Understanding the impact of micro and nanoplastics on the environment and the living organisms is becoming increasingly pressing, as highlighted by the exponential growth of literature regarding these pollutants. Nanoplastics form in the environment due to natural degradation processes of plastic wastes, such as photodegradation, mechanical fragmentation and biodegradation. However, environmental samples are difficult to manage, because of the extremely complexity, heterogeneity and the high level of natural impurities. For this reason, to date fundamental studies are mostly conducted by using model synthetic nanobeads, instead of natural nanoplastics. Moreover, almost all literature available on nanobeads is based on polystyrene nanobeads; however, nanoplastics in the environment are expected to derive from a variety of waste polymers. There is the need to create nanomaterials that better reflect the real characteristics of nanoplastics naturally formed, to close the gap between the laboratory practice and the rules of nature, and to provide more realistic understandings of the characteristics of nanoplastics. In this thesis, plastic nanoparticles obtained by mechanical fragmentation in cryogenic conditions of daily-life plastic items, “true-to-life” nanoplastics (T2LNPs), are proposed as a better reference nanomaterial for the study of environmental nanoplastics. Chapter 1 outlines the topic of the research project, related to the environmental plastic pollution and the degradation processes that lead to the formation of microplastics and nanoplastics. The state of the art in the study of nanoplastics is also discussed. In Chapter 2, the developed protocol for the production of polystyrene T2LNPs by means of mechanical fragmentation is described. A complete morphological and physical–chemical characterization of PS-T2LNPs is presented. In Chapter 3, preliminary tests for the quantification of PS-T2LNPs are discussed. Chapter 4 presents the investigation of PS-T2LNPs behavior at the biological interface, in comparison to the behavior of polystyrene nanobeads. Chapter 5 focuses on polymeric materials different from polystyrene. T2LNPs of polyethylene terephthalate (PET) and polyamide 66 (PA66) are produced and characterized adapting the protocols developed for polystyrene, including mechanical fragmentation, morphological and physical–chemical characterization and the investigation of biological interactions. Chapter 6 summarizes the principal results of the research work and introduces future developments and perspectives. Complementary activities regarding the sustainability evaluation of new processes / materials have also been conducted during the PhD period. These evaluations, partially related to the main core of PhD research, are discussed in the Appendix of the thesis. Appendix A briefly discusses the concepts of sustainability evaluation and circular economy and presents a new tool, named ESCAPE, for early sustainability assessment of new materials, at research and development stages. Appendix B discusses three proof-of-concept studies of the proposed ESCAPE tool. This work is framed in an interdisciplinary collaboration between the Chemistry for Technologies Laboratory, Department of Mechanical and Industrial Engineering, and the Clinical Biochemistry and Clinical Molecular Biology Laboratory, Department of Molecular and Translational Medicine, of the University of Brescia. The research was funded by PON “R&I” 2014-2020: SIRIMAP—SIstemi di Rilevamento dell’Inquinamento MArino da Plastiche e successivo recupero-riciclo (No. ARS01_01183, CUP D86C18000520008) and partially based upon work from COST Action CA20101 Plastics monitoRIng detectiOn RemedIaTion recoverY - PRIORITY, supported by COST (European Cooperation in Science and Technology). www.cost.eu.
Comprendere l'impatto delle micro- e nanoplastiche sugli ecosistemi sta diventando sempre più importante, come evidenziato dalla crescita esponenziale della letteratura scientifica riguardante questi inquinanti. Le nanoplastiche si formano in ambiente a causa di processi naturali di degradazione dei rifiuti plastici. Tuttavia, i campioni ambientali sono difficili da gestire, a causa della loro complessità, eterogeneità e dell'alto livello di impurità naturali. Per questo motivo, la gran parte degli studi condotti finora si basa sull’utilizzo di nanoparticelle sintetiche, come modelli delle nanoplastiche naturali. Inoltre, quasi tutti gli studi pubblicati si basano su nanoparticelle di polistirene; tuttavia, è verosimile ritenere che le nanoplastiche naturalmente formate in ambiente derivino da una varietà di rifiuti plastici. È necessario creare nanomateriali che meglio rispecchino le caratteristiche delle nanoplastiche naturalmente formate, per colmare il divario tra la pratica di laboratorio e le regole della natura e per fornire una comprensione più realistica delle caratteristiche delle nanoplastiche. In questa tesi viene proposto un nuovo nanomateriale di riferimento per lo studio delle nanoplastiche ambientali, nominato “true-to-life nanoplastics” (T2LNPs), ottenuto per frammentazione meccanica in condizioni criogeniche di oggetti plastici di uso quotidiano. Nel Capitolo 1 viene descritto l’ambito di questo progetto di ricerca, ovvero l’inquinamento ambientale da plastica e i processi di degradazione che portano alla formazione di microplastiche e nanoplastiche. Viene anche presentato lo stato dell’arte riguardante lo studio delle nanoplastiche. Nel Capitolo 2 viene descritto il protocollo sviluppato in questo studio per la produzione di “T2LNPs” di polistirene, mediante frammentazione meccanica. Viene inoltre presentata una caratterizzazione morfologica e fisico-chimica dei campioni prodotti. Nel Capitolo 3 vengono discusse le prove preliminari condotte per la quantificazione dei campioni. Nel Capitolo 4 vengono presentati i risultati dello studio sull’interazione biologica dei campioni di “T2LNPs” in