Swain Home

Greg Swain

We thank you for your interest in our research group at Michigan State University. We encourage you to explore this website to learn more about our interdisciplinary research and the students who are engaged in the projects.

Google Scholar: http://scholar.google.com/citations?user=WI4v_OoAAAAJ&hl=en

ResearchGate:https://www.researchgate.net/profile/Greg_Swain/info/?ev=prf_info

ResearcherID: B-302302010   http://www.researcherid.com/rid/B-3023-2010

ORCID: http://orcid.org/0000-0001-6498-8351

 

MSU Affiliations:

Director, Summer REU Program in Cross-Disciplinary Research in Sustainable Chemistry and Chemical Processes (2014 - present)

Graduate Program Director, Neuroscience Program (2017-present)

Education Coordinator - Responsible Conduct of Research, Scholarship and Creative Activities (RCRSCA), The Graduate School, MSU (2019-present)

Department of Chemical Engineering and Materials Science (Adjunct)

MSU Fraunhofer - Center for Coatings and Diamond Technologies

 

International Affiliations:

Japan Society for the Promotion of Science Short-Term Research Fellow (2020-2021)

Fulbright Scholar, Escuela Politécnica Nacional - Ecuador (2019-2020)

Fulbright Specialist - Czech Republic (2018)

Visiting Professor, Domaine Universitaire, Grenoble, France (summer 2001) 

Special Visiting Researcher (CAPES), Universidade Federal de São Carlos (Brazil), 2013-2016

 

Service:

Academic Advancement Network Leadership Fellow, MSU (2018-2019)

At-Large Member MSU Steering Committee (2017-2019)

At-Large Member MSU Faculty Senate (2017-2019)

At-Large Member MSU University Council (2017-2019)

ACS Committee on Professional Training, Member (2015-2020)

Editor, Electroanalysis (Wiley), 2019-present

Associate Editor, Critical Reviews in Analytical Chemistry, 2014-present

Advisory Board, Advanced Engineering Materials, 2014-present

Editor-in-Chief, Diamond and Related Materials, 2011-2014

Editor, Diamond and Related Materials, 2009-2011

Editorial Board, Diamond and Related Materials (Elsevier), 2006-2015


Research in our group is interdisciplinary in scope. We study electrochemical reaction kinetics, mechanisms, and interfacial processes at various types of carbon electrodes, including boron-doped diamond (BDD) and nitrogen-incorporated tetrahedral amorphous carbon (ta-C:N), before and after chemical modification. The research utilizes planar thin films, optically transparent electrodes, microelectrodes, and powderous forms of BDD and ta-C:N. A goal is to tailor the properties of these sp3 carbon electrodes for optimal application in chemical and biochemical sensors for health and the environment, microelectrodes for neuroanalytical chemistry, bioanalysis, and new materials for molecular separations. We also study electrochemical processes at aerospace aluminum alloys and investigate how different types of coating systems inhibit environmental corrosion. A variety of analytical tools are used in the research including electrochemical and spectroelectrochemical methods of analysis, electron and optical microscopy, optical profilometry, x-ray diffraction, x-ray photoelectron spectroscopy, and Raman spectroscopy. Finally, we develop new measurement methods using liquid chromatography (LC) and capillary zone electrophoresis (CZE), coupled with electrochemical detection, for important environmental and biological analytes.

We welcome the incoming graduate students in 2020-21! The following are current research projects available to interested students:

1. Diamond Microelectrode Fabrication and Application. This work is focused on developing chemical vapor deposition approaches for forming thin films of BDD conformally on Pt wires from 10 to 100 µm in diameter, investigating new insulation methods, and studying the electrochemical behavior of these microelectrodes using fast scan cyclic voltammetry. 

2. Neuroanalytical Chemistry. BDD microelectrodes and electrochemical methods are being used, along with pharmacological and molecular biology tools, to study excitatory (serotonin) and inhibitory (ATP and nitric oxide) neuromuscular signaling in vitro in the gastrointestinal tract of test animals for the purpose of learning about the mechanisms behind disruption of these signaling pathways in disease states. The current focus is on understanding how obesity affects these signaling pathways, and therefore gut function. A biosensor for ATP and a chemical sensor for nitric oxide are also employed in the work.

We are also interested in developing LC and CZE-EC methods, using BDD electrodes, for the analysis of electroactive neurosignaling molecules in whole tissue specimens from the small and large intestine. These projects are collaborative with colleagues in the Department of Pharmacology and Toxicology and Neuroscience Program. 

