PLOS ONE recently published a new Collection of research entitled Recent Advances in Understanding Plastic Pollution. Given the broad scope of this…
In July, we updated our Nanomaterials Collection, featuring papers published over the past few years in PLOS ONE. This collection showcases the breadth of the nanomaterials community at PLOS ONE, and includes papers on a variety of topics, such as the fabrication of nanomaterials, nanomaterial-cell interactions, the role of nanomaterials in drug delivery, and nanomaterials in the environment.
To celebrate this updated collection, we are conducting a series of Q&As with authors whose work is included in the collection. Next out is our conversations with Lauren Crandon from OnTo Technology and Robert Zucker from the U.S. Environmental Protection Agency. In this Q&A, they discuss the importance of understanding the environmental fate of nanomaterials, new technology development, and their experiences of making new discoveries in the lab. We will be adding more author interviews over the next few weeks, so please do keep checking back.
Lauren Crandon – OnTo Technology
Lauren Crandon is a Research and Development Engineer with OnTo Technology in Bend, OR. She develops technology to recycle lithium-ion batteries, including nanomaterials. She received her Ph.D. from Oregon State University in Environmental Engineering, where she researched the environmental fate and impacts of nanomaterials.
Lauren Crandon’s paper in the Nanomaterials Collection: Crandon LE, Boenisch KM, Harper BJ, Harper SL (2020) Adaptive methodology to determine hydrophobicity of nanomaterials in situ. PLoS ONE 15(6): e0233844. https://doi.org/10.1371/journal.pone.0233844
What motivated you to work in this field?
LC: I knew I wanted to study the environmental implications of emerging contaminants. When I first walked into the Harper Nanotoxicology Lab at Oregon State, I got so excited about nanomaterials. I learned that more and more fields in technology, medicine, and industry were using nanoparticles and that these would all be eventually released into the environment. In our lab, we looked at the implications of this at both the small scale (within individual organism) and the large scale (how far downstream nanoparticles will end up). If we can develop a good understanding of fate, transport, and toxicity, we can responsibly develop nano-enabled technology for the future.
Nanomaterials research has increased in popularity over the past few years as a research topic. Do you envision that the field can continue to grow in this way, and do you see any challenges on the horizon?
LC: I absolutely believe the field of nanomaterials will continue to grow. For example, lithium-ion batteries are starting to use nanomaterials to improve performance and nanoparticle-based sunscreens are becoming more popular due to concerns with their chemical alternatives. I think we will also see exciting breakthroughs in nanomedicine, among other fields. The main challenge will continue to be evaluating human and environmental safety at end-of-life for these applications. It is difficult to establish standards and regulations, since the fate and behavior of nanomaterials depends on their environment. However, this will be important for sustainable use.
Can you tell us about an experience during your research, whether in lab or at the computer or in conversation etc., where something finally clicked, or worked?
LC: Yes! I was collaborating with a toxicology graduate student in my lab to compare the toxicity of Cu and CuO nanoparticles in zebrafish. The CuO NPs were much less toxic, but we could not explain why. They dissolved more Cu+2, which was generally accepted to be the toxic mechanism. When I applied one of the standard assays I was working on to measure reactive oxygen species (ROS), the trends matched! Cu NPs generated much more ROS than CuO, which explained the higher toxicity. Applying a standardized test to NPs in a specific testing environment allowed us to model and predict toxicity. I spent the rest of my graduate work continuing to standardize rapid assays for commercially used nanoparticles and correlating my results with their toxicity. I hope this can help us predict the potential risks of materials as they enter the market.
Is there a specific research area where a collaboration with the nanomaterials community could be particularly interesting for interdisciplinary research?
LC: I am very excited about applications of nanomaterials in energy storage devices and medicine. I hope that as these materials continue to enter the market, nanotoxicology research will continue to be funded and part of the story. Nanomaterials offer novel properties that bring major benefits but also do not always follow conventional toxicology. I would like to see collaboration with the technology industry and environmental toxicology to responsibly produce the next generation of novel materials.
Robert Zucker – U.S. Environmental Protection Agency
Dr. Robert Zucker is a Research Biologist at the U.S. Environmental Protection Agency’s Center for Public Health and Environmental Assessment. His research involves applying biophysical technologies of imaging and flow cytometry to reproductive toxicology questions.
