Degree

Doctor of Philosophy (PhD)

Department

Biological Engineering

Document Type

Dissertation

Abstract

This research examined the effect of biodegradable, polymeric, lignin-based nanoparticles (LNPs, 113.8±3.4, negatively charged) and zein nanoparticles (ZNP, 141.6±3.9, positively charged) on soybean plant health. The LNPs were synthesized from lignin, covalently linked to poly(lactic-co-glycolic) acid by emulsion evaporation. ZNPs were synthesized by nanoprecipitation. Soybeans grown hydroponically were treated with three concentrations (0.02, 0.2, and 2 mg/ml) of NPs at 28 days after germination. The effect of ZNPs and LNPs on plant health was determined through analysis of root and stem length, chlorophyll concentration, dry biomass of roots and stem, as well as carbon, nitrogen, and micronutrient absorption after 1, 3, 7 and 14 days of particle exposure. Biomass and plant length were not affected by polymeric NPs treatments at doses less than 0.2 mg/ml, and cationic ZNPs had a more significant impact than LNPs at high concentrations of 2 mg/ml affecting nutrient uptake in some cases. Next, two types of lignin, alkaline lignin (ALN) and lignosulfonate (SLN) were grafted with PLGA at different ratios (1:2 or 1:4 w/w) and the effect of the type of lignin and LGN:PLGA ratio on the release profile of methoxyphenozide (MFZ) was compared at pH 4, 7 and 11 at two temperatures, 25 and 37°C. Faster release occurred at higher temperature both ALN and SLN particles while SLN particles were more sensitive to pH than ALN particles providing the desired pH responsive effect. Polymeric nanoparticles have the ability to reduce the environmental impact of pesticides due to their biodegradable, tunable and controlled delivery characteristics.

Committee Chair

sabliov, cristina

Available for download on Thursday, January 20, 2022

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