Leveraging Swelling Polymer Nanoparticle Reversibility for Cargo Loading
To achieve the United Nations’ goal of eradicating hunger by 2030, it is necessary to improve crop production through sustainable and cost-effective solutions. Nanoparticles are increasingly being used to improve agricultural crop production because they can promote nutrient absorption, lower soil and water contamination, and increase the plant’s resilience in non-ideal environments. Polymeric nanoparticles like poly-2-(diethylamino)ethyl methacrylate (pDEAEMA) have extensively been used for drug delivery in biomedicine due to its ability to reversibly swell in acidic media, a property this work optimized to serve as a cargo loading mechanism for agricultural applications. Rhodamine B isothiocyanate (RITC) was used as a model cargo to load. pDEAEMA of three different sizes were synthesized using a free radical polymerization with varying synthesis temperature. Their pH-dependent size, surface charge, and swelling behavior were extensively characterized using dynamic light scattering and transmission electron microscopy, while the dye loading and release was optimized using fluorescence measurements and confocal microscopy, in comparison with a non-swelling polymer control. pDEAEMA nanoparticles showed significant fluorescence following dye loading in comparison to the non-swelling control, suggesting that the reversible swelling is necessary for successful loading. Following acid treatment, the fluorescence intensity decreased, potentially due to the dilution of the dye when released. Results suggest a swelling reversibility-driven cargo loading mechanism with the potential to be applied to other beneficial cargo and applications. Future work will focus on the load and release of beneficial cargo for agricultural applications and explorations of pDEAEMA-leaf interactions.