Turner, Bernard Yurke, William B. Knowlton
Materials Science and Engineering Faculty Publications and Presentations
A bacteriochlorophyll a (Bchla) dimer is a basic functional unit in the LH1 and LH2 photosynthetic pigment–protein antenna complexes of purple bacteria, where an ordered, close arrangement of Bchla pigments—secured by noncovalent bonding to a protein template—enables exciton delocalization at room temperature. Stable and tunable synthetic analogs of this key photosynthetic subunit could lead to facile engineering of exciton-based systems such as in artificial photosynthesis, organic optoelectronics, and molecular quantum computing. Here, using a combination of synthesis and theory, we demonstrate that exciton delocalization can be achieved in a dimer of a synthetic bacteriochlorin (BC …
High-Sensitivity Electronic Stark Spectrometer Featuring A Laser-Driven Light Source, J. S. Huff, K. M. Duncan, C. J. Van Galen, M. S. Barclay, W. B. Knowlton, B. Yurke, P. H. Davis, D. B. Turner, R. J. Stanley, R. D. Pensack
High-Sensitivity Electronic Stark Spectrometer Featuring A Laser-Driven Light Source, J. S. Huff, K. M. Duncan, C. J. Van Galen, M. S. Barclay, W. B. Knowlton, B. Yurke, P. H. Davis, D. B. Turner, R. J. Stanley, R. D. Pensack
Materials Science and Engineering Faculty Publications and Presentations
We report developmental details of a high-sensitivity Stark absorption spectrometer featuring a laser-driven light source. The light source exhibits intensity fluctuations of ∼0.3% over timescales ranging from 1 min to 12 h, minimal drift (≤ 0.1%/h), and very little 1/f noise at frequencies greater than 200 Hz, which are comparable to or better than an arc-driven light source. Additional features of the spectrometer include balanced detection with multiplex sampling, which yielded lower noise in A, and constant wavelength or wavenumber (energy) spectral bandpass modes. We achieve noise amplitudes of ∼7 × 10−4 and ∼6 × 10−6 …
Decoding The Hydrodynamic Properties Of Microscale Helical Propellers From Brownian Fluctuations, Bernard Yurke
Decoding The Hydrodynamic Properties Of Microscale Helical Propellers From Brownian Fluctuations, Bernard Yurke
Materials Science and Engineering Faculty Publications and Presentations
The complex motility of bacteria, ranging from single-swimmer behaviors such as chemotaxis to collective dynamics, including biofilm formation and active matter phenomena, is driven by their microscale propellers. Despite extensive study of swimming flagellated bacteria, the hydrodynamic properties of their helical-shaped propellers have never been directly measured. The primary challenges to directly studying microscale propellers are 1) their small size and fast, correlated motion, 2) the necessity of controlling fluid flow at the microscale, and 3) isolating the influence of a single propeller from a propeller bundle. To solve the outstanding problem of characterizing the hydrodynamic properties of these propellers, …
Effect Of Substituent Location On The Relationship Between The Transition Dipole Moments, Difference Static Dipole, And Hydrophobicity In Squaraine Dyes For Quantum Information Devices, Maia Ketteridge, Austin Biaggne, Ryan Rau, German Barcenas, Olga A. Mass, William B. Knowlton, Bernard Yurke, Lan Li
Effect Of Substituent Location On The Relationship Between The Transition Dipole Moments, Difference Static Dipole, And Hydrophobicity In Squaraine Dyes For Quantum Information Devices, Maia Ketteridge, Austin Biaggne, Ryan Rau, German Barcenas, Olga A. Mass, William B. Knowlton, Bernard Yurke, Lan Li
Materials Science and Engineering Faculty Publications and Presentations
Aggregates of organic dyes that exhibit excitonic coupling have a wide array of applications, including medical imaging, organic photovoltaics, and quantum information devices. The optical properties of a dye monomer, as a basis of dye aggregate, can be modified to strengthen excitonic coupling. Squaraine (SQ) dyes are attractive for those applications due to their strong absorbance peak in the visible range. While the effects of substituent types on the optical properties of SQ dyes have been previously examined, the effects of various substituent locations have not yet been investigated. In this study, density functional theory (DFT) and time-dependent density functional …