3. Measurements of Inflammatory Biomarkers in Exhaled Breath Condensate. The goal of this project is to develop a rapid, point-of-care diagnostic measurement platform that can noninvasively detect biomarkers of airway inflammation (nitric oxide and peroxynitrite) in exhaled breath condensate. Electrochemical sensors for nitric oxide and peroxynitrite are used in this work; both utilize a BDD microelectrode platform. Airway inflammation is associate with respiratory diseases and is particularly problematic in obliterative bronchiolitis after lung transplant, in patients with lung cancer undergoing chemotherapy, and cystic fibrosis. An objective of the project is to determine if the peroxynitrite/nitric oxide ratio is a useful, non-invasive indicator of airway inflammation. The project is collaborative with physicians in the College of Medicine (MSU).

4. Diagnostic Platform for Electrochemically Measuring Biomarkers of Infection in Animal Wounds. Research is being conducted to develop a point-of-care diagnostic platform that can be used to electrochemicially detect biomarkers of wound healing and infection. The technology development is currently focused on the rapid detection of pyocyanin; a metabolite secreted by the pathogen, Pseudomonas aeruginosa (PA). The measurements are made using wound swab specimens collected from injured dogs and cats being treated at the Small Animal Veterinary Medical Center on campus. Ink-jet printed carbon nanotube and nanographene electrodes are enabling materials for the platform and are provided as part of a collaboration with the University of Bologna (Italy).The project also involves collaboration with faculty in the Department of Microbiology and Molecular Genetics, and the College of Veterinary Medicine (MSU).

5. Heterogeneous Electrochemical Processes in Aqueous, Organic, and Ionic Liquid Electrolytes. Fundamental research is being conducted to learn how the surface chemical modification of BDD and ta-C:N thin-film electrodes affects molecular adsorption, capacitance, and electron-transfer kinetics for soluble redox molecules. The goal is to learn how the physical, chemical and electronic properties of the electrodes affect these interfacial electrochemical processes in different solvent/electrolyte systems. 

6. Preparation and Characterization of Electrically Conducting Diamond Powders.  A core-shell approach is being used to prepare high surface area, boron-doped ultrananocrystalline diamond-coated powders for application in electrochemical sensors and as a solid phase for molecular separations. These materials appear attractive for application as a stationary phase for solid phase extraction and for electrochemically-modulated liquid chromatography (EMLC). The same core-shell approach is being used to prepare metal-impregnated high surface area diamond powders for application in electrocatalysis. This work is, in part, collaborative with the University of Utah.

7. Advanced Coating Systems for Electrochemical Corrosion Control on Aerospace Aluminum Alloys. Basic and applied research is being conducted to learn how the alloy type, surface pretreatment, and coating chemistry affect how well environmentally-friendly, non-chromate coating systems inhibit electrochemical corrosion  on aerospace aluminum alloys. Some materials being tested are wrought alloys and others are prepared by advanced manufacturing processes (e.g., 3D printing). Surface pretreatments being studied include mechanical abrasion, chemical milling, solution processing, laser cleaning, and anodization. Analytical chemistry plays an important role in characterization of the alloy surface/coating interface, the coating thickness and chemistry, the mechanisms of electrochemical corrosion, and the initial stages of specimen degradation during different accelerated degradation test scenarios. This project involves a number of industrial partners.

 


Research Synopsis

Research in our group is interdisciplinary and spans several fields: physical and analytical electrochemistry, carbon materials, environmental analysis, bioanalysis, neuroanalytical chemistry and corrosion science. We conduct fundamental research with advanced carbon materials to address key problems and technological needs in energy, health and the environment. Our core science lies in the preparation, processing and application of diamond and diamond-like carbons. We seek to considerably improve the ability to prepare and control the material properties of single and polycrystalline diamond, and nitrogen-incorporated tetrahedral amorphous carbon, and to explore frontier applications where the unique material properties are essential for performance.

The following descriptions provide an overview of some of the ongoing and new research projects in the group.