confronto alle nanoparticelle sintetiche di polistirene. Nel Capitolo 5 viene presentato lo studio sulla produzione e caratterizzazione di campioni “T2LNPs” di polietilene tereftalato (PET) e poliammide 66 (PA66), condotto adattando i protocolli sviluppati per lo studio del polistirene, comprensivi di frammentazione meccanica, caratterizzazione morfologica e fisico-chimica e studio delle interazioni biologiche. Il capitolo 6 riassume i principali risultati di questo lavoro di ricerca e introduce gli sviluppi e le prospettive futuri. A complemento dello studio sui materiali di riferimento per le nanoplastiche, durante il periodo di dottorato sono stati anche condotti studi relativi alla valutazione della sostenibilità di nuovi processi/materiali. Tali valutazioni, in parte correlate all’ambito principale della tesi, sono discusse in appendice alla tesi. Nell'Appendice A vengono brevemente introdotti i concetti di valutazione della sostenibilità ed economia circolare e viene proposto un nuovo strumento, denominato ESCAPE, per la valutazione precoce della sostenibilità di un nuovo materiale, nelle fasi di ricerca e sviluppo. Nell'Appendice B vengono discussi tre studi “proof-of-concept” per validare il metodo ESCAPE. Questo lavoro nasce da una collaborazione interdisciplinare tra il Laboratorio di Chimica per le Tecnologie DIMI, e il Laboratorio di Biochimica clinica e Biologia molecolare clinica DMMT, dell'Università degli Studi di Brescia. La ricerca è stata finanziata dal PON “R&I” 2014-2020: SIRIMAP—SIstemi di Rilevamento dell'Inquinamento MArino da Plastiche e successivo recupero-riciclo (N. ARS01_01183, CUP D86C18000520008) ed è in parte basata su COST Action CA20101 Plastics monitoring detectioniOn RemedIaTION recovery - PRIORITY.
Development of new reference nanomaterials for environmental plastic pollution and assessment of interactions with biological systems / Ducoli, Serena. - (2022 Jun 09).
Development of new reference nanomaterials for environmental plastic pollution and assessment of interactions with biological systems
DUCOLI, SERENA
2022-06-09
Abstract
Understanding the impact of micro and nanoplastics on the environment and the living organisms is becoming increasingly pressing, as highlighted by the exponential growth of literature regarding these pollutants. Nanoplastics form in the environment due to natural degradation processes of plastic wastes, such as photodegradation, mechanical fragmentation and biodegradation. However, environmental samples are difficult to manage, because of the extremely complexity, heterogeneity and the high level of natural impurities. For this reason, to date fundamental studies are mostly conducted by using model synthetic nanobeads, instead of natural nanoplastics. Moreover, almost all literature available on nanobeads is based on polystyrene nanobeads; however, nanoplastics in the environment are expected to derive from a variety of waste polymers. There is the need to create nanomaterials that better reflect the real characteristics of nanoplastics naturally formed, to close the gap between the laboratory practice and the rules of nature, and to provide more realistic understandings of the characteristics of nanoplastics. In this thesis, plastic nanoparticles obtained by mechanical fragmentation in cryogenic conditions of daily-life plastic items, “true-to-life” nanoplastics (T2LNPs), are proposed as a better reference nanomaterial for the study of environmental nanoplastics. Chapter 1 outlines the topic of the research project, related to the environmental plastic pollution and the degradation processes that lead to the formation of microplastics and nanoplastics. The state of the art in the study of nanoplastics is also discussed. In Chapter 2, the developed protocol for the production of polystyrene T2LNPs by means of mechanical fragmentation is described. A complete morphological and physical–chemical characterization of PS-T2LNPs is presented. In Chapter 3, preliminary tests for the quantification of PS-T2LNPs are discussed. Chapter 4 presents the investigation of PS-T2LNPs behavior at the biological interface, in comparison to the behavior of polystyrene nanobeads. Chapter 5 focuses on polymeric materials different from polystyrene. T2LNPs of polyethylene terephthalate (PET) and polyamide 66 (PA66) are produced and characterized adapting the protocols developed for polystyrene, including mechanical fragmentation, morphological and physical–chemical characterization and the investigation of biological interactions. Chapter 6 summarizes the principal results of the research work and introduces future developments and perspectives. Complementary activities regarding the sustainability evaluation of new processes / materials have also been conducted during the PhD period. These evaluations, partially related to the main core of PhD research, are discussed in the Appendix of the thesis. Appendix A briefly discusses the concepts of sustainability evaluation and circular economy and presents a new tool, named ESCAPE, for early sustainability assessment of new materials, at research and development stages. Appendix B discusses three proof-of-concept studies of the proposed ESCAPE tool. This work is framed in an interdisciplinary collaboration between the Chemistry for Technologies Laboratory, Department of Mechanical and Industrial Engineering, and the Clinical Biochemistry and Clinical Molecular Biology Laboratory, Department of Molecular and Translational Medicine, of the University of Brescia. The research was funded by PON “R&I” 2014-2020: SIRIMAP—SIstemi di Rilevamento dell’Inquinamento MArino da Plastiche e successivo recupero-riciclo (No. ARS01_01183, CUP D86C18000520008) and partially based upon work from COST Action CA20101 Plastics monitoRIng detectiOn RemedIaTion recoverY - PRIORITY, supported by COST (European Cooperation in Science and Technology). www.cost.eu.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
