Papers by Christian Zorman
This paper presents the design, fabrication and characterization of a wireless capacitive pressur... more This paper presents the design, fabrication and characterization of a wireless capacitive pressure sensor with directional RF chip antenna that is envisioned for the health monitoring of aircraft engines operating in harsh environments. The sensing system is characterized from room temperature (25ºC) to 300°C for a pressure range from 0 to 100 psi. The wireless pressure system consists of a Clapp-type oscillator design with a capacitive MEMS pressure sensor located in the LC-tank circuit of the oscillator. Therefore, as the pressure of the aircraft engine changes, so does the output resonant frequency of the sensing system. A chip antenna is integrated to transmit the system output to a receive antenna 10 m away. The design frequency of the wireless pressure sensor is 127 MHz and a 2% increase in resonant frequency over the temperature range of 25 to 300 ºC from 0 to 100 psi is observed. The phase noise is less than-30 dBc/Hz at the 1 kHz offset and decreases to less than-80 dBc/Hz at 10 kHz over the entire temperature range. The RF radiation patterns for two cuts of the wireless system have been measured and show that the system is highly directional and the MEMS pressure sensor is extremely linear from 0 to 100 psi. KEYWORDS Wireless capacitive pressure sensor system, MEMS, chip antenna, passive and active components, high temperature applications, health monitoring.
Springer eBooks, 2010
Microelectromechanical systems (MEMS) have played key roles in many important areas, for example ... more Microelectromechanical systems (MEMS) have played key roles in many important areas, for example transportation, communication, automated manufacturing, environmental monitoring, health care, defense systems, and a wide range of consumer products. MEMS are inherently small, thus offering attractive characteristics such as reduced size, weight, and power dissipation and improved speed and precision compared to their macroscopic counterparts. Integrated circuit (IC) fabrication technology has been the primary enabling technology for MEMS besides a few special etching, bonding and assembly techniques. Microfabrication provides a powerful tool for batch processing and miniaturizing electromechanical devices and systems to a dimensional scale that is not accessible by conventional machining techniques. As IC fabrication technology continues to scale toward deep submicrometer and nanometer feature sizes, a variety of nanoelectromechanical systems (NEMS) can be envisioned in the foreseeable future. Nanoscale mechanical devices and systems integrated with nanoelectronics will open a vast number of new exploratory research areas in science and engineering. NEMS will most likely serve as an enabling technology, merging engineering with the life sciences in ways that are not currently feasible with microscale tools and technologies.
2017 IEEE 30th International Conference on Micro Electro Mechanical Systems (MEMS), 2017
This digest paper reports on the first demonstration of suspended β-Ga<inf>2</inf>O&l... more This digest paper reports on the first demonstration of suspended β-Ga<inf>2</inf>O<inf>3</inf> nanostructures and nanomechanical resonators made from single-crystal β-Ga<inf>2</inf>O<inf>3</inf> nanosheets or nanomembranes grown via low pressure chemical vapor deposition (LPCVD) on 3C-SiC epi-layer on Si substrate. These single-crystal β-Ga<inf>2</inf>O<inf>3</inf> drumhead nanomechanical resonators offer robust multimode resonances at frequencies in the range of ∼10 to 70MHz. The resonators exposed to middle ultraviolet (MUV) radiation exhibit shifts in resonant frequency with a responsivity of −3.8Hz/pW.
2021 21st International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers), 2021
The development of flexible electrodes has garnered heightened interest by the wearables communit... more The development of flexible electrodes has garnered heightened interest by the wearables community for monitoring and treating human health and performance in a non-invasive and unobtrusive manner. There remains a gap in developing absorbent, biocompatible, flexible, and scalable electrodes for wearable applications. To address this shortcoming, we developed a carbon black-polyvinyl alcohol (CB-PVA) nanocomposite electrode. Glycerol was used to facilitate hydrogen bonding and crosslink the nanocomposite. The material provides high flexibility, electrical conductivity, and demonstrates electrical stability over a long-term duration (5 hours). This simple and cost-effective fabrication method for CB-PVA nanocomposites provides an opportune pathway for various applications in the bioelectronics field.
