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Do Particle Properties Modulate bioaccumulation, Trophic Transfer and biomagnifications of engineered nanomaterials: Role of Particles size, shape and surface coating? - BTBnano

Periodic Reporting for period 1 - BTBnano (Do Particle Properties Modulate bioaccumulation, Trophic Transfer and biomagnifications of engineered nanomaterials: Role of Particles size, shape and surface coating? - BTBnano)

Reporting period: 2018-03-01 to 2020-02-29

The past decade has seen the emergence of a new class of manufactured materials known as engineered nanomaterials (ENMs); generally defined as materials having at least one dimension at the nanoscale (1-100 nm). They are produced in vast amounts all over the world and designed with different properties e.g. sizes, shapes, and compositions, to be used in consumer products and for different industrial or medical applications. Increasing global production volumes of ENMs inevitably result in their release into aquatic ecosystems. This raised some safety issues regarding the possible toxicity of these materials for biota and for humans. The first decade of research leads to the conclusion that the expected levels of environmental release of ENMs are not likely to cause acute toxicity. Some metal-based (MB)-ENMs, e.g. gold(Au) ENMs, and carbon-based ENMs, e.g. carbon nanotubes (CNTs), are persistent materials in the environment and in biota. Other MB-ENMs in water will, subsequently, fully or partly dissolve to their constituent ions. Recently it has been reported that dissolvable MB-ENMs do not require nano-specific hazard assessment, and instead, read-across of the properties of the dissolved materials to the corresponding bulk materials may be used. On the other hand, concern has been raised about bioaccumulation and biomagnification of CNTs and persistent MB-ENMs in organisms and subsequent chronic toxicity. Consequently, novel research questions pop up, such as: Do CNTs and persistent MB-ENMs bioaccumulate in organisms? Are they transferred through food chains and induce biomagnification in predators to subsequently cause chronic effects? Which physicochemical properties of ENMs modify these processes? There are currently gaps of knowledge in understanding the underlying processes and lack of concepts to model these processes for ENM risk assessment. Herein, my ambition is to provide novel approaches to some of the major knowledge gaps
that the nanosafety community will need to address for ENM-tailored risk assessment.
Objective 1: Systematic quantification of bioaccumulation and biodistribution of SWCNTs (as a function of size) and Au ENMs (as a function of size, shape and surface coating) in D. magna and D. rerio at chronic exposure conditions. I will demonstrate whether ENMs that are composed of the same core but differ with regard to the mentioned properties, also differ with regard to their bioaccumulation and biodistribution.
Objective 2: Study the influence of particle size, shape and surface coating of Au ENMs and size of SWCNTs on their trophic transfer along an assembled aquatic food chain consisting of a primary producer (C. pyrenoidosa) and a primary (D. magna) and a secondary consumer (D. rerio). I will demonstrate whether SWCNTs and Au ENMs can be transferred to higher trophic levels, how the properties of the particles influence the bioavailability of SWCNTs and Au ENMs in D. magna to D. rerio and how the properties of the particles influence the biodistribution of the ENMs in D. rerio.
Objective 3: Study the potential for biomagnification of SWCNTs and Au ENMs in an assembled aquatic food chain when mass and particle number concentration are considered as dose metrics. The algae and Daphnia will be exposed to a mixture of three different sizes of SWCNTs or a mixture of three different sizes of Au ENMs. I will (a) demonstrate whether particles number concentration is a suitable dose metric to investigate the biomagnification of ENMs and (b) develop a model for predicting biomagnification of ENMs based on the proper dose metric.
Exposure of C. pyrenoidosa and D. magna to Au ENMs dispersions and monitoring the aggregation behavior of the particle in the exposure media. Quantification of uptake, internalisation and biodistribution of Au ENMs (as a function of size, shape and surface coating) in the gut and total body of D. magna.
Report on the influence of size, shape and surface coating on the bioaccumulation, internalization and biodistribution of the ENMs in D, magna
Report on the application of sp-ICP-MS for MB-ENM quantification in biological media
Report on the application of TEM and AF4 for quantification of SWCNTs in biological media

Determination the behaviour of SWCNTs in the environment and the trophic transfer of Au ENMs in particulate form from D. magna to D. rerio. Herein, the D. rerio was fed with the ENM-exposed D. magna and the bioaccumulation of the ENMs in D. rerio was quantified. Investigating the influences of particle properties on the bioavailability of Au ENMs from D. magna to D. rerio.

Report on the trophic transfer of the ENMs in aquatic food webs and the bioavailability of the ENM in prey to predator.

Exposure of D. magna to a media containing a mixture of 3 different sizes of stable SWCNTs or Au ENMs. Feeding D. rerio with the exposed D. magna and quantification of the mass and number concentration of the bioaccumulated ENMs in the D. rerio.
The current state of the art:
Investigation of carbon-based ENMs in biological media using digestion methods and/or using electron microscopy. It is challenging to distinguish carbon-based ENMs from the background of organic compounds.
Beyond state of the art:
Quantification of carbon-based ENMs in biological matrices
Innovation:
Developing an approach using AF4 for quantification of carbon-based ENMs in biological matrices

The current state of the art:
Investigating bioaccumulation, biodistribution, and trophic transfer of ENMs in a scattered way and based on mass. Herein, it is not possible to understand how the properties of ENMs influence the particles bioaccumulation, biodistribution, and transfer and provide information about particles within tissue/cell
Beyond the state of the art:
Systematic quantification of bioaccumulation, biodistribution and trophic transfer of ENMs as a function of size, shape and surface coating. Understanding the influence of particle properties on their bioaccumulation, biodistribution and trophic transfer. Gaining information about bioaccumulation, biodistribution and biomagnification of the particulate form of MB-ENMs within the biological media
Innovation:
Developing methods for mapping and quantification of MB-ENMs in cells and in tissues using sp-ICP-MS

The current state of the art:
Investigating biomagnification of ENMs following traditional methods for non-particulate contaminants
Beyond the state of the art:
Replacement of mass as dose metric with other properties for investigating biomagnification of ENMs
Innovation:
Evaluating particle number concentration as a dose metric to replace mass concentration in studies dealing with biomagnification of ENMs and develop a model for biomagnification of ENMs