Molecular Dynamic Studies Of Dye–Dye And Dye–Dna Interactions Governing Excitonic Coupling In Squaraine Aggregates Templated By Dna Holliday Junctions, German Barcenas, Austin Biaggne, Olga A. Mass, William B. Knowlton, Bernard Yurke, Lan Li
Molecular Dynamic Studies Of Dye–Dye And Dye–Dna Interactions Governing Excitonic Coupling In Squaraine Aggregates Templated By Dna Holliday Junctions, German Barcenas, Austin Biaggne, Olga A. Mass, William B. Knowlton, Bernard Yurke, Lan Li
Materials Science and Engineering Faculty Publications and Presentations
Dye molecules, arranged in an aggregate, can display excitonic delocalization. The use of DNA scaffolding to control aggregate configurations and delocalization is of research interest. Here, we applied Molecular Dynamics (MD) to gain an insight on how dye–DNA interactions affect excitonic coupling between two squaraine (SQ) dyes covalently attached to a DNA Holliday junction (HJ). We studied two types of dimer configurations, i.e., adjacent and transverse, which differed in points of dye covalent attachments to DNA. Three structurally different SQ dyes with similar hydrophobicity were chosen to investigate the sensitivity of excitonic coupling to dye placement. Each dimer configuration was …
Probing Dna Structural Heterogeneity By Identifying Conformational Subensembles Of A Bicovalently Bound Cyanine Dye, Matthew S. Barclay, Azhad U. Chowdhury, Austin Biaggne, Jonathan S. Huff, Nicholas D. Wright, Paul H. Davis, Lan Li, William B. Knowlton, Bernard Yurke, Ryan D. Pensack, Daniel B. Turner
Probing Dna Structural Heterogeneity By Identifying Conformational Subensembles Of A Bicovalently Bound Cyanine Dye, Matthew S. Barclay, Azhad U. Chowdhury, Austin Biaggne, Jonathan S. Huff, Nicholas D. Wright, Paul H. Davis, Lan Li, William B. Knowlton, Bernard Yurke, Ryan D. Pensack, Daniel B. Turner
Materials Science and Engineering Faculty Publications and Presentations
DNA is a re-configurable, biological information-storage unit, and much remains to be learned about its heterogeneous structural dynamics. For example, while it is known that molecular dyes templated onto DNA exhibit increased photostability, the mechanism by which the structural dynamics of DNA affect the dye photophysics remains unknown. Here, we use femtosecond, two-dimensional electronic spectroscopy measurements of a cyanine dye, Cy5, to probe local conformations in samples of single-stranded DNA (ssDNA–Cy5), double-stranded DNA (dsDNA–Cy5), and Holliday junction DNA (HJ–DNA–Cy5). A line shape analysis of the 2D spectra reveals a strong excitation–emission correlation present in only the dsDNA–Cy5 complex, which is …
Tunable Electronic Structure Via Dna-Templated Heteroaggregates Of Two Distinct Cyanine Dyes, Jonathan S. Huff, Matthew S. Barclay, Azhad U. Chowdhury, Lance K. Patten, Simon K. Roy, Aaron Sup, Austin Biaggne, Lan Li, Jeunghoon Lee, Paul H. Davis, Bernard Yurke, William B. Knowlton, Daniel B. Turner, Ryan D. Pensack
Tunable Electronic Structure Via Dna-Templated Heteroaggregates Of Two Distinct Cyanine Dyes, Jonathan S. Huff, Matthew S. Barclay, Azhad U. Chowdhury, Lance K. Patten, Simon K. Roy, Aaron Sup, Austin Biaggne, Lan Li, Jeunghoon Lee, Paul H. Davis, Bernard Yurke, William B. Knowlton, Daniel B. Turner, Ryan D. Pensack
Materials Science and Engineering Faculty Publications and Presentations
Molecular excitons are useful for applications in light harvesting, organic optoelectronics, and nanoscale computing. Electronic energy transfer (EET) is a process central to the function of devices based on molecular excitons. Achieving EET with a high quantum efficiency is a common obstacle to excitonic devices, often owing to the lack of donor and acceptor molecules that exhibit favorable spectral overlap. EET quantum efficiencies may be substantially improved through the use of heteroaggregates─aggregates of chemically distinct dyes─rather than individual dyes as energy relay units. However, controlling the assembly of heteroaggregates remains a significant challenge. Here, we use DNA Holliday junctions to …
Molecular Dynamics Simulations Of Cyanine Dimers Attached To Dna Holliday Junctions, Austin Biaggne, Young C. Kim, Joseph S. Melinger, William B. Knowlton, Bernard Yurke, Lan Li
Molecular Dynamics Simulations Of Cyanine Dimers Attached To Dna Holliday Junctions, Austin Biaggne, Young C. Kim, Joseph S. Melinger, William B. Knowlton, Bernard Yurke, Lan Li
Materials Science and Engineering Faculty Publications and Presentations
