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Quantitative Characterization of Collagen in the Fibrotic Capsule Surrounding Implanted Polymeric Microparticles through Second Harmonic Generation Imaging.

Akilbekova D, Bratlie KM - PLoS ONE (2015)

Bottom Line: Data presented in this work shows a wide range of collagen fiber orientations and collagen compositions in response to surface functionalized polystyrene particles.Dimethylamino functionalized particles were able to form a thin collagenous matrix resembling healthy skin.These findings have the potential to improve the fundamental understanding of how material properties influence collagen organization and composition quantitatively.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science & Engineering, Iowa State University, Ames, Iowa 50011, United States of America.

ABSTRACT
The collagenous capsule formed around an implant will ultimately determine the nature of its in vivo fate. To provide a better understanding of how surface modifications can alter the collagen orientation and composition in the fibrotic capsule, we used second harmonic generation (SHG) microscopy to evaluate collagen organization and structure generated in mice subcutaneously injected with chemically functionalized polystyrene particles. SHG is sensitive to the orientation of a molecule, making it a powerful tool for measuring the alignment of collagen fibers. Additionally, SHG arises from the second order susceptibility of the interrogated molecule in response to the electric field. Variation in these tensor components distinguishes different molecular sources of SHG, providing collagen type specificity. Here, we demonstrated the ability of SHG to differentiate collagen type I and type III quantitatively and used this method to examine fibrous capsules of implanted polystyrene particles. Data presented in this work shows a wide range of collagen fiber orientations and collagen compositions in response to surface functionalized polystyrene particles. Dimethylamino functionalized particles were able to form a thin collagenous matrix resembling healthy skin. These findings have the potential to improve the fundamental understanding of how material properties influence collagen organization and composition quantitatively.

No MeSH data available.


Related in: MedlinePlus

A) Histograms of  values obtained for tissue sections of subcutaneously implanted aldehyde/sulfate, amidine, amino and dimethylamino polystyrene particles. The bars represent experimentally acquired data. The red line is the bimodal Gaussian fit to the data. B) Collagen type III content of fibrotic capsules surrounding subcutaneously implanted polystyrene particles.
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pone.0130386.g005: A) Histograms of values obtained for tissue sections of subcutaneously implanted aldehyde/sulfate, amidine, amino and dimethylamino polystyrene particles. The bars represent experimentally acquired data. The red line is the bimodal Gaussian fit to the data. B) Collagen type III content of fibrotic capsules surrounding subcutaneously implanted polystyrene particles.

Mentions: Structural inhomogenities were also quantified using SHG imaging. The gradient line obtained in Fig 1B was used to estimate the collagen type III % concentration in the fibrotic capsule surrounding the modified polystyrene particles (Fig 5A, S2 Table). Jain and co-workers [38] have previously examined matrigel, laminin, and collagen IV and found no SHG signal. This was further demonstrated by Nguyen-Ngoc and Ewald [39], who also reported an absence of signal from Matrigel. The analysis in this study assumes that the SHG signal arises from collagen type I and type III. Collagen type III peaks were observed for all tissue sections injected with polystyrene particles. The collagen type I and type III histogram peak assignments are given in S2 Table. Fibrotic capsules surrounding the unmodified polystyrene particles had the lowest content of collagen type III (17.55 ± 3.45%). Control tissue sections showed 35.05 ± 10.30% of collagen type III, which agrees with previously obtained results [11]. Amidine, carboxyl, and PMMA particles showed the highest level of collagen type III in their fibrotic capsule with around 50% of collagen type III (Fig 5B). The fibrotic capsules surrounding the amino, hydroxyl, and aldehyde/sulfate implanted particles had similar collagen type III content as the control tissue. Tissue sections were also stained for the presence of collagen types I and III (Fig 6) for qualitative confirmation of the SHG results. In the fibrous capsules surrounding dimethylamino and carboxyl, higher collagen type III content was noticed compared to polystyrene, hydroxyl, and the control skin tissue. While aldehyde/sulfate, amidine, amino, PMMA, and VBC showed similar level of collagen type III. Due to differences in quantum yields and molar absorptivities between the different fluorophores used, only qualitative descriptions of the immunohistochemistry images were possible.


