Environmental Science
Christopher Rodriguez, Christopher_Rodrigu1@baylor.edu
Baylor University, with Dr. Christie Sayes and Dr. Mohamed Salah
Optimization Of Copper Nanoparticle Synthesis For Antimicrobial Applications
Copper nanoparticles (CuNPs) are studied as novel antimicrobial agents due to their bactericidal properties. The small size, high surface area, and ability to disrupt and damage bacterial membranes make them excellent candidates for improved efficiency and mitigated resistance. This study investigates the optimization of CuNPs synthesis using experimental nanocrystalline growth conditions, such as pH, the order of adding reactants to the mixture (i.e., copper sulfate (CuSO4), trisodium citrate (TSC), and sodium borohydride (NaBH4)), reagent concentrations (i.e., 3mM CuSO4, 12mM NaBH4, and 3mM TSC), atmospheric conditions (i.e., nitrogen purge), and temperature of the reaction (i.e., room temp). The pH of the synthesis scheme has not been extensively studied in the literature; therefore, this study aims to determine the optimal pH for producing CuNPs. The results revealed that adjusting the pH of the reaction solution to 10 yields the best nanoparticle product in terms of stability in water, monodispersity, negative surface charge, and ultraviolet-visible light absorbance, indicating the formation of copper particles. This work continues to lay the foundation for optimizing nanoparticles for use as next-generation antimicrobial agents.
Jaden Walker, jadenwal@ttu.edu
Texas Tech University , with Dr. Jordan Crago
Chronic Polydispersed Nanoplastic Exposure in Daphnia magna: Assessing Transgenerational Transfer to Neonates
Nanoplastics (NPs, <1 µm) pose significant ecological risks to aquatic organisms, such as the water flea Daphnia magna, due to their small size, which allows for ingestion and potential translocation across gut epithelial cells. While toxic effects are well-documented in adult Daphnia, limited research has investigated their transgenerational impacts. Additionally, most studies use monodispersed, spherical, commercially available particles, overlooking the environmental relevance of irregular, polydispersed NPs, creating uncertainty between laboratory and the environment. To resolve this uncertainty, we synthesized environmentally relevant, polydispersed polymethyl methacrylate nanoplastics doped with tantalum (Ta-PMMA), allowing for single-particle inductively coupled plasma mass spectrometry (spICP-MS) quantification. This enabled precise quantification and characterization of particle size distribution in Daphnia and media. Daphnia magna were chronically exposed to 500 ng/L of Ta- PMMA NPs for 21 days, with adults sampled on days 7, 14, and 21, and neonates collected daily. Spawned neonates were counted for clutch size, and a subset was raised in clean or NP exposed water to assess particle retention. Ta-PMMA particles (265 1000 nm) were detected in both adults and neonates, with no significant change in particle numbers across adult time points. However, exposed adults produced significantly fewer neonates than controls. This study demonstrates transgenerational transfer of environmentally relevant nanoplastics and identifies associated reproductive effects. Our design enabled detection of transferred particle sizes and highlights the need for representative NP models in ecotoxicology to better understand the implications of chronic, realistic exposures on aquatic invertebrates and their offspring.
Thomas Morley, thomas_morley1@baylor.edu
Baylor University, with Dr. Christie Sayes & Dr. Amanda Sevcik
Developing a Stable Nanoparticle Delivery System for the Treatment of Citrus Greening Disease
Nanoparticles are utilized in agricultural applications as pesticides and fertilizers to mitigate plant stress and to improve soil quality. The properties of nanoparticles make them promising for suppressing pathogens and improving micronutrient delivery. This research focuses on the use of antimicrobial agents to eliminate Huanglongbing (HLB) bacterial infections in citrus plants, commonly known as Citrus Greening Disease. As of 2024, approximately $1 billion was lost annually in the U.S. due to the disease. The terminal infection, characterized by blotchy leaves, yellow veins, and small, discolored fruit, reduces crop quality and yield. However, the treatments used to date have not been easily absorbed across the leaf’s cuticle (after foliar spray) or into the root (after soil amendment). To increase the absorption of therapies, nanoliposomes have been synthesized and loaded with antimicrobial agents. These constructs have been shown to cross the plant’s barrier membranes, allowing them to translocate into internal tissue. My objective is to assess the efficacy of loaded nanoliposome constructs post-processing via freeze-drying and reconstitution. Critical quality attributes (CQAs) will be used to quantify the physical and chemical properties of the suspended and reconstituted forms. This research will examine the strengths and limitations of liposome lyophilization for the stability and efficacy of delivering antimicrobial drugs to infected plants. In addition, my work will continue to lay the foundation for nanoliposome encapsulation, drug delivery, and enhanced absorption, building upon current therapeutic intervention strategies for field work.