Dye aggregates and their excitonic properties are of interest for their applications to organic photovoltaics, non-linear optics, and quantum information systems. DNA scaffolding has been shown to be effective at promoting the aggregation of dyes in a controllable manner. Specifically, isolated DNA Holliday junctions have been used to achieve strongly coupled cyanine dye dimers. However, the structural properties of the dimers and the DNA, as well as the role of Holliday junction isomerization are not fully understood. To study the dynamics of cyanine dimers in DNA, molecular dynamics simulations were carried out for adjacent and transverse dimers attached to Holliday …
Oblique Packing And Tunable Excitonic Coupling In Dna-Templated Squaraine Rotaxane Dimer Aggregates, Matthew S. Barclay, Christopher K. Wilson, Simon K. Roy, Olga A. Mass, Azhad U. Chowdhury, Jonathan S. Huff, Daniel B. Turner, Paul H. Davis, Bernard Yurke, William B. Knowlton, Jeunghoon Lee, Ryan D. Pensack
Oblique Packing And Tunable Excitonic Coupling In Dna-Templated Squaraine Rotaxane Dimer Aggregates, Matthew S. Barclay, Christopher K. Wilson, Simon K. Roy, Olga A. Mass, Azhad U. Chowdhury, Jonathan S. Huff, Daniel B. Turner, Paul H. Davis, Bernard Yurke, William B. Knowlton, Jeunghoon Lee, Ryan D. Pensack
Materials Science and Engineering Faculty Publications and Presentations
When molecules are aggregated such that their excited states form delocalized excitons, their spatial arrangement, or packing, can be coarsely controlled by templating and finely controlled by chemical substitution; however, challenges remain in controlling their packing on intermediate length scales. Here, we use an approach based on mechanically interlocked molecules to promote an elusive oblique packing arrangement in a series of three squaraine rotaxane dimers. We template the squaraine rotaxane dimers using DNA and observe two excitonically split bands of near-equal intensity in their absorption spectra – a distinct signature of oblique packing, validated by theoretical modeling of the experimental …
Characterizing Mode Anharmonicity And Huang–Rhys Factors Using Models Of Femtosecond Coherence Spectra, Matthew S. Barclay, Jonathan S. Huff, Ryan D. Pensack, Paul H. Davis, William B. Knowlton, Bernard Yurke, Jacob C. Dean, Paul C. Arpin, Daniel B. Turner
Characterizing Mode Anharmonicity And Huang–Rhys Factors Using Models Of Femtosecond Coherence Spectra, Matthew S. Barclay, Jonathan S. Huff, Ryan D. Pensack, Paul H. Davis, William B. Knowlton, Bernard Yurke, Jacob C. Dean, Paul C. Arpin, Daniel B. Turner
Materials Science and Engineering Faculty Publications and Presentations
Femtosecond laser pulses readily produce coherent quantum beats in transient–absorption spectra. These oscillatory signals often arise from molecular vibrations and therefore may contain information about the excited-state potential energy surface near the Franck–Condon region. Here, by fitting the measured spectra of two laser dyes to microscopic models of femtosecond coherence spectra (FCS) arising from molecular vibrations, we classify coherent quantum-beat signals as fundamentals or overtones and quantify their Huang–Rhys factors and anharmonicity values. We discuss the extracted Huang–Rhys factors in the context of quantum-chemical computations. This work solidifies the use of FCS for analysis of coherent quantum beats arising from …
Data-Driven And Multiscale Modeling Of Dna-Templated Dye Aggregates, Austin Biaggne, Lawrence Spear, German Barcenas, Maia Ketteridge, William B. Knowlton, Bernard Yurke, Lan Li
Data-Driven And Multiscale Modeling Of Dna-Templated Dye Aggregates, Austin Biaggne, Lawrence Spear, German Barcenas, Maia Ketteridge, William B. Knowlton, Bernard Yurke, Lan Li
Materials Science and Engineering Faculty Publications and Presentations
Dye aggregates are of interest for excitonic applications, including biomedical imaging, organic photovoltaics, and quantum information systems. Dyes with large transition dipole moments (μ) are necessary to optimize coupling within dye aggregates. Extinction coefficients (ε) can be used to determine the μ of dyes, and so dyes with a large ε (>150,000 M−1) should be engineered or identified. However, dye properties leading to a large ε are not fully understood, and low-throughput methods of dye screening, such as experimental measurements or density functional theory (DFT) calculations, can be time-consuming. In order to screen large datasets of molecules …