Talanta, 2018
The analysis of protein-nucleic acid interactions is essential for biophysics related research. H... more The analysis of protein-nucleic acid interactions is essential for biophysics related research. However, simple, rapid, and accurate methods for biomolecules interaction analysis are lacking. We herein establish an electrochemical biosensor approach for protein-nucleic acid binding analysis. The fabrication method of a highly-controlled, inkjet printing and plasma based nanoparticle sensor is presented. A novel bioconjugation method is demonstrated as a simple and rapid approach for protein-based biosensor fabrication. As a proof of concept, we analyzed the binding interaction between unwinding protein 1 (UP1) and SL3 ESS3 RNA, confirming the accuracy of this nanoparticle based electrochemical biosensor approach with traditional biophysical methods. We further accurately profiled and differentiated a unique binding interaction pattern of multiple G-tract nucleic acid sequences with heterogeneous nuclear ribonucleoprotein H1. Our study provides insights into a potential universal platform for in vitro biomolecule interaction analysis based on an electrochemical biosensor approach.
Silicon Carbide Microelectromechanical Systems for Harsh Environments, 2006
Page 30. CHAPTER 2 DEPOSITION TECHNIQUES FOR SIC MEMS Christian A. Zorman, Xiao-An Fu and Mehran ... more Page 30. CHAPTER 2 DEPOSITION TECHNIQUES FOR SIC MEMS Christian A. Zorman, Xiao-An Fu and Mehran Mehregany Department of Electrical Engineering and Computer Science Case Western Reserve University Cleveland, Ohio 44106 USA E-mail: caz@ po. cwru. ...
Annals of biomedical engineering, 2015
Ideally, all chronic wounds would be prevented as they can become life threatening complications.... more Ideally, all chronic wounds would be prevented as they can become life threatening complications. The concept that a wound produces a 'current of injury' due to the discontinuity in the electrical field of intact skin provides the basis for the concept that electrical stimulation (ES) may provide an effective treatment for chronic wounds. The optimal stimulation waveform parameters are unknown, limiting the reliability of achieving a successful clinical therapeutic outcome. In order to gain a more thorough understanding of ES for chronic wound therapy, systematic evaluation using a valid in vivo model is required. The focus of the current paper is development of the flexible modular surface stimulation (MSS) device by our group. This device can be programed to deliver a variety of clinically relevant stimulation paradigms and is essential to facilitate systematic in vivo studies. The MSS version 2.0 for small animal use provides all components of a single-channel, programmab...
ECS Transactions, 2014
Smart Sensor Systems that can operate at high temperatures are required for a range of aerospace ... more Smart Sensor Systems that can operate at high temperatures are required for a range of aerospace applications including propulsion systems. This paper discusses the development and demonstration of the components of a high temperature Smart Sensor System that includes a sensor, electronics, wireless communication, and power scavenging. In particular, a wireless pressure sensor system was demonstrated at 475°C with a notable amount of the power provided by power scavenging at elevated temperatures. This wireless pressure sensor system included a sensor, electronics, and wireless communication components integrated onto a single alumina substrate. High temperature wireless signal transmission at a distance of 1 meter using this approach was demonstrated at 475º C from 70-100 psi for more than one hour. This demonstration of multiple Smart Sensor System components is considered a foundation for the development of high temperature Smart Sensor Systems for use in harsh environments.
IEEE Journal of Translational Engineering in Health and Medicine
Objective: Wound dressings that create and maintain a moist environment provide the optimal condi... more Objective: Wound dressings that create and maintain a moist environment provide the optimal conditions for wound healing by increasing the rate of epithelialization and angiogenesis. However, current wound dressings require periodic removal which exposes the wound to the surrounding environment, thereby increasing the likelihood for infection and drying out the wound itself. There remains an unmet medical need for the development of an absorbent, flexible, and transparent wound dressing that can conform to the irregular geometry of the wound for a long-term duration. Herein, we report the development of AFTIDerm, an Absorbent, Flexible, Transparent, and Inexpensive moisture-management wound dressing using Polyvinyl alcohol (PVA) as the host material. Methods: AFTIDerm substrates of varying glycerol concentrations (1 wt%, 3 wt%, 5 wt%, 7 wt%, and 10 wt%) were fabricated and tested. The mechanical, absorption, and biological properties of AFTIDerm were evaluated. Results: We found that 5% glycerol served as the optimal concentration for AFTIDerm. The biocompatibility, absorptive capabilities, and scalability render PVA/glycerol an ideal material composition for wound dressings. Benchtop experimentation and pre-clinical testing demonstrate AFTIDerm as a platform for use in wound dressings. Discussion/Conclusion: The development of AFTIDerm broadens the translational utility of this materials platform not only as a material for wound dressings to minimize dressing changes in low to moderate exudate environments, but also as a potential substrate material for smart bandages. INDEX TERMS Body fluid management, flexible substrates, polyvinyl alcohol, translational research, wound dressings. Clinical and Translational Impact Statement-AFTIDerm, an absorbent, flexible, and transparent wound dressing, maintains the moist environment required for healing while enabling monitoring of healing without removal and disruption to the wound bed.
