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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

Synthetic route toward PHEMA brushes patterned through OPT, advanced lithography, and ATRP on Si wafers
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Sch1: Synthetic route toward PHEMA brushes patterned through OPT, advanced lithography, and ATRP on Si wafers

Mentions: The basic strategy for the fabrication of the patterned polymer brushes using the VLSI process has been described previously [24]. The fabrication of the patterned HEMA brushes using the VLSI process is depicted as shown in Scheme 1. In Scheme 1 (a), the Si wafer was treated with hexamethyldisilazane (HMDS) in a thermal evaporator (Track MK-8) at 90 °C for 30 s to transform the OH groups on the surface of the wafer into an inert film of Si(CH3)3 groups. In Scheme 1 (b), The photoresist was spun on the HMDS-treated Si wafer at a thickness of 780 nm. Advanced lithography was then used to pattern the photoresist with an array of trenches having dimensions ranging from 200 nm to 10 μm after development. In Scheme 1 (c), the sample was then subjected to oxygen plasma treatment (OPT) using a TCP 9400SE instrument (Lam Research Co, Ltd.) to form OH groups from the HMDS-treated surface. The plasma power supply was set to 300 W at a frequency of 13.5 MHz. The substrate was placed on the bottom electrode with the Si(100) surface exposed to the glow discharge at an O2 pressure of approximately 5 × 10−3 Torr for a predetermined period of time to form peroxide and hydroxide species for the subsequent graft polymerization experiment. OPT caused the surface to become chemically modified (strongly hydrophilic or polar) only in the areas not covered by the photoresist [28, 29]. The introduction of these polar groups provided a more wettable surface for the preparation of a self-assembled monolayer (SAM) for graft polymerization. In Scheme 1 (d), the Si substrate treated with HMDS and O2 plasma was immersed in a 0.5% (w/v) solution of BPOTS in toluene for 3 h at 50 °C to immobilize the ATRP initiator (BPOTS). The BPOTS units were assembled selectively onto the bare regions of the Si surface after OPT, where it reacted with SiO and SiOO species. This procedure resulted in a surface patterned with regions of BPOTS for ATRP and regions of photoresist. The functionalized Si substrates were removed from the solution, washed with toluene for 15 min to remove any unreacted material, dried under a stream of N2, and subjected to surface-initiated polymerization reactions. Finally, the surfaces were dried under vacuum and stored under dry N2. In Scheme 1 (e), the patterned PHEMA brushes were grafted on the initiator-modified Si surface by ATRP.Scheme 1


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

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

Synthetic route toward PHEMA brushes patterned through OPT, advanced lithography, and ATRP on Si wafers
© Copyright Policy
Related In: Results  -  Collection

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

Sch1: Synthetic route toward PHEMA brushes patterned through OPT, advanced lithography, and ATRP on Si wafers
Mentions: The basic strategy for the fabrication of the patterned polymer brushes using the VLSI process has been described previously [24]. The fabrication of the patterned HEMA brushes using the VLSI process is depicted as shown in Scheme 1. In Scheme 1 (a), the Si wafer was treated with hexamethyldisilazane (HMDS) in a thermal evaporator (Track MK-8) at 90 °C for 30 s to transform the OH groups on the surface of the wafer into an inert film of Si(CH3)3 groups. In Scheme 1 (b), The photoresist was spun on the HMDS-treated Si wafer at a thickness of 780 nm. Advanced lithography was then used to pattern the photoresist with an array of trenches having dimensions ranging from 200 nm to 10 μm after development. In Scheme 1 (c), the sample was then subjected to oxygen plasma treatment (OPT) using a TCP 9400SE instrument (Lam Research Co, Ltd.) to form OH groups from the HMDS-treated surface. The plasma power supply was set to 300 W at a frequency of 13.5 MHz. The substrate was placed on the bottom electrode with the Si(100) surface exposed to the glow discharge at an O2 pressure of approximately 5 × 10−3 Torr for a predetermined period of time to form peroxide and hydroxide species for the subsequent graft polymerization experiment. OPT caused the surface to become chemically modified (strongly hydrophilic or polar) only in the areas not covered by the photoresist [28, 29]. The introduction of these polar groups provided a more wettable surface for the preparation of a self-assembled monolayer (SAM) for graft polymerization. In Scheme 1 (d), the Si substrate treated with HMDS and O2 plasma was immersed in a 0.5% (w/v) solution of BPOTS in toluene for 3 h at 50 °C to immobilize the ATRP initiator (BPOTS). The BPOTS units were assembled selectively onto the bare regions of the Si surface after OPT, where it reacted with SiO and SiOO species. This procedure resulted in a surface patterned with regions of BPOTS for ATRP and regions of photoresist. The functionalized Si substrates were removed from the solution, washed with toluene for 15 min to remove any unreacted material, dried under a stream of N2, and subjected to surface-initiated polymerization reactions. Finally, the surfaces were dried under vacuum and stored under dry N2. In Scheme 1 (e), the patterned PHEMA brushes were grafted on the initiator-modified Si surface by ATRP.Scheme 1

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