Tuning Between Quenching And Energy Transfer In Dna-Templated Heterodimer Aggregates, Azhad U. Chowdhury, Jonathan S. Huff, Matthew S. Barclay, Lance K. Patten, Aaron Sup, Natalya Hallstrom, Jeunghoon Lee, Paul H. Davis, Daniel B. Turner, Bernard Yurke, William B. Knowlton, Ryan D. Pensack
Tuning Between Quenching And Energy Transfer In Dna-Templated Heterodimer Aggregates, Azhad U. Chowdhury, Jonathan S. Huff, Matthew S. Barclay, Lance K. Patten, Aaron Sup, Natalya Hallstrom, Jeunghoon Lee, Paul H. Davis, Daniel B. Turner, Bernard Yurke, William B. Knowlton, Ryan D. Pensack
Materials Science and Engineering Faculty Publications and Presentations
Molecular excitons, which propagate spatially via electronic energy transfer, are central to numerous applications including light harvesting, organic optoelectronics, and nanoscale computing; they may also benefit applications such as photothermal therapy and photoacoustic imaging through the local generation of heat via rapid excited-state quenching. Here we show how to tune between energy transfer and quenching for heterodimers of the same pair of cyanine dyes by altering their spatial configuration on a DNA template. We assemble “transverse” and “adjacent” heterodimers of Cy5 and Cy5.5 using DNA Holliday junctions. We find that the transverse heterodimers exhibit optical properties consistent with excitonically interacting …
Exciton Delocalization In A Dna-Templated Organic Semiconductor Dimer Assembly, Xiao Wang, Ruojie Sha, William B. Knowlton, Nadrian C. Seeman, James W. Canary, Bernard Yurke
Exciton Delocalization In A Dna-Templated Organic Semiconductor Dimer Assembly, Xiao Wang, Ruojie Sha, William B. Knowlton, Nadrian C. Seeman, James W. Canary, Bernard Yurke
Materials Science and Engineering Faculty Publications and Presentations
A chiral dimer of an organic semiconductor was assembled from octaniline (octamer of polyaniline) conjugated to DNA. Facile reconfiguration between the monomer and dimer of octaniline–DNA was achieved. The geometry of the dimer and the exciton coupling between octaniline molecules in the assembly was studied both experimentally and theoretically. The octaniline dimer was readily switched between different electronic states by protonic doping and exhibited a Davydov splitting comparable to those previously reported for DNA–dye systems employing dyes with strong transition dipoles. This approach provides a possible platform for studying the fundamental properties of organic semiconductors with DNA-templated assemblies, which serve …
Excited-State Lifetimes Of Dna-Templated Cyanine Dimer, Trimer, And Tetramer Aggregates: The Role Of Exciton Delocalization, Dye Separation, And Dna Heterogeneity, Jonathan S. Huff, Daniel B. Turner, Olga A. Mass, Lance K. Patten, Christopher K. Wilson, Simon K. Roy, Matthew S. Barclay, Bernard Yurke, William B. Knowlton, Paul H. Davis, Ryan D. Pensack
Excited-State Lifetimes Of Dna-Templated Cyanine Dimer, Trimer, And Tetramer Aggregates: The Role Of Exciton Delocalization, Dye Separation, And Dna Heterogeneity, Jonathan S. Huff, Daniel B. Turner, Olga A. Mass, Lance K. Patten, Christopher K. Wilson, Simon K. Roy, Matthew S. Barclay, Bernard Yurke, William B. Knowlton, Paul H. Davis, Ryan D. Pensack
Materials Science and Engineering Faculty Publications and Presentations
DNA-templated molecular (dye) aggregates are a novel class of materials that have garnered attention in a broad range of areas including light harvesting, sensing, and computing. Using DNA to template dye aggregation is attractive due to the relative ease with which DNA nanostructures can be assembled in solution, the diverse array of nanostructures that can be assembled, and the ability to precisely position dyes to within a few Angstroms of one another. These factors, combined with the programmability of DNA, raise the prospect of designer materials custom tailored for specific applications. Although considerable progress has been made in characterizing the …
First-Principles Studies Of Substituent Effects On Squaraine Dyes, German Barcenas, Austin Biaggne, Olga A. Mass, Christopher K. Wilson, Ryan D. Pensack, Jeunghoon Lee, William B. Knowlton, Bernard Yurke, Lan Li
First-Principles Studies Of Substituent Effects On Squaraine Dyes, German Barcenas, Austin Biaggne, Olga A. Mass, Christopher K. Wilson, Ryan D. Pensack, Jeunghoon Lee, William B. Knowlton, Bernard Yurke, Lan Li
