Nano-Scale Stiffness and Collagen Fibril Deterioration: Probing the Cornea Following Enzymatic Degradation Using Peakforce-QNM AFM
Under physiological conditions, the cornea is exposed to various enzymes, some of them have digestive actions, such as amylase and collagenase that may change the ultrastructure (collagen morphology) and sequentially change the mechanical response of the cornea and distort vision, such as in keratoc...
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MDPI AG
2021-02-01
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| Online Access: | https://www.mdpi.com/1424-8220/21/5/1629 |
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| author | Ahmed Kazaili Hayder Abdul-Amir Al-Hindy Jillian Madine Riaz Akhtar |
| author_facet | Ahmed Kazaili Hayder Abdul-Amir Al-Hindy Jillian Madine Riaz Akhtar |
| author_sort | Ahmed Kazaili |
| collection | DOAJ |
| description | Under physiological conditions, the cornea is exposed to various enzymes, some of them have digestive actions, such as amylase and collagenase that may change the ultrastructure (collagen morphology) and sequentially change the mechanical response of the cornea and distort vision, such as in keratoconus. This study investigates the ultrastructure and nanomechanical properties of porcine cornea following incubation with α-amylase and collagenase. Atomic force microscopy (AFM) was used to capture nanoscale topographical details of stromal collagen fibrils (diameter and D-periodicity) and calculate their elastic modulus. Samples were incubated with varying concentrations of α-amylase and collagenase (crude and purified). Dimethylmethylene blue (DMMB) assay was utilised to detect depleted glycosaminoglycans (GAGs) following incubation with amylase. Collagen fibril diameters were decreased following incubation with amylase, but not D-periodicity. Elastic modulus was gradually decreased with enzyme concentration in amylase-treated samples. Elastic modulus, diameter, and D-periodicity were greatly reduced in collagenase-treated samples. The effect of crude collagenase on corneal samples was more pronounced than purified collagenase. Amylase was found to deplete GAGs from the samples. This enzymatic treatment may help in answering some questions related to keratoconus, and possibly be used to build an empirical animal model of keratoconic corneas with different progression levels. |
| first_indexed | 2024-03-09T00:31:12Z |
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| id | doaj.art-228c21f69e3e48a3873f3672c0c3dcf4 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-09T00:31:12Z |
| publishDate | 2021-02-01 |
| publisher | MDPI AG |
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| series | Sensors |
| spelling | doaj.art-228c21f69e3e48a3873f3672c0c3dcf42023-12-11T18:31:04ZengMDPI AGSensors1424-82202021-02-01215162910.3390/s21051629Nano-Scale Stiffness and Collagen Fibril Deterioration: Probing the Cornea Following Enzymatic Degradation Using Peakforce-QNM AFMAhmed Kazaili0Hayder Abdul-Amir Al-Hindy1Jillian Madine2Riaz Akhtar3Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool L69 3GH, UKCollege of Pharmacy, University of Babylon, Babylon, Hillah 51002, IraqDepartment of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7BE, UKDepartment of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool L69 3GH, UKUnder physiological conditions, the cornea is exposed to various enzymes, some of them have digestive actions, such as amylase and collagenase that may change the ultrastructure (collagen morphology) and sequentially change the mechanical response of the cornea and distort vision, such as in keratoconus. This study investigates the ultrastructure and nanomechanical properties of porcine cornea following incubation with α-amylase and collagenase. Atomic force microscopy (AFM) was used to capture nanoscale topographical details of stromal collagen fibrils (diameter and D-periodicity) and calculate their elastic modulus. Samples were incubated with varying concentrations of α-amylase and collagenase (crude and purified). Dimethylmethylene blue (DMMB) assay was utilised to detect depleted glycosaminoglycans (GAGs) following incubation with amylase. Collagen fibril diameters were decreased following incubation with amylase, but not D-periodicity. Elastic modulus was gradually decreased with enzyme concentration in amylase-treated samples. Elastic modulus, diameter, and D-periodicity were greatly reduced in collagenase-treated samples. The effect of crude collagenase on corneal samples was more pronounced than purified collagenase. Amylase was found to deplete GAGs from the samples. This enzymatic treatment may help in answering some questions related to keratoconus, and possibly be used to build an empirical animal model of keratoconic corneas with different progression levels.https://www.mdpi.com/1424-8220/21/5/1629Peakforce-QNMAFMcorneacollagenaseamylasenanomechanics |
| spellingShingle | Ahmed Kazaili Hayder Abdul-Amir Al-Hindy Jillian Madine Riaz Akhtar Nano-Scale Stiffness and Collagen Fibril Deterioration: Probing the Cornea Following Enzymatic Degradation Using Peakforce-QNM AFM Sensors Peakforce-QNM AFM cornea collagenase amylase nanomechanics |
| title | Nano-Scale Stiffness and Collagen Fibril Deterioration: Probing the Cornea Following Enzymatic Degradation Using Peakforce-QNM AFM |
| title_full | Nano-Scale Stiffness and Collagen Fibril Deterioration: Probing the Cornea Following Enzymatic Degradation Using Peakforce-QNM AFM |
| title_fullStr | Nano-Scale Stiffness and Collagen Fibril Deterioration: Probing the Cornea Following Enzymatic Degradation Using Peakforce-QNM AFM |
| title_full_unstemmed | Nano-Scale Stiffness and Collagen Fibril Deterioration: Probing the Cornea Following Enzymatic Degradation Using Peakforce-QNM AFM |
| title_short | Nano-Scale Stiffness and Collagen Fibril Deterioration: Probing the Cornea Following Enzymatic Degradation Using Peakforce-QNM AFM |
| title_sort | nano scale stiffness and collagen fibril deterioration probing the cornea following enzymatic degradation using peakforce qnm afm |
| topic | Peakforce-QNM AFM cornea collagenase amylase nanomechanics |
| url | https://www.mdpi.com/1424-8220/21/5/1629 |
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