Date of Award
Doctor of Philosophy in Chemistry
Organic synthesis is a powerful tool that is used to solve real world problems from drug development to polymer synthesis. The basis of this work is the development and use of organic chemistry techniques to study pollinator health via the synthesis of small molecule pesticides and detection of microfibers
Pyrethroids are a class of synthetic pesticides with a wide range of agricultural, medical, and veterinary applications. These pesticides are particularly appealing due to the highly tunable molecular structure leading to selectivity towards pests and consistently low mammalian toxicity. The varroa mite, varroa destructor, is an ectoparasitic mite that infests honey bee colonies and transmits deadly viruses and bacteria. Traditional varroa mite management includes the use of an assortment of chemical treatments such as essential oils, natural organic acids, and small molecule pesticides. Three pesticides have been the workhorse for varroa management, however confirmed resistance to two of the compounds has led to widespread decline in honey bee colony health.
The initial focus of this dissertation is to understand the relationships and evolution of pyrethroid insecticides, which includes relevant bioassay data and structure activity relationship analysis for compounds relevant to the lineage of tau-fluvalinate. The second chapter explores the synthesis and subsequent bioassays studies for five fluvalinate derivatives on three species: honey bees, varroa mites, and deer ticks.
Tangentially, this dissertation continues to explore threats to pollinator and global health via terrestrial microplastic mapping. Honey bees are designed to swab their environments and using microscopic hairs on their hind legs, gather pollen and other small fibers. The goal is to analyze pollen pellets collected by honey bees and quantify the microplastic accumulation at various apiaries in Rhode Island. Making trends relating to geographical location and population density, we hope to develop a novel way to sample terrestrial microplastic accumulation.
Lastly, chapter four explores the synthesis of a novel copolyester for biomedical applications. The aims of this work included the synthesis of a biodegradable copolyester and the development of a subcutaneous drug- delivery device. The results of this study demonstrate the use of two different catalyst systems for the small- and large-scale synthesis of these novel copolymers. In addition, drug releasing profiles demonstrate that this novel system performs similar to the non-biodegradable industry standard.
Picard, Kassie, "PESTICIDES, POLYMERS, AND POLLUTION: USE OF ORGANIC CHEMISTRY TO COMBAT THREATS TO POLLINATOR HEALTH" (2023). Open Access Dissertations. Paper 1530.
Available for download on Thursday, May 08, 2025