This paper reports the development of mechanically-flexible, polycrystalline diamond-on-polymer e... more This paper reports the development of mechanically-flexible, polycrystalline diamond-on-polymer electrodes for use as neural interfaces. Boron-doped diamond has a number of properties that are attractive for use as electrodes in neural recording, stimulation, and electrochemical sensing. However, because the growth of polycrystalline diamond by chemical vapor deposition requires high temperatures (>800ºC), diamond thin films cannot be directly deposited on polymer substrates. To address this limitation, a transfer process was developed to incorporate diamond electrodes onto a polymer substrate. It was demonstrated that the diamondon-polymer devices made using this transfer process retain the mechanical properties of the polymer. Electrical characterization showed that the diamond electrodes have an impedance of ~2-3 M at 1 kHz. This and other tests indicate that the diamond-onpolymer electrodes have suitable characteristics for neural recording and stimulation.
Crystal Growth & Design, 2016
This paper presents the synthesis of single crystalline, selfcatalytic β-Ga 2 O 3 rods by a low p... more This paper presents the synthesis of single crystalline, selfcatalytic β-Ga 2 O 3 rods by a low pressure chemical vapor deposition technique. The effects of oxygen concentration and growth temperature on the morphology and growth rate of β-Ga 2 O 3 rods were studied. The β-Ga 2 O 3 rods were synthesized on a 3C-SiC film deposited on a silicon substrate utilizing high purity gallium (Ga) metal and oxygen (O 2) as source materials, and argon (Ar) as a carrier gas. X-ray diffraction, high resolution transmission electron microscopy, and Raman spectroscopy measurements were performed for the as-grown β-Ga 2 O 3 rods, which revealed a monoclinic phase of β-Ga 2 O 3 with single crystalline microstructure. The selected area electron diffraction pattern recorded on a single β-Ga 2 O 3 rod further verified their single crystalline nature. Because of their high crystalline quality and large surface area to volume ratio, these β-Ga 2 O 3 rods have a great potential for surface related applications such as photocatalysis, chemical sensing, and deep-ultraviolet photodetection.
Frontiers in Optics / Laser Science, 2018
Journal of Vacuum Science & Technology A, 2018
Printable metal inks are typically composed of premade nanoparticles that require postdeposition ... more Printable metal inks are typically composed of premade nanoparticles that require postdeposition thermal sintering to produce crystalline, electrically-conductive features. In this paper, we show that particle-free Ag inks made from simple, water-soluble metal salts such as silver nitrate can be ink-jet printed and converted into electrical features with tunable resistivity at low temperature (<100 o C) by exposure to a pure argon plasma. X-ray diffraction confirms that the converted inks are crystalline and four-point probe electrical measurements show that the sheet resistances are a function of the pressure and
2018 IEEE Biomedical Circuits and Systems Conference (BioCAS), 2018
Applied Physics Letters, 2011
Two cubic, single crystal silicon carbide ͑3C-SiC͒ films with similar thickness are shown to exhi... more Two cubic, single crystal silicon carbide ͑3C-SiC͒ films with similar thickness are shown to exhibit significantly different optical properties at mid-infrared wavelengths. Depth profiling by time-of-flight secondary ion mass spectroscopy indicates that these two films have substantially different n-type impurity concentrations that are responsible for the observed differences in optical absorption. The influence of impurities manifests as substantially different planar defect morphologies.