Materials Science and Engineering Faculty Publications and Presentations
Dye molecules that absorb light in the visible region are key components in many applications, including organic photovoltaics, biological fluorescent labeling, super-resolution microscopy, and energy transport. One family of dyes, known as squaraines, has received considerable attention recently due to their favorable electronic and photophysical properties. In addition, these dyes have a strong propensity for aggregation, which results in emergent materials properties, such as exciton delocalization. This will be of benefit in charge separation and energy transport along with fundamental studies in quantum information. Given the high structural tunability of squaraine dyes, it is possible that exciton delocalization could be …
An Alternative Approach To Nucleic Acid Memory, George D. Dickinson, Golam Md Mortuza, William Clay, Luca Piantanida, Christopher M. Green, Chad Watson, Eric J. Hayden, Tim Andersen, Wan Kuang, Elton Graugnard, Reza Zadegan, William L. Hughes
An Alternative Approach To Nucleic Acid Memory, George D. Dickinson, Golam Md Mortuza, William Clay, Luca Piantanida, Christopher M. Green, Chad Watson, Eric J. Hayden, Tim Andersen, Wan Kuang, Elton Graugnard, Reza Zadegan, William L. Hughes
Materials Science and Engineering Faculty Publications and Presentations
DNA is a compelling alternative to non-volatile information storage technologies due to its information density, stability, and energy efficiency. Previous studies have used artificially synthesized DNA to store data and automated next-generation sequencing to read it back. Here, we report digital Nucleic Acid Memory (dNAM) for applications that require a limited amount of data to have high information density, redundancy, and copy number. In dNAM, data is encoded by selecting combinations of single-stranded DNA with (1) or without (0) docking-site domains. When self-assembled with scaffold DNA, staple strands form DNA origami breadboards. Information encoded into the breadboards is read by …
Substituent Effects On The Solubility And Electronic Properties Of The Cyanine Dye Cy5: Density Functional And Time-Dependent Density Functional Theory Calculations, Austin Biaggne, William B. Knowlton, Bernard Yurke, Jeunghoon Lee, Lan Li
Substituent Effects On The Solubility And Electronic Properties Of The Cyanine Dye Cy5: Density Functional And Time-Dependent Density Functional Theory Calculations, Austin Biaggne, William B. Knowlton, Bernard Yurke, Jeunghoon Lee, Lan Li
Materials Science and Engineering Faculty Publications and Presentations
The aggregation ability and exciton dynamics of dyes are largely affected by properties of the dye monomers. To facilitate aggregation and improve excitonic function, dyes can be engineered with substituents to exhibit optimal key properties, such as hydrophobicity, static dipole moment differences, and transition dipole moments. To determine how electron donating (D) and electron withdrawing (W) substituents impact the solvation, static dipole moments, and transition dipole moments of the pentamethine indocyanine dye Cy5, density functional theory (DFT) and time-dependent (TD-) DFT calculations were performed. The inclusion of substituents had large effects on the solvation energy of Cy5, with pairs of …
Aerosol Jet Printed Capacitive Strain Gauge For Soft Structural Materials, Kiyo T. Fujimoto, Jennifer K. Watkins, Timothy Phero, Takoda Bingham, Kshama Lakshmi Ranganatha, Benjamin C. Johnson, Zhangxian Deng, Brian Jaques, David Estrada
Aerosol Jet Printed Capacitive Strain Gauge For Soft Structural Materials, Kiyo T. Fujimoto, Jennifer K. Watkins, Timothy Phero, Takoda Bingham, Kshama Lakshmi Ranganatha, Benjamin C. Johnson, Zhangxian Deng, Brian Jaques, David Estrada
Materials Science and Engineering Faculty Publications and Presentations
Soft structural textiles, or softgoods, are used within the space industry for inflatable habitats, parachutes and decelerator systems. Evaluating the safety and structural integrity of these systems occurs through structural health monitoring systems (SHM), which integrate non-invasive/non-destructive testing methods to detect, diagnose, and locate damage. Strain/load monitoring of these systems is limited while utilizing traditional strain gauges as these gauges are typically stiff, operate at low temperatures, and fail when subjected to high strain that is a result of high loading classifying them as unsuitable for SHM of soft structural textiles. For this work, a capacitance based strain gauge (CSG) …
