Analytical Methods Blog

We are delighted to introduce our latest Analytical Methods Emerging Investigator, Alexander Zestos!

Alexander Zestos is a Greek-American from Williamsburg, VA. He completed a BS/MS degree in Chemistry from the College of William and Mary in Williamsburg, VA in 2008. There, he performed research with Dr. William H. Starnes, Jr. on the use of metal-clay additives and ester thiols to promote the smoke suppression, fire retrardance, and thermal stability of poly(vinyl chloride). He completed his PhD in Chemistry in 2014 at the University of Virginia, where he worked with Dr. Jill Venton and investigated the use of alternative carbon nanomaterials for enhanced neurochemical detection using fast scan cyclic voltammetry. From 2014-2017, he was a postdoctoral research fellow in the Departments of Chemistry and Pharmacology at the University of Michigan and was co-mentored by Professors Robert T. Kennedy and Margaret E. Gnegy. There, he developed microdialysis and liquid chromatography-mass spectrometry assays to measure neurochemical dynamics in rats after the administration of amphetamine and cocaine. He also developed the use of protein kinase C (PKC) inhibitors as novel therapeutics for amphetamine abuse in addition to measuring acetylcholine release from beige fat adipocytes and the neurochemical biomarkers of epileptic seizures. Since 2017, he is an Assistant Professor in the Department of Chemistry and Center for Behavioral Neuroscience at American University in Washington, D.C., where he develops electrochemical methods and electrode materials to enhance neurotransmitter detection for a wide variety of applications.

Read Alexander’s Emerging Investigator series paper “Polymer modified carbon fiber-microelectrodes and waveform modifications enhance neurotransmitter metabolite detection” and find out more about him in the interview below:

Your recent Emerging Investigator Series paper focuses on carbon-fiber microelectrodes and waveform modifications for the detection of neurotransmitter metabolites. How has your research evolved from your first article to this most recent article?
My research has evolved greatly over time. As a BS/MS student at the College of William and Mary, I investigated the development of smoke suppressants, fire retardants, and thermal stabilizers for poly(vinyl chloride). As a PhD student at the University of Virginia, I became more interested in research that could be used for biomedical applications. I utilized alternative carbon nanomaterials as electrodes for enhanced neurochemical detection with fast scan cyclic voltammetry (FSCV). As a postdoctoral research fellow in the Departments of Chemistry and Pharmacology at the University of Michigan, I used in vivo microdialysis coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect multiple neurotransmitters in vivo and measure the effects of PKC inhibitors on amphetamine-stimulated dopamine efflux. We were able to measure over 30 neurochemicals simultaneously in freely behaving animals, which had many applications for studying drugs of abuse, obesity, and epilepsy. At American University, I am combining the use of voltammetry, HPLC, and other methods to enhance neurochemical detection that is applicable to studying the effects of many drugs and behavioural states.

What aspect of your work are you most excited about at the moment?
I am excited by many projects. Currently, we are developing methods of neurochemical enhancement with carbon fiber-microelectrodes to study neurochemical dynamics in diabetic zebrafish and the effect of cathinone bath salts in rats. Moreover, we are also using carbon nanomaterials such as carbon nanotube yarns and polymer coatings to enhance neurochemical sensitivity, temporal resolution, and promote anti-fouling properties. My research continues to be at the interface of materials science, analytical measurements, and biomedical applications.

In your opinion, what are the key design considerations for developing novel electrode materials and waveforms for the detection of biomolecules?
The key design considerations for developing novel electrode materials and waveforms are to tune the electrode material selectively to each respective analyte. For this paper, we applied positively charged polymer coatings and removed the negative holding potential in order to enhance DOPAC detection, which is negatively charged at a physiological pH. The detection of other analytes such as dopamine, serotonin, norepinephrine, and others can be enhanced with other coatings and waveform modifications that are specific to each neurotransmitter being detected taking into account size, charge, chemical structure, and other considerations.

What do you find most challenging about your research?
In my opinion, the most challenging part of my research is continuous trial and error and overall complexity. However, this can also be the most rewarding aspect of research when an unexpected discovery is made. Reproducibility is also key in making and testing microelectrodes to measure neurochemical dynamics in small brain regions.

How do you spend your spare time?
I enjoy the outdoors, sports, traveling, and spending time with my family.

Which profession would you choose if you were not a scientist?
I most likely would be a physician or diplomat. I always considered myself to by a people-person and enjoy traveling, which is a big part of being a scientist.

Can you share one piece of career-related advice or wisdom with other early career scientists?
I would recommend pursuing your passion, yet being able to adapt to new circumstances, and to be continually persistent in your work. There will always be ups and downs in your research, but it is important to remain focused on the long-term goals of your career.

We are delighted to introduce our latest Analytical Methods Emerging Investigator, Charles Mace!

