Biodistribution and transpiration of nanoparticles in celery (apium graveolens var. secalinum)

Abstract

Nanomaterials have unique and enhanced physical and chemical properties, which make them interesting in industrial and biomedical applications. However, there is no complete knowledge of the possible effects they might have on the human body or the environment. Study was conducted on biodistribution and transpiration of nanomaterials in Chinese celery (Apium graveolens var. secalinum) because if nanomaterials can accumulate into the edible parts of the plant, it means that humans may consume them; if nanomaterials can undergo transpiration, plants aid in the dispersion of nanomaterials into the air making humans more prone to inhale them. To the best of the author's knowledge, this research is the first to investigate if nanoparticles will undergo transpiration. Celery was chosen as the plant model because it is short, less drought-tolerant, and has a high leaf surface area to maximize transpiration. It was demonstrated that filled silica and hollow silica can undergo transpiration which may serve as a representation that different nanomaterials encapsulated with silica can be transported from the roots to the stem, leaves and out of the plant. Iron oxide nanoparticles coated with inert silica were proven to eventually be released from the plant by transpiration, with a rate of 273±164 µg/m²day, which is comparable to the transpiration rate of total silica. Iron oxide, silver nanoparticles, UiO-66-NH₂ MOF, and carbon dots can be biodistributed, but cannot undergo transpiration efficiently; however, silica can drive that. Celery can utilize biogenic silica and a certain reaction that appears to be converting the UiO-66-NH₂ MOF with some silica was observed. Even though the nanomaterials appear to biodistributed and in our study is not detectable in the transpiration droplets, there is a potential that the plant during its process may transform and convert nanoparticles with biogenic silica which will then facilitate its eventual release to the environment.

Date of Award	2022
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	King Lun YEUNG (Supervisor)