High-Performance Flexible Bismuth Telluride Thin Film From Solution Processed Colloidal Nanoplates, Madhusudan Kongara, Tony Varghese, Karthik Chinnathambi, Jesse Schimpf, Josh Eixenberger, Paul H. Davis, Yaqiao Wu, David Estrada
High-Performance Flexible Bismuth Telluride Thin Film From Solution Processed Colloidal Nanoplates, Madhusudan Kongara, Tony Varghese, Karthik Chinnathambi, Jesse Schimpf, Josh Eixenberger, Paul H. Davis, Yaqiao Wu, David Estrada
Materials Science and Engineering Faculty Publications and Presentations
Thermoelectric generators are an environmentally friendly and reliable solid‐state energy conversion technology. Flexible and low‐cost thermoelectric generators are especially suited to power flexible electronics and sensors using body heat or other ambient heat sources. Bismuth telluride (Bi2Te3) based thermoelectric materials exhibit their best performance near room temperature making them an ideal candidate to power wearable electronics and sensors using body heat. In this report, Bi2Te3 thin films are deposited on a flexible polyimide substrate using low‐cost and scalable manufacturing methods. The synthesized Bi2Te3 nanocrystals have a thickness of 35 ± …
Fully Inkjet-Printed Multilayered Graphene-Based Flexible Electrodes For Repeatable Electrochemical Response, Twinkle Pandhi, Kiyo Fujimoto, Pete Barnes, Jasmine Cox, Hui Xiong, Paul H. Davis, Harish Subbaraman, David Estrada
Fully Inkjet-Printed Multilayered Graphene-Based Flexible Electrodes For Repeatable Electrochemical Response, Twinkle Pandhi, Kiyo Fujimoto, Pete Barnes, Jasmine Cox, Hui Xiong, Paul H. Davis, Harish Subbaraman, David Estrada
Materials Science and Engineering Faculty Publications and Presentations
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 one printed electrode to another. We have developed a consistent fabrication process to control the sheet resistance of inkjet-printed graphene electrodes, thereby accomplishing repeatable electrochemical performance. Herein, we investigated the electrochemical properties of multilayered graphene (MLG) electrodes fully inkjet-printed (IJP) on flexible Kapton substrates. The electrodes were fabricated by inkjet printing three materials – (1) a conductive silver ink for electrical contact, (2) an insulating dielectric ink, and (3) MLG ink as the sensing material. …
A Review Of Inkjet Printed Graphene And Carbon Nanotubes Based Gas Sensors, Twinkle Pandhi, Ashita Chandnani, Harish Subbaraman, David Estrada
A Review Of Inkjet Printed Graphene And Carbon Nanotubes Based Gas Sensors, Twinkle Pandhi, Ashita Chandnani, Harish Subbaraman, David Estrada
Materials Science and Engineering Faculty Publications and Presentations
Graphene and carbon nanotube (CNT)-based gas/vapor sensors have gained much traction for numerous applications over the last decade due to their excellent sensing performance at ambient conditions. Inkjet printing various forms of graphene (reduced graphene oxide or modified graphene) and CNT (single-wall nanotubes (SWNTs) or multiwall nanotubes (MWNTs)) nanomaterials allows fabrication onto flexible substrates which enable gas sensing applications in flexible electronics. This review focuses on their recent developments and provides an overview of the state-of-the-art in inkjet printing of graphene and CNT based sensors targeting gases, such as NO2, Cl2, CO2, NH3 …
Voices Of Our Students: Using Evidence-Based Methods To Inform A Multidisciplinary Engineering Program Design, Vicki Stieha, Noah Salzman, Amy J. Moll
Voices Of Our Students: Using Evidence-Based Methods To Inform A Multidisciplinary Engineering Program Design, Vicki Stieha, Noah Salzman, Amy J. Moll
Materials Science and Engineering Faculty Publications and Presentations
Listening carefully to our students and integrating the variables that matter to them is a step that we can take to increase the number of women and underrepresented minority graduates in engineering. This paper shares an evaluative case study as we report findings from data gathering tools guiding our continuous improvement process. The findings illuminate students’ perceptions of their engineering design course and curriculum. We conclude by discussing the pedagogical decisions the teaching team is making as a result of listening to our students’ voices.
