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Ferritin immobilization on patterned poly(2-hydroxyethyl methacrylate) brushes on silicon surfaces from colloid system.

Chen TY, Chen JK - Colloid Polym Sci (2011)

Bottom Line: The interaction between PHEMA and ferritin protein sheaths in MeOH and n-hexane (good and poor solvent for PHEMA, respectively) was used to capture and release ferritins from fluidic system.The "tentacles" behaver for PHEMA brushes was found through various solvents in fluidic system.Using high-resolution scanning electron microscopy, we observed patterned ferritin Fe cores on the Si surface after pyrolysis of the patterned PHEMA brushes and ferritin protein sheaths, which verify the "tentacles" behaver for PHEMA brushes.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Sec 4, Keelung Rd, Taipei, 106 Taiwan Republic of China.

ABSTRACT
In this paper, we describe a graft polymerization/solvent immersion method for generating poly(2-hydroxyethyl methacrylate) (PHEMA) brushes in various patterns. We used a novel fabrication process, involving very-large-scale integration and oxygen plasma treatment, to generate well-defined patterns of polymerized PHEMA on patterned Si(100) surfaces. We observed brush- and mushroom-like regions for the PHEMA brushes, with various pattern resolutions, after immersing wafers presenting lines of these polymers in MeOH and n-hexane, respectively. The interaction between PHEMA and ferritin protein sheaths in MeOH and n-hexane (good and poor solvent for PHEMA, respectively) was used to capture and release ferritins from fluidic system. The "tentacles" behaver for PHEMA brushes was found through various solvents in fluidic system. Using high-resolution scanning electron microscopy, we observed patterned ferritin Fe cores on the Si surface after pyrolysis of the patterned PHEMA brushes and ferritin protein sheaths, which verify the "tentacles" behaver for PHEMA brushes.

No MeSH data available.


Related in: MedlinePlus

Dependence of the thickness of the PHEMA layer, grown from the Si-BPOTS surface via ATRP
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Fig5: Dependence of the thickness of the PHEMA layer, grown from the Si-BPOTS surface via ATRP

Mentions: In a previous study, we used XPS analysis to investigate the presence of grafted PHEMA brushes on Si surfaces [28]. The C 1s core-level spectrum of the PHEMA brushes on the Si surface could be curve-fitted to three peak components having BEs of approximately 284.6, 286.4, and 288.8 eV, attributable to C–H, C–O, and O = C–O species, respectively. For the HEMA homopolymer, the theoretical [O]/[C] and [CH]/[C–O]/[O = C–O] ratios are 0.5 and 4:1:1, respectively. The corresponding ratios of 0.46 and 3.7:1.1:1, respectively, obtained through XPS analysis of the Si-BPOTS-PHEMA surface, are in fairly good agreement with the theoretical ratios. The Si surface presenting the PHEMA graft layer exhibited a water contact angle of approximately 73.3°, which is equivalent to a surface energy of 41.1 mN/m (Table 1) [36]. Because ATRP is a “living” polymerization process, we expected that the thickness of the polymer brushes would increase linearly upon increasing the polymerization time and the molecular weight of the graft polymer. We found, however, that the thickness of the PHEMA brushes was affected by whether it had been immersed in n-hexane or MeOH. Figure 5 displays the thicknesses of the PHEMA brushes grafted for various times onto the Si-BPOTS surfaces, recorded after ultrasonication in n-hexane or MeOH for 3 h. We observe approximately linear increases in thickness of the grafted PHEMA layer on the Si-BPOTS surface upon increasing the polymerization time to 12 h, after immersion in either n-hexane or MeOH. The thickness reached a plateau, indicating the formation of mushroom-like regimes of PHEMA brushes, after poor solvent (n-hexane) immersion of the polymer obtained after polymerization for more than 12 h (filled squares). In contrast, the thickness of the PHEMA brushes grafted on the Si substrate after MeOH immersion continued to increase upon increasing the polymerization time beyond 12 h, providing a brush-like regime of PHEMA brushes (empty squares). These observations reveal that the PHEMA brushes formed mushroom- and brush-like regimes after immersion in n-hexane or MeOH, respectively, consistent with the results of a previous study [37]. The thickness of the PHEMA brushes after immersion in the good solvent (MeOH) increased nearly linearly upon increasing the polymerization time because of the extension of the PHEMA brushes into a brush-like regime. Our results obtained after solvent immersion indicate that the process of surface-initiated ATRP of HEMA is controlled between two regimes for PHEMA brushes.Fig. 5


Ferritin immobilization on patterned poly(2-hydroxyethyl methacrylate) brushes on silicon surfaces from colloid system.

