Research Portfolio

Our research investigates the fate, transformation, and effects of chemicals and particles, focusing on key issues for safe environmental formulations.

We use tools like material characterization, exposure kinetics, hazard assessment, and molecular analyses.

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Current Research Projects

Current Research Projects

Toxicity of chemicals used in vaping

Vaping is widespread, but the potential toxic effects of various ingredients commonly used in vape liquids are not well understood.

This project involves chemical and toxicological studies of nicotine and its analogs, terpenes (used as flavoring agents), and diluents (used to assist the aerosolization of the flavors and active ingredients), and potential synergistic effects between multiple components.

Investigator(s): Taylor Jefferis, Kiera Griffin, Dominic Pruss

Machine learning & statistical predictions

Dose-response curves describe how a drug or chemical's effect varies with increasing dosage. In toxicology, they illustrate the relationship between a toxicological endpoint and dose. Statistical modeling predicts outcomes from limited data, enabling quick, less labor-intensive conclusions.

The relationship can be modeled parametrically or nonparametrically. Parametric models describe a sigmoidal curve with two asymptotes, one at the highest and one at the lowest dose. Nonparametric models avoid shape assumptions. Dose-response models interpolate effects of untested doses, demonstrating the power of statistical modeling.

Investigator(s): Taylor Jefferis, Kiera Griffin, Dominic Pruss

Novel antimicrobial agents

Nanoparticles are proposed as alternatives to traditional antimicrobial agents. By manipulating a particle’s core and surface, antimicrobial effects against microbial populations can be customized. This is referred to as the “designer effect”.

The antimicrobial properties of nanoparticle core–coating combinations are understudied; this research is focused on deciphering their effects on diverse bacteria.

Investigator(s): Brittany Carnathan, Dr. Amanda Sevcik

Fate and transformation of micro- & nanoplastics

Micro- and nanoplastics are an emerging class of environmental contaminants that are widespread. But little is known about their physical, chemical, and toxicological properties. Understanding their behaviour is essential for assessing the risks they pose to ecosystems and human health.

Our research focuses on investigating the interfacial interactions between microplastics and various organic and inorganic substances (such as food, chemicals, and other particle types) in aqueous environments. We examine the leaching of plastic additives and study the degradation mechanisms under simulated environmental conditions.

The biological effects of the plastics and their degradants are also a focus of this work.

Investigator(s): Taiwo Ayorinde, Johnny Werst, Merideth Harvey

  • Ayorinde T, Penrose MT, Cobb GP, Sayes CM.

    Water, Air, & Soil Pollution. 2025 Sep;236(9):567.

  • Ayorinde T, Sayes CM, Al Naggar Y.

    Journal of Insect Physiology. 2024 Oct 1;158:104697.

  • Al Naggar Y, Sayes CM, Collom C, Ayorinde T, Qi S, El-Seedi HR, Paxton RJ, Wang K.

    Toxics. 2023 Jan 21;11(2):100.

  • Al Naggar Y, Brinkmann M, Sayes CM, Al-Kahtani SN, Dar SA, El-Seedi HR, Grünewald B, Giesy JP.

    Toxics. 2021 May 15;9(5):109.

Therapeutics for plant disease

Huanglongbing (HLB) is the most devastating disease in the citrus tree, and is caused by Candidatus Liberibacter asiaticus (bacterial pathogen) and transmitted by Diaphorina citri (psyllid, vector).

This project aims to develop novel antimicrobial encapsulated nanoparticles that enter the plant vascular system (phloem), resist degradation, and accumulate in the roots where bacteria reside.

Investigator(s): Dinny Stevens, Dr. Amanda Sevcik