Boron-Implanted Silicon Substrates For Physical Adsorption Of Dna Origami, Sadao Takabayashi, Shohei Kotani, Juan Flores-Estrada, Elijah Spears, Jennifer E. Padilla, Lizandra C. Godwin, Elton Graugnard, Wan Kuang, William L. Hughes
Boron-Implanted Silicon Substrates For Physical Adsorption Of Dna Origami, Sadao Takabayashi, Shohei Kotani, Juan Flores-Estrada, Elijah Spears, Jennifer E. Padilla, Lizandra C. Godwin, Elton Graugnard, Wan Kuang, William L. Hughes
Materials Science and Engineering Faculty Publications and Presentations
DNA nanostructures routinely self-assemble with sub-10 nm feature sizes. This capability has created industry interest in using DNA as a lithographic mask, yet with few exceptions, solution-based deposition of DNA nanostructures has remained primarily academic to date. En route to controlled adsorption of DNA patterns onto manufactured substrates, deposition and placement of DNA origami has been demonstrated on chemically functionalized silicon substrates. While compelling, chemical functionalization adds fabrication complexity that limits mask efficiency and hence industry adoption. As an alternative, we developed an ion implantation process that tailors the surface potential of silicon substrates to facilitate adsorption of DNA nanostructures …
Work In Progress: Flexibility And Professional Preparation Via A Multidisciplinary Engineering Curriculum, Noah Salzman, Vicki Stieha, Amy J. Moll, Joann S. Lighty
Work In Progress: Flexibility And Professional Preparation Via A Multidisciplinary Engineering Curriculum, Noah Salzman, Vicki Stieha, Amy J. Moll, Joann S. Lighty
Materials Science and Engineering Faculty Publications and Presentations
This paper reports on one institution’s work-in-progress to build innovation and creativity into a flexible, ABET accredited undergraduate Engineering B.S. degree that provides a variety of choices to undergraduate engineering students. The new Engineering Plus degree has a core set of required foundational courses in engineering, a multi-year design sequence, and allows for self-defined pathways. The new curriculum also offers three defined degree pathways that have been chosen based on an examination of student “fate” data: secondary education, pre-medical, and environmental studies, with additional pathways planned for the near future. The fate analysis examined the paths of students who were …
Metrology Of Dna Arrays By Super-Resolution Microscopy, Christopher M. Green, Kelly Schutt, Noah Morris, Reza M. Zadegan, William L. Hughes, Wan Kuang, Elton Graugnard
Metrology Of Dna Arrays By Super-Resolution Microscopy, Christopher M. Green, Kelly Schutt, Noah Morris, Reza M. Zadegan, William L. Hughes, Wan Kuang, Elton Graugnard
Materials Science and Engineering Faculty Publications and Presentations
Recent results in the assembly of DNA into structures and arrays with nanoscale features and patterns have opened the possibility of using DNA for sub-10 nm lithographic patterning of semiconductor devices. Super-resolution microscopy is being actively developed for DNA-based imaging and is compatible with inline optical metrology techniques for high volume manufacturing. Here, we combine DNA tile assembly with state-dependent super-resolution microscopy to introduce crystal-PAINT as a novel approach for metrology of DNA arrays. Using this approach, we demonstrate optical imaging and characterization of DNA arrays revealing grain boundaries and the temperature dependence of array quality. For finite arrays, analysis …
Availability: A Metric For Nucleic Acid Strand Displacement Systems, Xiaoping Olson, Shohei Kotani, Jennifer E. Padilla, Natalya Hallstrom, Sara Goltry, Jeunghoon Lee, Bernard Yurke, William L. Hughes, Elton Graugnard