Chen TY, Chen JK - Colloid Polym Sci (2011)

Dependence of the thickness of the PHEMA layer, grown from the Si-BPOTS surface via ATRP
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040805&req=5

Fig5: Dependence of the thickness of the PHEMA layer, grown from the Si-BPOTS surface via ATRP
Mentions: In a previous study, we used XPS analysis to investigate the presence of grafted PHEMA brushes on Si surfaces [28]. The C 1s core-level spectrum of the PHEMA brushes on the Si surface could be curve-fitted to three peak components having BEs of approximately 284.6, 286.4, and 288.8 eV, attributable to C–H, C–O, and O = C–O species, respectively. For the HEMA homopolymer, the theoretical [O]/[C] and [CH]/[C–O]/[O = C–O] ratios are 0.5 and 4:1:1, respectively. The corresponding ratios of 0.46 and 3.7:1.1:1, respectively, obtained through XPS analysis of the Si-BPOTS-PHEMA surface, are in fairly good agreement with the theoretical ratios. The Si surface presenting the PHEMA graft layer exhibited a water contact angle of approximately 73.3°, which is equivalent to a surface energy of 41.1 mN/m (Table 1) [36]. Because ATRP is a “living” polymerization process, we expected that the thickness of the polymer brushes would increase linearly upon increasing the polymerization time and the molecular weight of the graft polymer. We found, however, that the thickness of the PHEMA brushes was affected by whether it had been immersed in n-hexane or MeOH. Figure 5 displays the thicknesses of the PHEMA brushes grafted for various times onto the Si-BPOTS surfaces, recorded after ultrasonication in n-hexane or MeOH for 3 h. We observe approximately linear increases in thickness of the grafted PHEMA layer on the Si-BPOTS surface upon increasing the polymerization time to 12 h, after immersion in either n-hexane or MeOH. The thickness reached a plateau, indicating the formation of mushroom-like regimes of PHEMA brushes, after poor solvent (n-hexane) immersion of the polymer obtained after polymerization for more than 12 h (filled squares). In contrast, the thickness of the PHEMA brushes grafted on the Si substrate after MeOH immersion continued to increase upon increasing the polymerization time beyond 12 h, providing a brush-like regime of PHEMA brushes (empty squares). These observations reveal that the PHEMA brushes formed mushroom- and brush-like regimes after immersion in n-hexane or MeOH, respectively, consistent with the results of a previous study [37]. The thickness of the PHEMA brushes after immersion in the good solvent (MeOH) increased nearly linearly upon increasing the polymerization time because of the extension of the PHEMA brushes into a brush-like regime. Our results obtained after solvent immersion indicate that the process of surface-initiated ATRP of HEMA is controlled between two regimes for PHEMA brushes.Fig. 5

Bottom Line: The interaction between PHEMA and ferritin protein sheaths in MeOH and n-hexane (good and poor solvent for PHEMA, respectively) was used to capture and release ferritins from fluidic system.The "tentacles" behaver for PHEMA brushes was found through various solvents in fluidic system.Using high-resolution scanning electron microscopy, we observed patterned ferritin Fe cores on the Si surface after pyrolysis of the patterned PHEMA brushes and ferritin protein sheaths, which verify the "tentacles" behaver for PHEMA brushes.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Sec 4, Keelung Rd, Taipei, 106 Taiwan Republic of China.

ABSTRACT
In this paper, we describe a graft polymerization/solvent immersion method for generating poly(2-hydroxyethyl methacrylate) (PHEMA) brushes in various patterns. We used a novel fabrication process, involving very-large-scale integration and oxygen plasma treatment, to generate well-defined patterns of polymerized PHEMA on patterned Si(100) surfaces. We observed brush- and mushroom-like regions for the PHEMA brushes, with various pattern resolutions, after immersing wafers presenting lines of these polymers in MeOH and n-hexane, respectively. The interaction between PHEMA and ferritin protein sheaths in MeOH and n-hexane (good and poor solvent for PHEMA, respectively) was used to capture and release ferritins from fluidic system. The "tentacles" behaver for PHEMA brushes was found through various solvents in fluidic system. Using high-resolution scanning electron microscopy, we observed patterned ferritin Fe cores on the Si surface after pyrolysis of the patterned PHEMA brushes and ferritin protein sheaths, which verify the "tentacles" behaver for PHEMA brushes.

No MeSH data available.


Related in: MedlinePlus