Journal of laboratory automation, 2012
Surface charge characterization is important in the design and testing of coatings and membranes ... more Surface charge characterization is important in the design and testing of coatings and membranes for biological and industrial applications, but commercial zeta potential meters are expensive and difficult to adapt to a variety of membrane designs. We combined inexpensive off-the-shelf components, a test mount fabricated with a conventional rapid prototyping system, and software written using a no-cost integrated development environment to implement a low-cost, automated streaming potential meter. Software written in Visual C# managed a USB data acquisition and control pod to regulate the transmembrane pressure while simultaneously reading transmembrane voltages from a digital multimeter with 0.1-nV precision. The streaming potential was measured through a commercially available polyethersulfone membrane with repeatable results for transmembrane pressures between -15 and 15 kPa. The transmembrane voltages for each set of six pressures were linear, with R (2) values greater than 0.99...
Journal of Applied Physics, 1995
Silicon carbide (Sic) films have been grown on 4 in, diam (100) silicon wafers by atmospheric pre... more Silicon carbide (Sic) films have been grown on 4 in, diam (100) silicon wafers by atmospheric pressure chemical vapor deposition, using propane, silane, and hydrogen. X-ray photoelectron spectroscopy data confirm that the films are stoichiometric Sic, with no major impurities. X-...
AJP: Renal Physiology, 2010
The role electrical charge plays in determining glomerular permeability to macromolecules remains... more The role electrical charge plays in determining glomerular permeability to macromolecules remains unclear. If the glomerular basement membrane (GBM) has any significant role in permselectivity, physical principles would suggest a negatively charged GBM would reject similarly charged more than neutral species. However, recent in vivo studies with negative and neutral glomerular probes showed the opposite. Whether this observation is due to unique characteristics of the probes used or is a general physiological phenomenon remains to be seen. The goal of this study was to use the basement membrane deposited by Madin-Darby canine kidney epithelial cells as a simple model of a biologically derived, negatively charged filter to evaluate size- and charge-based sieving properties. Fluorescein isothiocyanate-labeled carboxymethylated Ficoll 400 (FITC-CM Ficoll 400) and amino-4-methyl-coumarin-labeled Ficoll 400 (AMC Ficoll 400) were used as negatively charged and neutral tracer molecules, re...
AJP: Renal Physiology, 2010
The physiology of glomerular permselectivity remains mechanistically obscure, despite its importa... more The physiology of glomerular permselectivity remains mechanistically obscure, despite its importance in human disease. Although electrical contributions to glomerular permselectivity have long been considered important, two recent reports demonstrated enhanced glomerular permeability to anionic versus neutral polysaccharides. The interpretation of these observations is complicated by confounding of the effects of chemical modification on charge with effects on size and shape. In this report, neutral and anionic Ficoll are characterized by size-exclusion chromatography with online light scattering and viscometry and filtration through a highly defined anionic filtration membrane. Neutral and carboxymethylated Ficoll are nearly identical in size and conformation, yet carboxymethylated Ficoll is retained by an anionic membrane in excess of neutral Ficoll. This suggests that comparisons between clearances of neutral and carboxymethylated Ficoll may be a sensitive probe of electrostatic ...
Nanotechnology, 2006
A highly effective electrothermal tuning method is demonstrated for Al-SiC nanomechanical resonat... more A highly effective electrothermal tuning method is demonstrated for Al-SiC nanomechanical resonators. Doubly clamped beam devices are actuated and read out using a magnetomotive technique under a moderate vacuum at room temperature. Direct current applied to a beam heats the structure and shifts the resonance frequency downward. Frequency shifts of 10% are easily achievable, and the thermal time constant of these structures is in the submicrosecond range. The initial frequency and frequency tunability are studied for beams of varying Al thickness, and the device performance can be accurately modelled using simple mechanical and thermal models. Because of the different mechanical properties of SiC and Al, both the initial frequency and the frequency tunability can be modified by varying the Al layer thickness. This approach has the potential to become an important tool for effective frequency tuning in deployable SiC-based nanoelectromechanical system devices and systems for applications that would benefit from SiC as the structural material.
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Papers by Christian Zorman