Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young's modulus.
Measurements of Young's moduli are mostly evaluated using strong assumptions, such as sample homogeneity and isotropy. At the same time, descriptions of measurement parameters often lack detailed specifications. Many of these assumptions are, for soft hydrogels especially, not completely valid...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2019-01-01
|
| Series: | PLoS ONE |
| Online Access: | https://doi.org/10.1371/journal.pone.0220281 |
| _version_ | 1819108858483703808 |
|---|---|
| author | Steven Huth Sandra Sindt Christine Selhuber-Unkel |
| author_facet | Steven Huth Sandra Sindt Christine Selhuber-Unkel |
| author_sort | Steven Huth |
| collection | DOAJ |
| description | Measurements of Young's moduli are mostly evaluated using strong assumptions, such as sample homogeneity and isotropy. At the same time, descriptions of measurement parameters often lack detailed specifications. Many of these assumptions are, for soft hydrogels especially, not completely valid and the complexity of hydrogel microindentation demands more sophisticated experimental procedures in order to describe their elastic properties more accurately. We created an algorithm that automates indentation data analysis as a basis for the evaluation of large data sets with consideration of the influence of indentation depth on the measured Young's modulus. The algorithm automatically determines the Young's modulus in indentation regions where it becomes independent of the indentation depth and furthermore minimizes the error from fitting an elastic model to the data. This approach is independent of the chosen elastic fitting model and indentation device. With this, we are able to evaluate large amounts of indentation curves recorded on many different sample positions and can therefore apply statistical methods to overcome deviations due to sample inhomogeneities. To prove the applicability of our algorithm, we carried out a systematic analysis of how the indentation speed, indenter size and sample thickness affect the determination of Young's modulus from atomic force microscope (AFM) indentation curves on polyacrylamide (PAAm) samples. We chose the Hertz model as the elastic fitting model for this proof of principle of our algorithm and found that all of these parameters influence the measured Young's moduli to a certain extent. Hence, it is essential to clearly state the experimental parameters used in microindentation experiments to ensure reproducibility and comparability of data. |
| first_indexed | 2024-12-22T03:16:37Z |
| format | Article |
| id | doaj.art-0bfc4bb6a2874ab89c82dd35bbcb6e32 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-22T03:16:37Z |
| publishDate | 2019-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-0bfc4bb6a2874ab89c82dd35bbcb6e322022-12-21T18:40:49ZengPublic Library of Science (PLoS)PLoS ONE1932-62032019-01-01148e022028110.1371/journal.pone.0220281Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young's modulus.Steven HuthSandra SindtChristine Selhuber-UnkelMeasurements of Young's moduli are mostly evaluated using strong assumptions, such as sample homogeneity and isotropy. At the same time, descriptions of measurement parameters often lack detailed specifications. Many of these assumptions are, for soft hydrogels especially, not completely valid and the complexity of hydrogel microindentation demands more sophisticated experimental procedures in order to describe their elastic properties more accurately. We created an algorithm that automates indentation data analysis as a basis for the evaluation of large data sets with consideration of the influence of indentation depth on the measured Young's modulus. The algorithm automatically determines the Young's modulus in indentation regions where it becomes independent of the indentation depth and furthermore minimizes the error from fitting an elastic model to the data. This approach is independent of the chosen elastic fitting model and indentation device. With this, we are able to evaluate large amounts of indentation curves recorded on many different sample positions and can therefore apply statistical methods to overcome deviations due to sample inhomogeneities. To prove the applicability of our algorithm, we carried out a systematic analysis of how the indentation speed, indenter size and sample thickness affect the determination of Young's modulus from atomic force microscope (AFM) indentation curves on polyacrylamide (PAAm) samples. We chose the Hertz model as the elastic fitting model for this proof of principle of our algorithm and found that all of these parameters influence the measured Young's moduli to a certain extent. Hence, it is essential to clearly state the experimental parameters used in microindentation experiments to ensure reproducibility and comparability of data.https://doi.org/10.1371/journal.pone.0220281 |
| spellingShingle | Steven Huth Sandra Sindt Christine Selhuber-Unkel Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young's modulus. PLoS ONE |
| title | Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young's modulus. |
| title_full | Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young's modulus. |
| title_fullStr | Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young's modulus. |
| title_full_unstemmed | Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young's modulus. |
| title_short | Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young's modulus. |
| title_sort | automated analysis of soft hydrogel microindentation impact of various indentation parameters on the measurement of young s modulus |
| url | https://doi.org/10.1371/journal.pone.0220281 |
| work_keys_str_mv | AT stevenhuth automatedanalysisofsofthydrogelmicroindentationimpactofvariousindentationparametersonthemeasurementofyoungsmodulus AT sandrasindt automatedanalysisofsofthydrogelmicroindentationimpactofvariousindentationparametersonthemeasurementofyoungsmodulus AT christineselhuberunkel automatedanalysisofsofthydrogelmicroindentationimpactofvariousindentationparametersonthemeasurementofyoungsmodulus |