Abstracts

Thursday 29 june 2023

When we downsize the matter to the sub-nanoscale, new fascinating physical and chemical properties may appear. Understanding and controlling the properties of two-dimensional materials has fostered, in the last twenty years, huge and multidisciplinary research efforts in condensed-matter physics and material science.

On the other side, atomic nanoclusters provide a great example of this behavior. The size selection with single atom precision can showcase modifications of the properties even by adding or removing a single atom. These clusters represent an unprecedented playground to look for new properties of matter, with applications appealing to many areas of materials science. A new world unfolded before our eyes, showing us that the properties of bulk matter and solid surfaces cannot be easily extended to nanoclusters.

Engineered Nano Materials (ENMs) have multiple applications due to their size-dependent properties. In this talk, the most common methods of ENMs synthesis and characterisation will be discussed. Regarding the synthesis, both top-down and bottom-up approaches will be described. The top-down methods will include milling and laser ablation; for the bottom-up synthesis, processes such as colloidal (i.e., surfactants), combustion, and hydrothermal synthesis will be described.

Regarding the characterisation, the discussed techniques will include Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), and Atomic Force Microscopy (AFM). Selected examples of synthesis and characterisation will be presented to better understand the systems and their potential applications.

After about 25 years of basic nanoscience research, applications of nanotechnology are delivering on nanotechnology's promise to benefit society. Nanotechnology is revolutionizing many technology and industry sectors: medicine, information technology, transportation, energy, and many others. In the face of a constantly increasing global demand for food, the production processes of conventional agriculture suffer from a particular inefficiency which results in an increasing negative environmental pressure. There are, therefore, strong expectations regarding the so-called nano-enabled agriculture. However, for some reason, compared to other sectors, nanotechnologies' applications in agriculture lag significantly.

The talk reconstructs the birth and development of knowledge on the relationship between cultivated plants and engineered nanomaterials. Both the potential perspectives of nano-enabled agriculture and the knowledge gaps are also considered.

The risk assessment of small particles (including nanoparticles) in products used in the food chain in the EU falls within the remit of the European Food Safety Authority (EFSA) and has been under thorough scientific consideration for over a decade. The lecture will review the principles underlying the safety testing of small particles, referring to two recently published EFSA guidance documents. The starting point is the physicochemical characterisation of the pristine material, being an engineered nanomaterial, a nanostructured material, or a conventional material that contains a fraction of small particles that may retain properties at the nanoscale.

Where there is a likelihood of small particles remaining after gastrointestinal digestion, hazard identification and hazard characterisation are required with special provisions. In particular, certain nano-specific considerations must be considered during toxicological testing to demonstrate the consumer safety of products used in the food chain in Europe.

Plant Growth Promoting Rhizobacteria (PGPR) are a heterogeneous group of bacteria characterized by their ability to influence crops' growth and fitness. In the quest for more sustainable practices, PGPR have been suggested as an excellent complement to agronomical practice. Indeed, PGPR can directly or indirectly affect plant growth by influencing several biochemical and molecular mechanisms related to the uptake of mineral nutrients, plant pathogens suppression, and the production of phytohormones.

The possible combined application of PGPR along with nanomaterials may thus be a suitable strategy for managing crop growth and yield in sustainable development. However, it must be considered that engineered metal nanoparticles can have both positive and negative impacts on rhizobacteria. Hence, more studies are needed to investigate further engineered nanoparticles' effect on the microbial communities inhabiting plants' rhizosphere.

The intense use of pesticides has progressively contributed to the contamination of the environmental matrices, particularly soils, and groundwater. Nanopesticides (NPs) have been recently proposed to overcome traditional agrochemicals' diverse technical and ecological issues. They consist of nanoparticles (nanocarriers) containing an active ingredient, protected by a coating, and dispersed in a colloidal suspension. To evaluate NP mobility in the subsoil and thus their environmental fate, traditional modeling approaches are only partially applicable due to the colloidal nature of NPs.

To this aim, the key characteristics of NPs are revised here, and a modeling framework for assessing their environmental fate is discussed. An example of a novel nanoformulation is also presented, based on eco-compatible materials (mineral particles and food-grade biopolymers) and applied to dicamba, a highly soluble herbicide, to control its delivery and reduce its environmental spreading.

Technology's benefits to a green and sustainable economy are highly appreciated and under intense research and development globally. Circuits and Systems (CAS), the base for any system, can bring the needed functionalities and performances for reaching eco-friendly, circular, and practical solutions. The IoT in agriculture is exponentially increasing, proving that Precision Agriculture is a very fast-growing research field, where more controlled quality production, water use optimisation, and a lower spreading of pesticides and fertilisers are some key issues, serving the improvement of food quality, but also helping the respect of agriculture for the environment.

In the talk, an overview of electronics for precision agriculture will be presented, analyzing the possible solutions that can bring essential innovations, advancing the basic strategies based on remote or indirect measurements instead of in-place measuring the plant and soil parameters (a.k.a. Let the Plants do the Talking), associated with more standard information derived from environmental conditions.