Availability: A Metric For Nucleic Acid Strand Displacement Systems, Xiaoping Olson, Shohei Kotani, Jennifer E. Padilla, Natalya Hallstrom, Sara Goltry, Jeunghoon Lee, Bernard Yurke, William L. Hughes, Elton Graugnard
Materials Science and Engineering Faculty Publications and Presentations
DNA strand displacement systems have transformative potential in synthetic biology. While powerful examples have been reported in DNA nanotechnology, such systems are plagued by leakage, which limits network stability, sensitivity, and scalability. An approach to mitigate leakage in DNA nanotechnology, which is applicable to synthetic biology, is to introduce mismatches to complementary fuel sequences at key locations. However, this method overlooks nuances in the secondary structure of the fuel and substrate that impact the leakage reaction kinetics in strand displacement systems. In an effort to quantify the impact of secondary structure on leakage, we introduce the concepts of availability and …
Signal-To-Noise Ratio Enhancement Using Graphene-Based Passive Microelectrode Arrays, Sepideh Rastegar, Justin Stadlbauer, Kiyo Fujimoto, Kari Mclaughlin, David Estrada, Kurtis D. Cantley
Signal-To-Noise Ratio Enhancement Using Graphene-Based Passive Microelectrode Arrays, Sepideh Rastegar, Justin Stadlbauer, Kiyo Fujimoto, Kari Mclaughlin, David Estrada, Kurtis D. Cantley
Materials Science and Engineering Faculty Publications and Presentations
This work is aimed toward the goal of investigating the influence of different materials on the signal-to-noise ratio (SNR) of passive neural microelectrode arrays (MEAs). Noise reduction is one factor that can substantially improve neural interface performance. The MEAs are fabricated using gold, indium tin oxide (ITO), and chemical vapor deposited (CVD) graphene. 3D-printed Nylon reservoirs are then adhered to the glass substrates with identical MEA patterns. Reservoirs are filled equally with a fluid that is commonly used for neuronal cell culture. Signal is applied to glass micropipettes immersed in the solution, and response is measured on an oscilloscope from …
High-Performance And Flexible Thermoelectric Films By Screen Printing Solution-Processed Nanoplate Crystals, Tony Varghese, Courtney Hollar, Joseph Richardson, Nicholas Kempf, Chao Han, Pasindu Gamarachchi, David Estrada, Yanliang Zhang
High-Performance And Flexible Thermoelectric Films By Screen Printing Solution-Processed Nanoplate Crystals, Tony Varghese, Courtney Hollar, Joseph Richardson, Nicholas Kempf, Chao Han, Pasindu Gamarachchi, David Estrada, Yanliang Zhang
Materials Science and Engineering Faculty Publications and Presentations
Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate …
Determining Hydrodynamic Forces In Bursting Bubbles Using Dna Nanotube Mechanics, Rizal F. Hariadi, Erik Winfree, Bernard Yurke
Determining Hydrodynamic Forces In Bursting Bubbles Using Dna Nanotube Mechanics, Rizal F. Hariadi, Erik Winfree, Bernard Yurke
Materials Science and Engineering Faculty Publications and Presentations
Quantifying the mechanical forces produced by fluid flows within the ocean is critical to understanding the ocean’s environmental phenomena. Such forces may have been instrumental in the origin of life by driving a primitive form of self-replication through fragmentation. Among the intense sources of hydrodynamic shear encountered in the ocean are breaking waves and the bursting bubbles produced by such waves. On a microscopic scale, one expects the surface-tension–driven flows produced during bubble rupture to exhibit particularly high velocity gradients due to the small size scales and masses involved. However, little work has examined the strength of shear flow rates …