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Modification of hydrophilic and hydrophobic surfaces using an ionic-complementary peptide.

Yang H, Fung SY, Pritzker M, Chen P - PLoS ONE (2007)

Bottom Line: In contrast, the water contact angle decreases significantly from 71.2+/-11.1 degrees to 39.4+/-4.3 degrees after the HOPG surface is coated with a 29 microM peptide solution for 2 h.The stability of the EAK16-II nanofibers on both surfaces is further evaluated by immersing the surface into acidic and basic solutions and analyzing the changes in the nanofiber surface coverage.This work demonstrates the possibility of using self-assembling peptides for surface modification applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada.

ABSTRACT
Ionic-complementary peptides are novel nano-biomaterials with a variety of biomedical applications including potential biosurface engineering. This study presents evidence that a model ionic-complementary peptide EAK16-II is capable of assembling/coating on hydrophilic mica as well as hydrophobic highly ordered pyrolytic graphite (HOPG) surfaces with different nano-patterns. EAK16-II forms randomly oriented nanofibers or nanofiber networks on mica, while ordered nanofibers parallel or oriented 60 degrees or 120 degrees to each other on HOPG, reflecting the crystallographic symmetry of graphite (0001). The density of coated nanofibers on both surfaces can be controlled by adjusting the peptide concentration and the contact time of the peptide solution with the surface. The coated EAK16-II nanofibers alter the wettability of the two surfaces differently: the water contact angle of bare mica surface is measured to be <10 degrees , while it increases to 20.3+/-2.9 degrees upon 2 h modification of the surface using a 29 microM EAK16-II solution. In contrast, the water contact angle decreases significantly from 71.2+/-11.1 degrees to 39.4+/-4.3 degrees after the HOPG surface is coated with a 29 microM peptide solution for 2 h. The stability of the EAK16-II nanofibers on both surfaces is further evaluated by immersing the surface into acidic and basic solutions and analyzing the changes in the nanofiber surface coverage. The EAK16-II nanofibers on mica remain stable in acidic solution but not in alkaline solution, while they are stable on the HOPG surface regardless of the solution pH. This work demonstrates the possibility of using self-assembling peptides for surface modification applications.

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Related in: MedlinePlus

Time evolution of 4 µM EAK16-II assembly on the mica surface.AFM images collected at various incubation times: (a) 1 min; (b) 2 min; (c) 5 min; (d) 10 min; (e) 20 min; (f) 40 min; (g) 80 min; (h) 120 min; (i) 160 min. Surface coverage of EAK16-II on mica as a function of incubation time is plotted in panel (j). Each image corresponds to a scan area of 2000 nm×2000 nm.
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pone-0001325-g002: Time evolution of 4 µM EAK16-II assembly on the mica surface.AFM images collected at various incubation times: (a) 1 min; (b) 2 min; (c) 5 min; (d) 10 min; (e) 20 min; (f) 40 min; (g) 80 min; (h) 120 min; (i) 160 min. Surface coverage of EAK16-II on mica as a function of incubation time is plotted in panel (j). Each image corresponds to a scan area of 2000 nm×2000 nm.

Mentions: The AFM images (Figure 2 panels a–i) show that EAK16-II can adhere to a mica surface and assemble into nanofibers after a certain time in pure water. In the presence of 4 µM EAK16-II, a few single and unbranched short fibers are observed after 1 min of incubation (Figure 2a). With time, the fibers appearing on the mica surface become longer and more numerous (Figures 2b and c). After 10 min, fiber networks are observed (Figures 2d–i). The evolution of the surface coverage of EAK16-II nanofibers with the incubation time is plotted in Figure 2j. The surface coverage of EAK16-II nanofibers increases rapidly with time over the first 30 or 40 min before leveling off to a plateau of about 27% after ∼1 h, indicating that saturation has been reached.


Modification of hydrophilic and hydrophobic surfaces using an ionic-complementary peptide.

Yang H, Fung SY, Pritzker M, Chen P - PLoS ONE (2007)

Time evolution of 4 µM EAK16-II assembly on the mica surface.AFM images collected at various incubation times: (a) 1 min; (b) 2 min; (c) 5 min; (d) 10 min; (e) 20 min; (f) 40 min; (g) 80 min; (h) 120 min; (i) 160 min. Surface coverage of EAK16-II on mica as a function of incubation time is plotted in panel (j). Each image corresponds to a scan area of 2000 nm×2000 nm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2117347&req=5

pone-0001325-g002: Time evolution of 4 µM EAK16-II assembly on the mica surface.AFM images collected at various incubation times: (a) 1 min; (b) 2 min; (c) 5 min; (d) 10 min; (e) 20 min; (f) 40 min; (g) 80 min; (h) 120 min; (i) 160 min. Surface coverage of EAK16-II on mica as a function of incubation time is plotted in panel (j). Each image corresponds to a scan area of 2000 nm×2000 nm.
Mentions: The AFM images (Figure 2 panels a–i) show that EAK16-II can adhere to a mica surface and assemble into nanofibers after a certain time in pure water. In the presence of 4 µM EAK16-II, a few single and unbranched short fibers are observed after 1 min of incubation (Figure 2a). With time, the fibers appearing on the mica surface become longer and more numerous (Figures 2b and c). After 10 min, fiber networks are observed (Figures 2d–i). The evolution of the surface coverage of EAK16-II nanofibers with the incubation time is plotted in Figure 2j. The surface coverage of EAK16-II nanofibers increases rapidly with time over the first 30 or 40 min before leveling off to a plateau of about 27% after ∼1 h, indicating that saturation has been reached.

Bottom Line: In contrast, the water contact angle decreases significantly from 71.2+/-11.1 degrees to 39.4+/-4.3 degrees after the HOPG surface is coated with a 29 microM peptide solution for 2 h.The stability of the EAK16-II nanofibers on both surfaces is further evaluated by immersing the surface into acidic and basic solutions and analyzing the changes in the nanofiber surface coverage.This work demonstrates the possibility of using self-assembling peptides for surface modification applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada.

ABSTRACT
Ionic-complementary peptides are novel nano-biomaterials with a variety of biomedical applications including potential biosurface engineering. This study presents evidence that a model ionic-complementary peptide EAK16-II is capable of assembling/coating on hydrophilic mica as well as hydrophobic highly ordered pyrolytic graphite (HOPG) surfaces with different nano-patterns. EAK16-II forms randomly oriented nanofibers or nanofiber networks on mica, while ordered nanofibers parallel or oriented 60 degrees or 120 degrees to each other on HOPG, reflecting the crystallographic symmetry of graphite (0001). The density of coated nanofibers on both surfaces can be controlled by adjusting the peptide concentration and the contact time of the peptide solution with the surface. The coated EAK16-II nanofibers alter the wettability of the two surfaces differently: the water contact angle of bare mica surface is measured to be <10 degrees , while it increases to 20.3+/-2.9 degrees upon 2 h modification of the surface using a 29 microM EAK16-II solution. In contrast, the water contact angle decreases significantly from 71.2+/-11.1 degrees to 39.4+/-4.3 degrees after the HOPG surface is coated with a 29 microM peptide solution for 2 h. The stability of the EAK16-II nanofibers on both surfaces is further evaluated by immersing the surface into acidic and basic solutions and analyzing the changes in the nanofiber surface coverage. The EAK16-II nanofibers on mica remain stable in acidic solution but not in alkaline solution, while they are stable on the HOPG surface regardless of the solution pH. This work demonstrates the possibility of using self-assembling peptides for surface modification applications.

Show MeSH
Related in: MedlinePlus