Plastic pollution is an ever-increasing environmental threat. As large-scale plastics break down to form nanoscale plastics, it is essential to investigate their effects on freshwater ecosystems. With many plastic nanoparticle (NP) studies favoring the effects of common polystyrene (PS) plastics, a gap is formed for other common plastic types like...
Plastics have become an essential part of everyone lives, found in almost every product made today. Tires only make up a fraction of these products but as their use increasing so does the microplastics that flake off. Many studies have evaluated the toxic effects of tire particles on aquatic environments...
My work in the Harper Nanotoxicology Lab focuses on science communication. The Harper Lab conducts research to address data gaps regarding the toxicity of micro and nanoplastic in the environment, specifically in aquatic habitats. It is important for the public to understand what the lab does, and how they can...
Hydrophobic titanium dioxide (TiO2) nanoparticles (NPs) are prevalent in industry and manufacturing. They are known for their white pigmentation, are found in sunscreens, paints, cosmetics, and are frequently used in wastewater treatment. Understanding the physicochemical properties of TiO2 P-25 NPs, such as hydrophobicity, are essential when determining their fate, transport,...
Nanoparticles (NPs), particles defined by their size in a single dimension (1-100 nm), are being increasingly incorporated into commercial and industrial products due to their high surface area to volume ratio that gives them unique properties, such as optical tunability and higher reactivity than their bulk counterparts. NPs can be...
As nanoparticle (NP) research and development expands, the significance of NP biodistribution effects on toxicity increases. A reliable method for measuring NP biodistribution is critical. Hyperspectral Imaging (HSI) is capable of accurately quantitating NP biodistribution within embryonic zebrafish with incredibly high precision. Before HSI processing, the embryo must be sectioned...
Antimicrobial agents are being increasingly used in consumer soaps and detergents, despite a lack of data demonstrating their efficacy in such products. This study investigated the nature of the interaction between different crystalline structures of titanium dioxide nanoparticles and BTC, and explore which structure, if any, could be best used...
Dendrimers are well-defined, polymeric nanomaterials currently being investigated for their biomedical applications. Initially, higher generation (size) dendrimers were of interest because of their drug carrying capacity. However, increased generation was associated with increased toxicity. The objective of the present study was to investigate the role of surface charge and generation...
Emerging data showing the presence of atmospheric microplastics (MPs) has recently raised awareness surrounding the potential of human nanoplastics (NPs) exposure. Due to factors such as weathering, UV exposure, and other biodegradation processes, plastic pollution in the environment breaks down over time into micro (<5 micrometers) and nanoscale (<1000nm) particles....
Nanoscale polymers (including nanoplastics) are widely present through commerce and make their way into the environment. As the improper disposal of plastic waste leads to continued accumulation and degradation of plastic pollution, the presence of plastic particles less than 1 micron (μm) in size (nanoplastics) will increase. Heightened concern over...
Nanotechnologies continue to permeate a multitude of industries, with diverse applications ranging from pesticides to fuel additives. The unusual behavior of nanomaterials that drives their innovation also complicates the job of toxicologists tasked with assessing their potential environmental and public health impacts. This dissertation investigates the underlying reasons for uncertainty...
Nanoparticles (NPs), defined by their size (1-100 nm), are increasingly incorporated into commercial and industrial products due to their high surface area and unique properties. They can be designed for specific applications by manipulating composition, size, shape, and surface functionalization. As NP production and complexity increases, there is a need...
The ability of nanoparticles (NPs) to induce oxidative stress on organisms has been linked to NP cytotoxicity and genotoxicity for a variety of organisms. One proposed mechanism of this increased oxidative stress is the ability of NPs to generate reactive oxygen species (ROS). Due to the dynamic nature and small...
Nanoparticles (NPs) are generally defined as particles <100 nanometers (nm) in size in one dimension. Despite increasing industrial usage of TiO2 NPs in sunscreens, cosmetics, and water remediation little is known of their environmental behavior. The primary goal of this research was to develop a rapid method for determining the...
Numerous studies have shown that some nanomaterials are highly toxic to aquatic organisms and can potentially disrupt overall community health; however, current methods to evaluate the nanomaterials environmental impacts rarely consider the environmental realism or provide sufficient detail on the impact at the community level. Here we demonstrate three approaches...
Within the past two decades, the rise of nanotechnology has provided various technological and industrial sectors with avenues for significant growth and improvements to existing practices. With the inherent qualities which make materials on the nanoscale unique in behavior and function, there are limitless applications of nanotechnology. One of the...
Zero valent iron nanoparticles effectively remediate groundwater contaminants due to their catalytic properties and enhanced surface area. However, these properties contribute to particle agglomeration, decreasing their effectiveness. In this study, we examined the effect of two stabilizing agents (gum arabic (GA) and sodium carboxymethyl cellulose (CMC)) on particle stability, toxicity,...
The low risk and sustainable implementation of nanotechnology requires understanding how nanomaterial physicochemical properties influence their toxicity. Major drivers of toxicity need to be avoided while maximizing product efficacy so nanomaterials can be produced to best serve their applications and be of low risk when intentionally or unintentionally released into...
Nanotechnology products have long since made their way to markets around the world increasing the concerns about whether nanomaterials pose a risk to our environment or health. It has been suggested that engineered nanomaterial (ENM) with broad applications and rapid commercialization need better risk assessment and regulation. However, the refinement...
The level of reactive oxygen species (ROS) is tightly regulated in biological systems as overproduction can lead to oxidative stress and result in a number of diseases. Due to its negative effects, antioxidants are studied and used against ROS in medicine, pharmaceuticals and therapeutics. Because of issues with the uptake...
Characterizing the hydrophobicity of nanoparticles can help us understand their fate and transport in the environment, as well as how nanoparticles may interact with biological systems. However, contact angle and partition coefficient have limitations in measuring the hydrophobicity of nanoparticles, thus promising methods to measuring the hydrophobicity of nanoparticles are...
Many studies addressing the toxicity of silver nanomaterials have found that smaller sized silver nanoparticles are usually more toxic to organisms and in cell culture than particles of larger sizes yet it is not entirely clear why. We investigated the size dependent toxicity of silver nanoparticles by measuring the response...