Quantitative Characterization of Collagen in the Fibrotic Capsule Surrounding Implanted Polymeric Microparticles through Second Harmonic Generation Imaging.

Akilbekova D, Bratlie KM - PLoS ONE (2015)

A) Histograms of  values obtained for tissue sections of subcutaneously implanted aldehyde/sulfate, amidine, amino and dimethylamino polystyrene particles. The bars represent experimentally acquired data. The red line is the bimodal Gaussian fit to the data. B) Collagen type III content of fibrotic capsules surrounding subcutaneously implanted polystyrene particles.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488378&req=5

pone.0130386.g005: A) Histograms of values obtained for tissue sections of subcutaneously implanted aldehyde/sulfate, amidine, amino and dimethylamino polystyrene particles. The bars represent experimentally acquired data. The red line is the bimodal Gaussian fit to the data. B) Collagen type III content of fibrotic capsules surrounding subcutaneously implanted polystyrene particles.
Mentions: Structural inhomogenities were also quantified using SHG imaging. The gradient line obtained in Fig 1B was used to estimate the collagen type III % concentration in the fibrotic capsule surrounding the modified polystyrene particles (Fig 5A, S2 Table). Jain and co-workers [38] have previously examined matrigel, laminin, and collagen IV and found no SHG signal. This was further demonstrated by Nguyen-Ngoc and Ewald [39], who also reported an absence of signal from Matrigel. The analysis in this study assumes that the SHG signal arises from collagen type I and type III. Collagen type III peaks were observed for all tissue sections injected with polystyrene particles. The collagen type I and type III histogram peak assignments are given in S2 Table. Fibrotic capsules surrounding the unmodified polystyrene particles had the lowest content of collagen type III (17.55 ± 3.45%). Control tissue sections showed 35.05 ± 10.30% of collagen type III, which agrees with previously obtained results [11]. Amidine, carboxyl, and PMMA particles showed the highest level of collagen type III in their fibrotic capsule with around 50% of collagen type III (Fig 5B). The fibrotic capsules surrounding the amino, hydroxyl, and aldehyde/sulfate implanted particles had similar collagen type III content as the control tissue. Tissue sections were also stained for the presence of collagen types I and III (Fig 6) for qualitative confirmation of the SHG results. In the fibrous capsules surrounding dimethylamino and carboxyl, higher collagen type III content was noticed compared to polystyrene, hydroxyl, and the control skin tissue. While aldehyde/sulfate, amidine, amino, PMMA, and VBC showed similar level of collagen type III. Due to differences in quantum yields and molar absorptivities between the different fluorophores used, only qualitative descriptions of the immunohistochemistry images were possible.

Bottom Line: Data presented in this work shows a wide range of collagen fiber orientations and collagen compositions in response to surface functionalized polystyrene particles.Dimethylamino functionalized particles were able to form a thin collagenous matrix resembling healthy skin.These findings have the potential to improve the fundamental understanding of how material properties influence collagen organization and composition quantitatively.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science & Engineering, Iowa State University, Ames, Iowa 50011, United States of America.

ABSTRACT
The collagenous capsule formed around an implant will ultimately determine the nature of its in vivo fate. To provide a better understanding of how surface modifications can alter the collagen orientation and composition in the fibrotic capsule, we used second harmonic generation (SHG) microscopy to evaluate collagen organization and structure generated in mice subcutaneously injected with chemically functionalized polystyrene particles. SHG is sensitive to the orientation of a molecule, making it a powerful tool for measuring the alignment of collagen fibers. Additionally, SHG arises from the second order susceptibility of the interrogated molecule in response to the electric field. Variation in these tensor components distinguishes different molecular sources of SHG, providing collagen type specificity. Here, we demonstrated the ability of SHG to differentiate collagen type I and type III quantitatively and used this method to examine fibrous capsules of implanted polystyrene particles. Data presented in this work shows a wide range of collagen fiber orientations and collagen compositions in response to surface functionalized polystyrene particles. Dimethylamino functionalized particles were able to form a thin collagenous matrix resembling healthy skin. These findings have the potential to improve the fundamental understanding of how material properties influence collagen organization and composition quantitatively.

No MeSH data available.


Related in: MedlinePlus