Dr Charles Mace earned his BS from Le Moyne College in 2003, followed by an MS (2006) and PhD (2008) from the University of Rochester in the laboratory of Prof. Benjamin Miller. He was then a postdoctoral scholar in the laboratory of Prof. George Whitesides at Harvard University from 2008–2011. Prior to joining the faculty at Tufts in 2013, he was a senior scientist at Diagnostics For All. Charlie is the Vice Chair for the upcoming 2020 Gordon Research Conference on Bioanalytical Sensors.

Read Charles’s Emerging Investigator series paper “Determination of sample stability for whole blood parameters using formal experimental design” and find out more about him in the interview below:

Your recent Emerging Investigator Series paper focuses on determination of sample stability for whole blood parameters. How has your research evolved from your first article to this most recent article?
Whether you’re asking about my first article as a graduate student or as PI, I have been fortunate to have a consistent scientific narrative in my career—creating technologies that can lead to improved access to healthcare. In graduate school at the University of Rochester, I developed a label-free, optical biosensor platform that I was applying to, among other things, characterizing the immune response to flu infections to help create improved vaccines. My first article on that technology described a sensor to detect pathogenic E. coli. In comparison to what my lab at Tufts University works on now (paper-based microfluidic devices), it was all very high tech. My first independent article described a new paper-based device architecture that could be used to perform immunoassays. It can be thought of as being analogous to a lateral flow test, but something that could be integrated more readily into the kinds of point-of-care hematology devices that we are pursuing. Some of that work is seen in this article.

What aspect of your work are you most excited about at the moment?
Can I say everything? I’m like a kid in a candy store when it comes to the research that is going on in our lab right now. We have projects related to point-of-care diagnostics, tissue engineering, materials science, and more. We are very collaborative with groups at Tufts and other universities and institutions, and we like being able to bring our expertise to many different areas of research. Being able to jump back and forth between these projects (and support and mentor the students leading these efforts) keeps my enthusiasm level high on a day-to-day basis. Ultimately, it is a major goal of my independent career to develop something “real” — an assay or device that other people can actually use. I think that we are close to that goal on multiple fronts.

In your opinion, what are the key design considerations for developing diagnostic assays for biological parameters?
We like to start with the end goal in mind: what does the user need? This answer is partly related to typical parameters like the desired sensitivity and specificity of the assay, but includes a number of other concerns too. Costs are always an obvious issue when the assay is intended for use in limited-resource settings. While we try to be as economical as possible, academics are actually really bad at estimating what the price of a test will be from the costs required to develop them. A consideration that we have been really focusing on lately is how devices will be used. For example, we try to understand how to increase the capabilities of our devices to make them easier to use and minimize the number of steps a user will need to perform to conduct the test. Not only are those concerns practical and driven by conversations with potential users, but they also end up generating interesting research ideas.

What do you find most challenging about your research?
Blood is deceptively difficult to handle and analyze, which is unlike other biofluids that I have studied in the past like serum, oral fluid, or urine. Blood is a dynamic, living sample whose properties change over time. Understanding these challenges and identifying strategies to effectively account for them are the first steps to developing assays or devices to analyze blood. Particularly with our goals to create point-of-care hematology tests, like with our paper-based hematocrit assay, having a sample that was varying over time could influence how we interpret results and make experimental decisions. Since we need large volumes of blood to develop tests, we mainly rely on local vendors to supply our blood. It’s very fresh, but not “fingerstick” fresh. We would require many many fingers to support our work! Honestly, that was the genesis of this manuscript. Lara (the first author on this paper) identified a problem that could affect her research objectives, devised a plan to understand the variables leading to instability of her blood samples, and demonstrated their impact in a clear way. These are challenges worth solving because the impact of this kind of point-of-care device could be felt worldwide. We have to get a lot of things right at this stage of the research.

How do you spend your spare time?
These days, my main hobbies are chasing around my toddler, teaching him proper animal noises (he’s nailed bear and whale, but can’t quite get sheep), and going to swim class with him. In our quieter moments at night, my wife and I really enjoy cooking together. Sometimes, we will even make competitions out of it by limiting ingredients or forcing together certain combinations of ingredients. It’s a different way of being creative, lets us try new foods, and it helps us share a common passion. Watching reruns of The Office (American version!) for the fifth time is also a common passion.

Which profession would you choose if you were not a scientist?
I actually started college with the goal of becoming a high school history teacher. Even though those plans changed really quickly, teaching and communicating have always been passions of mine. That being said, I would probably start a microbrewery with my wife that made great IPAs and tater tots.

Can you share one piece of career-related advice or wisdom with other early career scientists?
I love this job and it is ultimately very rewarding, but it can be difficult, overwhelming, and potentially even lonely at times. That is particularly true when you are just starting out and trying to find your voice. Surround yourself with colleagues and mentors that can provide support and guidance. And remember to willingly offer that support to others! You don’t need to go through it alone just to prove your ‘independence’. This is just as true for graduate students as it is seasoned PIs.