Diamond Microelectrodes

There is a need to develop chemical vapor deposition approaches for forming thin films of BDD conformally on Pt wires from 10 to 100 µm in diameter, investigating new insulation methods, and studying the electrochemical behavior of these microelectrodes using fast scan cyclic voltammetry. A goal of this project is to determine how these microelectrodes perform in fast scan cyclic voltammetry measurements for various catecholamine neurotransmitters and other small soluble redox molecules. Coating BDD on 76 µm diameter Pt wires is straightforward. There are technical challenges to coating smaller diameter substrate wires that need to be overcome. These same microelectrodes will also be used in electrochemical detection coupled with CZE. The electron micrographs below show examples of BDD microelectrodes.

 

Amperometric Sensors and Biosensors for Health and the Environment

We are making use of nanostructured carbon materials and chemical functionalization strategies to develop a novel array of amperometric sensors and biosensors for use in human health. It is anticipated that the results derived from this research will provide several new and simple sensors that can be applied for important biomedical measurements in complex physiological samples.

The following sensors and biosensors are being developed for different applications:

1. Nitric oxide (NO) - This is an important enteric inhibitory neurosignaling molecule in the gastrointestinal tract. We are using this sensor in vitro to study how NO-mediated neuromuscular signaling is altered in obesity.

2. Peroxynitrite (PON) - This is an important marker of inflammation. We are using this sensor in vitro to probe for the presence of inflammation in the gut wall in obesity.

3. ATP - This is an important vasoconstricting neurotransmitter released from  sympathetic nerves that innervate blood vessels. It is also an enteric inhibitory neurotransmitter in the gut. We are using this biosensor in vitro to study how purinergic signaling in the vasculature and gut  is altered in obesity.

The NO and PON sensors are also part of a noninvasive analyzer being developed for exhaled breath and breath condensate. The goal of this project is to detect trace levels of these biomarkers of inflammation in exhaled breath. The innovative sensor-based technology could provide  on-site and point-of-care detection of these exhaled  biomarkers that are relevant in the management of asthma, cystic fibrosis, cancer and other respiratory diseases. This project is collaborative with faculty in the Departments of Medicine and the Lung Transplant Program. [Current funding = Clinical and Translational Sciences Institute, MSU]

Smart Bandages

An array of sensors is being developed using ink-jet printing technology for application in a “smart bandage”. The sensor system will report on the status of wound healing by measuring oxygen levels, pH, uric acid and toxins produced by infectious bacteria. The sensor array will also incorporate an electrode for electrogenerating oxidants to inactivate infectious bacteria, thus lessening the need for antibiotics. This project is collaborative with faculty in the Departments of Physiology, and Microbiology and Molecular Genetics, Small Animal Clinical Sciences (College of Veterinary Medicine, MSU) and EPFL (Switzerland).

 

Neuroelectrochemical Measurements in the Peripheral Vasculature and Gastrointestinal Tract

Neuroeffector transmission mechanisms differ depending on the target tissue. Abnormalities in signaling are associated with various diseases including hypertension and gastrointestinal disorders (e.g., IBS). We use diamond and carbon fiber microelectrodes along with in vitro electrochemical methods to investigate neuroeffector signaling in peripheral tissues. These measurements are useful for probing dynamic changes in concentration of an electroactive analyte in response to a stimulus. They also provide insight on the local neuropharmacology. Specifically, we are using these analytical methods to better understand the dysregulation that develops in obesity-associated (i) hypertension and (ii) gut dysmotility. Nearly 70% of American adults are either overweight or obese. Being obese puts one at a higher risk for diseases such as heart disease, stroke, high blood pressure, diabetes and more. Inexpensive conducting diamond is an enabling electrode material for these measurements because of its superior response sensitivity, reproducibility and stability in the complex tissue environment.

The target signaling molecules are (i) norepinephrine and ATP released from sympathetic nerves supplying arteries and or veins, (ii) serotonin released from enterochromaffin cells in the intestinal mucosa and (iii) nitric oxide and ATP released from inhibitory motor neurons in the gut. Tissues from animal models as well as humans are being used in the research. Immunohistochemical and pharmacological approaches, analytical separation methods and in vitro electrochemical methods are being employed to better understand these obesity-linked disorders. The projects are  collaborative with faculty in the Departments of Pharmacology and Toxicology. [Current funding = NIH].

