Environmental behavior and toxicity of micro- and nanoplastics
Plastic has become the largest pollutant in the aquatic environment, mainly due to its extensive use and slow degradation in the environment. Microplastics (MPs) are small plastic particles, less than 5 millimeters in size, that are either intentionally manufactured at that size or result from the breakdown of larger plastic debris over time. These particles can enter water bodies through various sources, including direct release from manufacturing processes, improper waste management, and the fragmentation of larger plastic under environmental conditions. Our overreaching research goal is to estimate the environmental impact of microplastic and nanoplastic (NPs) in the aquatic and terrestrial environments focusing on the following sub-projects:
1. Synthesis of size-controlled and environmentally-relevant MPs and NPs, as well as microfibers – using a top-down approach
2. Evaluation of the potential of MP and NP models to adsorb (and desorb) organic and inorganic contaminants present in natural waters
3. Assessment of the toxic effect of MP and NP with and without adsorbed pollutants from the environment using a single cell model (in vitro test)
4. Sustainable removal of MPs from the aquatic environment using aquatic living forms
Plastic pollution is everyone’s problem: (A) Heterogenous size and morphology of microplastics detected at the Israeli coastline and (B) conceptual illustration of sorption of organic contaminant onto microplastics and their potential joint toxicity
Environmental implications of using nanomaterials
Nanomaterials are extensively used in a wide range of industrial applications owing to their exceptional physical, mechanical, and electrical properties compared to their corresponding bulk materials. However, these unique properties, which make nanomaterials so attractive, also pose potential risks for human health and the environment. Specifically, a growing environmental concern is the contamination of water sources with nanomaterials released through a plethora of discharge routes.
One of the main challenges associated with emerging nanomaterials is monitoring and characterizing their toxicity in water. Current approaches assessing toxicity use discrete sampling methods followed by laboratory analyses with living cells, an expensive and time-consuming process providing no real-time data. In light of inherent complexities and dynamics in cell membranes, artificial membranes are suggested as model systems to gain fundamental insights into nonspecific interactions of cells and may assist to anticipate toxicity of nanomaterials of different structure and surface chemistry.
Environmental implications of nanotechnology throughout their life cycle.
Quantifying the risk: decoupling structure and surface chemistry in nanomaterial toxicity
Recently, we used dye-leakage assays to quantify the disruption of a model phospholipid bilayer membrane by emerging nanomaterials of different chemical composition, orientation, and morphology. Different levels of dye leakage from the vesicle inner solution, indicating a loss of membrane integrity, was observed for a set of two-dimensional nanomaterials while oxidative stress resulted in no loss of membrane integrity. These results suggest that chemical composition plays an important role during physical membrane–nanosheet interactions. We also observed an orientation-dependent interaction using aligned graphene oxide composite films, which was attributed to the density of edges with a preferential orientation for membrane disruption. In our on-going study, we complement these findings and assess the disruption of phospholipid bilayer membranes by manganese oxides of different morphologies.
A rapid nanomaterial toxicity sensor kit based on interactions of various lipid bilayers with nanomaterials
Interactions of various modified lipid vesicles (i.e., model-cell indicators) with engineered nanomaterials can be demonstrated simultaneously in real-time by a dye-leakage assay. We are working on the development of a soft-matter based sensing platform for engineered nanomaterials, which uses interactions of nanomaterials with a set of modified lipid bilayers designed to mimic specific cells of interest. By efficiently pinpointing toxicity in real-time, this kit will lessen release of toxic nanomaterials to the environment and drinking water, as well as inform the design of green, less-toxic nanomaterials.
(A) Schematic illustrating the experimental set-up, lipid vesicle structure encapsulating a fluorescent dye at high concentration, and possible mechanisms of interaction between nanosheets and vesicles.
(B) Kinetics of fluorescent dye leakage from vesicle inner solution to the extravesicular solution induced by two-dimensional nanomaterials.
1. I. Zucker, J.R. Werber, Z.S. Fishman, S.M. Hashmi, U.R. Gabinet, X. Lu, C.O. Osuji, L.D. Pfefferle, M. Elimelech; Loss of phospholipid membrane integrity induced by two-dimensional nanomaterials – pp. 404–409, 2017, Environmental Science & Technology Letters.
2. X. Lu, X. Feng, J.R. Werber, C. Chu, I. Zucker, J. Kim, C. Osuji, M. Elimelech; Enhanced antimicrobial activity through the controlled alignment of graphene nanosheets – pp. E9793–E9801, 2017, Proceedings of the National Academy of Sciences.
3. A. Kumar Sarkar, A. E. Rubin, I. Zucker; Engineered Polystyrene-Based Microplastics of High Environmental Relevance – pp 10491–10501 (55), 2021, Environmental Science and Technology.
4. AE. Rubin, I. Zucker; Interactions of microplastics and organic compounds in aquatic environments: A case study of augmented joint toxicity – pp 133212 (289), 2022, Chemosphere.
5. A.E. Rubin, L. Omeysi, I. Zucker; Mediterranean microplastic contamination: Israel’s coastline contributions – 114080 (183), 2022, Marine Pollution Bulletin.
Development of advanced water-treatment technologies which leverage the reactive and tunable properties of nanomaterials for selectivity toward priority pollutants, cost-efficiency and sustainability