Robert Zucker’s paper in the Nanomaterials Collection: Zucker RM, Ortenzio J, Degn LL, Boyes WK (2020) Detection of large extracellular silver nanoparticle rings observed during mitosis using darkfield microscopy. PLoS ONE 15(12): e0240268. https://doi.org/10.1371/journal.pone.0240268
What route did you take to where you currently are in your career?
RZ: I obtained a BS in physics from The University of California, Los Angeles (UCLA) and obtained a master’s degree at UCLA in the Laboratory of Nuclear Medicine and Radiation Biology in the field of biophysics and nuclear medicine. I also received my PhD in biophysics at UCLA studying biophysical separation and characterization of hematological cells. After graduating from UCLA, I did a two-year Post-Doc at the Max Planck Institute in Munich Germany in immunology. When I returned to America, I became a principal investigator at the Papanicolaou Cancer Institute and an adjunct associate professor at the University of Miami for 12 years. In this position, I was involved in cancer research and was a member of the Miami sickle cell center. My next position was at the EPA in Research Triangle Park, NC, applying biophysical technologies of imaging and flow cytometry to reproductive toxicology questions.
What emerging topics in your field are you particularly excited about?
RZ: Flow cytometry has been around for over 50 years. Recently, the technology has been improved by using five lasers with 64 detectors. This provides a system with better resolution. In addition, the software incorporated into the system allows the removal of autofluoresence noise to increase the detection of cells or particles.
Optical microscopes, cameras and equipment have improved to allow scientists to easily obtain digital images, which are high resolution. The new microscopes are automated allowing the scientist to design and achieve experiments that were not previously feasible. For example, the current microscope allows us to use widefield confocal microscopy on 2D images that can be deconvolved with software built into the system for higher resolution. It is quicker than point-scanning confocal microscopy. The machines can obtain sequential measurements over time on one field or take images from multiple fields.
How important are open science practices in your field? Do you have any success stories from your own research of sharing or reusing code, data, protocols, open hardware, interacting with preprints, or something else?
RZ: It is important to follow one’s scientific instincts—the EPA is an organization that allows this freedom to their investigators to research projects of interest to the Agency. I have two success stories to share from my own research.
Success story #1: In the field of nanoparticles, I observed that TiO2 was extremely reflective using darkfield microscopy. Using flow cytometry, granulocytes, monocytes, and neutrophils can be identified based on size (forward scatter) and internal structure (side scatter) from the granules contained in the neutrophils. Can this scatter signal be used to detect a dose response of uptake of nanoparticles by a cell? To try to answer this question, we used two concentration of TiO2 in an experiment, and a dose response was observed with these two-concentration compared to controls. This procedure has subsequently been reproduced by a number of investigations with various types of metal nanoparticles. One of our papers was published in PLOS One and compared the effect of different coating of silver particles coatings on uptake and toxicity by mammalian cells.
Success story #2: The confocal microscope allows scientists to see embryo and reproductive structures in 3D using fluorescence staining technology. By applying very old technologies used to clear tissues, we were able to see very deep into tissues. This procedure allowed the internal structures of reproductive tissues and developing embryos to be observed. The data were used to support the hypothesis that studied how the chemicals affected these tissues.
If you could dream really big, is there a particular material, function or material property that seems far away at the moment, but you think could be attained in the future?
RZ: My dream would be to use the current spectral flow cytometer to predict 1) the effects of microplastics on mammalian cells 2) to detect the effects of climate change on cyanobacteria growth and toxin production 3) to spectrally detect microplastics in water. I would want to provide a simple imaging test to 4) detect microplastics in water by their higher reflectivity 5) to provide an instant imaging quantitation of the amount of Algae and Cyanobacteria in a water sample based on differential excitation fluorescence, and 6) use spectral features of photosynthesis fluorescence and autofluoresence to determine the health of plants and cyanobacteria and then relate this data to the environment.
Disclaimer: Views expressed by contributors are solely those of individual contributors, and not necessarily those of PLOS.
Featured image: http://dx.doi.org/10.1371/journal.pone.0133088