 

Electrochemical Studies of Diamond and Tetrahedral Amorphous Carbon Thin-Film Electrodes - Comparisons in Aqueous Electrolytes and Room Temperature Ionic Liquids

We are investigating the interfacial structure, capacitance-potential profiles and the electron-transfer kinetics of soluble mediators in room temperature ionic liquids (RTILs). RTILs are emerging as a new class of “conducting” liquid with many important uses in electrochemistry. RTILs are composed of purely ions in the liquid state with no solvent. They generally have low volatility, high solubilizing power, good electrical and ionic conductivity, and are electrochemically stable (i.e., wide potential window).

It is well established that the surface cleanliness, microstructure and chemistry  affect electron-transfer kinetics at carbon electrodes. The heterogeneous electron-transfer rate constants for some redox systems are more strongly influenced by these variables in aqueous electrolyte solutions than are others. It is unclear if these variables affect electron-transfer kinetics in RTILs in the same manner. We are using conventional voltammetric measurements, digital simulations, electrochemical impedance spectroscopy and scanning electrochemical microscopy to study various redox systems at boron-doped diamond, tetrahedral amorphous carbon, glassy carbon and graphene electrodes. Bulk electrodes and thin films are being studied as are powderous (nanostructured) forms of the carbons. Various material characterization tools are being used to characterize the morphology, microstructure and surface chemistry of the electrodes including SEM/TEM, electrical measurements, contact angle measurements, XPS, XRD and Raman microprobe imaging. The goal of this work is to learn more about electron-transfer reactions in RTILs at different carbon electrodes and to correlate the physical, chemical and electronic properties of the electrodes with the heterogeneous electron-transfer reaction kinetics. [Current funding = Army Research Office].

Surface Pretreatments of Aluminum Alloys and Inorganic Coatings for Corrosion Prevention

A wide variety of materials are used in aerospace applications including light weight aluminum alloys, carbon fiber-epoxy composites, titanium alloys and steels. These materials, particularly the metals, are deployed with a multilayer coating system that provides corrosion protection. A typical coating system consists of a conversion coating, a primer and top coat. Understanding how to integrate these coatings in ways that minimize galvanic corrosion, pitting corrosion, and the resulting corrosion fatigue, is of paramount importance.

There are three primary goals driving the research: (i) replacement of the toxic Cr(VI)-containing coatings currently in use with more environmentally-friendly, non-chromate inorganic coatings (conversion coatings and primers), (ii) development of tetrahedral amorphous carbon (ta-C) coatings for contacting metal parts that offer both wear and corrosion resistance and (iii) understanding the degradation mechanisms of carbon fiber-epoxy composites when galvanically coupled. Students are studying and optimizing key processing parameters including (i) the method of application, (ii) substrate preparation (roughness, microstructure and chemistry), (iii) coating composition and structure, and (iv) post processing of the coating (aging and heat treatment).

Greater scientific insight regarding the fundamentals of corrosion and coating degradation during different accelerated degradation testing scenarios will lead to new materials, advanced coating systems, improved corrosion-prevention strategies, and thus better overall aerospace material performance. [Current funding = Office of Naval Research and Honeywell through the Department of Energy].

Nanostructured Diamond  Powders for Advanced Separations

High surface area, electrically-conducting and corrosion-resistant nanodiamond and nanodiamond/graphene composite powders are being prepared by chemical vapor deposition using a core-shell approach. Depending on the substrate used, the resulting powders can have surface areas in the 100-200 m2/g range and electrical conductivities greater than 0.5 S/cm.

In terms of separations, new research involves the use of these conducting powders as a stationary phase material in electrochemically-modulated liquid chromatography (EMLC). In this method, the stationary phase is made into a working electrode on the column and solute retention is studied as a function of the potential applied to the stationary phase and the temperature. EMLC is being used  to better understand (i) the double layer structure formed at these diamond powders in aqueous media and (ii) the thermodynamics of molecular (electrostatic) interactions with the carbon material surface. Powders with various chemical modification are being studied (e.g., H, O, NH2).

Diamond is an excellent material for use in chromatography because it is the hardest material on earth and it is stable under a wide range of temperatures and pH levels. In theory, diamond and functionalized diamond should offer superior performance to silica and functionalized silica. The inertness of diamond may allow it to be used with biologically-sensitive samples that are often pH sensitive and can easily foul a column. In addition, diamond-based stationary phases should allow for the exploration of novel chemistries. To this end, new research is exploring the use of micrometer diamond and functionalized diamond powders as a stationary phase for reversed- and normal-phase liquid chromatography. Potential exists to use diamond as a novel stationary phase for solid phase extractions (SPE).