A Novel Approach for Identifying Nanoplastics by Assessing Deformation Behavior with Scanning Electron Microscopy
As plastic production continues to increase globally, plastic waste accumulates and degrades into smaller plastic particles. Through chemical and biological processes, nanoscale plastic particles (nanoplastics) are formed and are expected to exist in quantities of several orders of magnitude greater...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-10-01
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| Series: | Micromachines |
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| Online Access: | https://www.mdpi.com/2072-666X/14/10/1903 |
| _version_ | 1797572902097256448 |
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| author | Jared S. Stine Nicolas Aziere Bryan J. Harper Stacey L. Harper |
| author_facet | Jared S. Stine Nicolas Aziere Bryan J. Harper Stacey L. Harper |
| author_sort | Jared S. Stine |
| collection | DOAJ |
| description | As plastic production continues to increase globally, plastic waste accumulates and degrades into smaller plastic particles. Through chemical and biological processes, nanoscale plastic particles (nanoplastics) are formed and are expected to exist in quantities of several orders of magnitude greater than those found for microplastics. Due to their small size and low mass, nanoplastics remain challenging to detect in the environment using most standard analytical methods. The goal of this research is to adapt existing tools to address the analytical challenges posed by the identification of nanoplastics. Given the unique and well-documented properties of anthropogenic plastics, we hypothesized that nanoplastics could be differentiated by polymer type using spatiotemporal deformation data collected through irradiation with scanning electron microscopy (SEM). We selected polyvinyl chloride (PVC), polyethylene terephthalate (PET), and high-density polyethylene (HDPE) to capture a range of thermodynamic properties and molecular structures encompassed by commercially available plastics. Pristine samples of each polymer type were chosen and individually milled to generate micro and nanoscale particles for SEM analysis. To test the hypothesis that polymers could be differentiated from other constituents in complex samples, the polymers were compared against proxy materials common in environmental media, i.e., algae, kaolinite clay, and nanocellulose. Samples for SEM analysis were prepared uncoated to enable observation of polymer deformation under set electron beam parameters. For each sample type, particles approximately 1 µm in diameter were chosen, and videos of particle deformation were recorded and studied. Blinded samples were also prepared with mixtures of the aforementioned materials to test the viability of this method for identifying near-nanoscale plastic particles in environmental media. Based on the evidence collected, deformation patterns between plastic particles and particles present in common environmental media show significant differences. A computer vision algorithm was also developed and tested against manual measurements to improve the usefulness and efficiency of this method further. |
| first_indexed | 2024-03-10T21:02:17Z |
| format | Article |
| id | doaj.art-17c2037bcecb4159be12bb91ec6c0c79 |
| institution | Directory Open Access Journal |
| issn | 2072-666X |
| language | English |
| last_indexed | 2024-03-10T21:02:17Z |
| publishDate | 2023-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Micromachines |
| spelling | doaj.art-17c2037bcecb4159be12bb91ec6c0c792023-11-19T17:24:34ZengMDPI AGMicromachines2072-666X2023-10-011410190310.3390/mi14101903A Novel Approach for Identifying Nanoplastics by Assessing Deformation Behavior with Scanning Electron MicroscopyJared S. Stine0Nicolas Aziere1Bryan J. Harper2Stacey L. Harper3School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USASchool of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331, USADepartment of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, USASchool of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USAAs plastic production continues to increase globally, plastic waste accumulates and degrades into smaller plastic particles. Through chemical and biological processes, nanoscale plastic particles (nanoplastics) are formed and are expected to exist in quantities of several orders of magnitude greater than those found for microplastics. Due to their small size and low mass, nanoplastics remain challenging to detect in the environment using most standard analytical methods. The goal of this research is to adapt existing tools to address the analytical challenges posed by the identification of nanoplastics. Given the unique and well-documented properties of anthropogenic plastics, we hypothesized that nanoplastics could be differentiated by polymer type using spatiotemporal deformation data collected through irradiation with scanning electron microscopy (SEM). We selected polyvinyl chloride (PVC), polyethylene terephthalate (PET), and high-density polyethylene (HDPE) to capture a range of thermodynamic properties and molecular structures encompassed by commercially available plastics. Pristine samples of each polymer type were chosen and individually milled to generate micro and nanoscale particles for SEM analysis. To test the hypothesis that polymers could be differentiated from other constituents in complex samples, the polymers were compared against proxy materials common in environmental media, i.e., algae, kaolinite clay, and nanocellulose. Samples for SEM analysis were prepared uncoated to enable observation of polymer deformation under set electron beam parameters. For each sample type, particles approximately 1 µm in diameter were chosen, and videos of particle deformation were recorded and studied. Blinded samples were also prepared with mixtures of the aforementioned materials to test the viability of this method for identifying near-nanoscale plastic particles in environmental media. Based on the evidence collected, deformation patterns between plastic particles and particles present in common environmental media show significant differences. A computer vision algorithm was also developed and tested against manual measurements to improve the usefulness and efficiency of this method further.https://www.mdpi.com/2072-666X/14/10/1903SEMdetectionmicroplasticsmachine learningpolymers |
| spellingShingle | Jared S. Stine Nicolas Aziere Bryan J. Harper Stacey L. Harper A Novel Approach for Identifying Nanoplastics by Assessing Deformation Behavior with Scanning Electron Microscopy Micromachines SEM detection microplastics machine learning polymers |
| title | A Novel Approach for Identifying Nanoplastics by Assessing Deformation Behavior with Scanning Electron Microscopy |
| title_full | A Novel Approach for Identifying Nanoplastics by Assessing Deformation Behavior with Scanning Electron Microscopy |
| title_fullStr | A Novel Approach for Identifying Nanoplastics by Assessing Deformation Behavior with Scanning Electron Microscopy |
| title_full_unstemmed | A Novel Approach for Identifying Nanoplastics by Assessing Deformation Behavior with Scanning Electron Microscopy |
| title_short | A Novel Approach for Identifying Nanoplastics by Assessing Deformation Behavior with Scanning Electron Microscopy |
| title_sort | novel approach for identifying nanoplastics by assessing deformation behavior with scanning electron microscopy |
| topic | SEM detection microplastics machine learning polymers |
| url | https://www.mdpi.com/2072-666X/14/10/1903 |
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