Friday 30 june 2023

Engineered nanomaterials (ENMs) are now becoming a significant fraction of the material flows in the global economy, with applications in strategic sectors (sustainability, food production). Considering the potential exposure to plants and the environment, assessing the biological processes involved in the ENM response and effects at the level of organism, tissue, and cell is necessary. Applied strategies have been developed to combine genetics (mutant collections) and “omics” disciplines (genomics, transcriptomics, proteomics, and metabolomics) in model systems such as Arabidopsis thaliana and widely used crops (e.g., Solanum lycopersicum L., Cucurbita pepo L., Glycine max L.), to describe the molecular interactions between ENMs and living organisms: genotoxic effects, stress response pathways regulation, organellar functionality, genetic and epigenetic mechanisms.

The information gained becomes functional to develop Alternative Testing Strategies (ATS) correlated to assess and monitor the ENM exposure/effects, even at early stages, including molecular biomarkers (genes, miRNA, proteins, metabolites). “Omics”-based approaches can be instrumental in comprehending the mechanisms associated with the ENMs interaction in living organisms and in developing “safe by design” and more sustainable ENM applications.

Fertilization is an important and critical agricultural input. The introduction of large amounts of nutrients in the environment has several undesirable side effects. In fact, mineral fertilization is one of the inputs with the greatest impact on the health of ecosystems. It is estimated that up to 70% of nitrogen never reaches the crop. Also, numerous water quality problems have been associated with eutrophication due to phosphorous losses from the agroecosystems to freshwater bodies. An appropriate fertilizer application and placement method should aim at a rapid uptake to reduce the losses. The nutrient use efficiency can significantly vary by changing the fertilizers time, method and form of application. Within this context, nanotechnology is providing many revolutionary solutions aimed at reducing the negative environmental footprint of conventional mineral crop production.

The talk summarizes the potential uses and advantages as well as the role of nanotechnology in agriculture, highlighting the weaknesses, strengths, and research opportunities of this new approach.

Crop diseases caused by bacteria and fungi represent some of the most threatening production loss’ causes in agroecosystems. Agrochemicals, to control and prevent plant pathogens/diseases are largely used but now a strongly request for their reduction in order to preserve biodiversity, environment and consumers health, is requested. The application of nanotechnology in plant protection could play an import role to reach these goals minimizing the amount of agrochemicals and developing green nano-compounds. Nanotechnology-based materials are studied due to their unique properties including smart delivery, increased surface-volume ratio, better interaction with plant tissues and natural environment, controlled release and a role as carriers for active molecules. Here, the most recent and promising research lines highlighting the obtained results and also potential industrial scale up, economic and environmental sustainability related to new nano-compounds formulation for sustainable plant protection strategies.

It is estimated that 10% of the pesticides reach non-target areas. As part of the Green Deal, the European Commission adopted a proposal to reduce by 50% the use of pesticides by 2030. One effective strategy to reduce conventional pesticides is the employment of nanotechnology for innovative protection strategies. Nanoparticles have been used as gene delivery systems for transgenic and non-transgenic plant transformation, corresponding to crop improvement.

Interestingly, the nanoparticle gene-delivery system can also be directly sprayed on plant tissues, and the complexes shield DNA upon degradation. Therefore, this strategy could represent a superior technique for crop improvement. Since the European Commission restricted the employment of transgenic materials, this approach will be useful to transiently donor to plants a specific genetic resistance against a certain pathogen.

Traditional crop protection methods require repeated applications of large volumes of active ingredients at high initial dosages. Moreover, the non-controlled delivery of biocides causes time-limited protection and their ubiquitous presence in the environment, inducing biocide resistance and soil/water/food chain contamination. The controlled release of these biocides and of fertilisers represents thus a strategy to increase the efficiency of their delivery, reducing costs and pollution and improving environmental sustainability.

In this context, lignin-based micro- and nanocarriers loaded with these active ingredients are promising materials due to their biocompatibility and stimuli-responsive behaviour. After an introduction to lignin's structure and physicochemical properties, the main methodologies to synthesise nanoparticles and microcapsules will be discussed. Finally, some applications for nano-enabled agriculture will be presented.

Chitosan is one of the most abundant biopolymers on earth, together with cellulose, and is easily obtainable from chitin-based waste (crustaceans, fungi, insects) using circular economy processes. Therefore, considerable interest is conferred to its application in developing new technologies for eco-sustainability in agriculture, especially in synthesizing nanomaterials. Furthermore, it is known that its beneficial properties, such as the induction of biological responses concerning plant defense against stresses, are enhanced when the polymer is in a nanometric form. Furthermore, chitosan nanostructures show better interaction with plant teguments and an appreciated durability and stability; hence, they are also suitable as carriers for bioactive molecules to be used as new-generation agronomic formulates for crop nutrition or protection.

Given their potential in the future, this lesson will take an in-depth look at the properties and synthesis of chitosan nanoparticles, including some examples of plant pathology applications.