Nano-scale Plastic Aquatic Toxicology
Aquatic ecosystems are polluted with plastic waste on a global scale. As plastics degrade in the environment, they inevitably pass through the size range in which they would be considered microplastics (< 5mm) and nanoplastics (1-1000 nm). The goal of this research is to provide foundational information about what physicochemical properties (e.g., composition, size, shape) and environmental components (e.g. salinity, pH, organic matter) are determinative of risk. This project entails 1) a thorough characterization of the physicochemical composition, size, and shape of common plastics that have been milled to the micro- and nano-scale, 2) studies to determine the biological consequences of micro- and nanoplastics exposure in freshwater and estuarine model organisms using rapid toxicity testing strategies, and 3) studies to determine how real world transformations of micro- and nanoplastics may alter plastics fate or the fate of plastic additives and co-contaminants. All of the data from these studies will be used to inform a multi-stressor risk assessment model.
Zebrafish EZ Metric Assay
Since virtually every element on the periodic table is fair game for exploration in nanotechnology, the sheer diversity of nanomaterials makes it impractical to utilize our current testing paradigms to evaluate every new nanomaterial. We use the embryonic zebrafish as an in vivo model to easily and rapidly advance our understanding of the biological consequences of nanomaterial exposure. This model system offers the power of whole-animal investigations (e.g. intact organism, functional homeostatic feedback mechanisms and intercellular signaling) in a convenient cost- and time-efficient manner.
Nano-Crystalline Cellulose (NCC)
The overall objective of the NCC project is to determine the relative influence that size, shape and surface chemistry of nanoparticles has on their uptake and biological effects as well as to understand the mechanism of toxicity. NCC is an innovative platform for testing data-derived nanoparticle structure-activity relationships (nanoSARs). NCC is thought to be predominantly non-toxic, thus key features that confer toxicity to some nanomaterials can be elucidated though deliberate permutations of the physical structure of NCC. With over 100 years of cellulosic chemistry to rely on, engineers in wood science engineering here at OSU have partnered with our lab to establish new methods of NCC synthesis and characterization to formally test the validity and limitations of data-derived nanoSARs.
Nanocosm Assay
Rapid testing strategies are necessary to identify the specific features of nanomaterial that result in toxicity in order to mitigate risks from exposure and define structure-property relationships that can be used to predict nanomaterial fate and hazard in lieu of empirical data. Mesocosms and microcosms are now widely accepted as useful tools for investigating the ecotoxicity of a substance since they take into account relevant aspects from a simulated ecosystem such as bioavailability, indirect effects, biological compensation and recovery, as well as community level effects and the potential for trophic transfer and biomagnification. Traditional micro/mesocosm studies are time-intensive and require a large amount of material for testing. Our goal is to overcome these critical limitations in ‘nanocosms’ which are small-scale simulated ecosystems with reliable reference conditions and sufficient cost-effective replicates.
Oxidative Potential Assay
This project aims to develop a rapid and cost effective testing strategy to examine nanoparticles for their oxidative potential. Reactive Oxygen Species (ROS) are often the root of chemical reaction cascades that lead to free radicals and oxidative stress. Some nano-scale particles show strong chemical reactivity and can act as reaction catalysts. In biological systems, these same properties can also lead to a destructive process called oxidative stress. Oxidative stress is biological damage caused by highly reactive molecules like free radicals. Oxidative stress plays a part in many diseases such as: atherosclerosis, Alzheimer’s disease, cancer, Parkinson’s disease, stroke, and even aging. The information from this assay will further be used to interpret the physiochemical properties of nanomaterials that are responsible for causing oxidative stress in biological systems.
Hyperspectral Imaging
Our lab uses a Cytoviva Hyperspectral Imaging System to detect nanomaterials and agglomerates in biological samples. The system creates an image of the sample containing spectral information through the visible range, which is then compared to the reference spectra of a known sample in order to determine if nanoparticles are present in the target sample. The HIS system can be used to qualitatively assess the distribution of nanomaterials in complex biological matrixes such as animal tissues or algae.
Nanomaterial-Biological Interactions Knowledgebase
The Nanomaterial-Biological Interactions knowledgebase (NBI) is a collaborative web-based database designed to integrate relevant data from ongoing academic, government, and industrial research on nanotechnology. The NBI serves as an open-source repository for data on nanomaterial characteristics and their biological interactions. Users can access unbiased information from the database to help identify the relative importance of characterization parameters on nanomaterial-biological interactions.To access the database go to nbi.oregonstate.edu.
Effects of Pesticide Nanotechnology on Vulnerable Organisms
Nanotechnology-based pesticides (NBPs) are based on existing active ingredients, and possess internal functional features less than 100 nm that are purposely engineered to have different properties in the environment than the active ingredient. Nanoformulation of pesticides may not increase the toxicity of the active ingredient per se, but are likely to alter their environmental fate. The overarching goal of the project is to reduce the uncertainty associated with NBP formulations in terrestrial and aquatic environments and communities through simultaneous studies of NBP toxicity in honey bees, zebrafish and other aquatic organisms.