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Atomic layer deposition-based functionalization of materials for medical and environmental health applications.

Narayan RJ, Adiga SP, Pellin MJ, Curtiss LA, Hryn AJ, Stafslien S, Chisholm B, Shih CC, Shih CM, Lin SJ, Su YY, Jin C, Zhang J, Monteiro-Riviere NA, Elam JW - Philos Trans A Math Phys Eng Sci (2010)

Bottom Line: In addition, films deposited by means of atomic layer deposition may impart improved biological functionality to nanoporous alumina membranes.PEGylated nanoporous alumina membranes were prepared by self-assembly of 1-mercaptoundec-11-yl hexa(ethylene glycol) on platinum-coated nanoporous alumina membranes.The results of this work indicate that nanoporous alumina membranes may be modified using atomic layer deposition for use in a variety of medical and environmental health applications.

View Article: PubMed Central - PubMed

Affiliation: Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, 2147 Burlington Engineering Labs, Raleigh, NC 27695-7115, USA. roger_narayan@msn.com

ABSTRACT
Nanoporous alumina membranes exhibit high pore densities, well-controlled and uniform pore sizes, as well as straight pores. Owing to these unusual properties, nanoporous alumina membranes are currently being considered for use in implantable sensor membranes and water purification membranes. Atomic layer deposition is a thin-film growth process that may be used to modify the pore size in a nanoporous alumina membrane while retaining a narrow pore distribution. In addition, films deposited by means of atomic layer deposition may impart improved biological functionality to nanoporous alumina membranes. In this study, zinc oxide coatings and platinum coatings were deposited on nanoporous alumina membranes by means of atomic layer deposition. PEGylated nanoporous alumina membranes were prepared by self-assembly of 1-mercaptoundec-11-yl hexa(ethylene glycol) on platinum-coated nanoporous alumina membranes. The pores of the PEGylated nanoporous alumina membranes remained free of fouling after exposure to human platelet-rich plasma; protein adsorption, fibrin networks and platelet aggregation were not observed on the coated membrane surface. Zinc oxide-coated nanoporous alumina membranes demonstrated activity against two waterborne pathogens, Escherichia coli and Staphylococcus aureus. The results of this work indicate that nanoporous alumina membranes may be modified using atomic layer deposition for use in a variety of medical and environmental health applications.

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Plan-view scanning electron micrograph of a zinc oxide-coated (coating= 5 nm) 100 nm pore size nanoporous alumina membrane.
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RSTA20100011F10: Plan-view scanning electron micrograph of a zinc oxide-coated (coating= 5 nm) 100 nm pore size nanoporous alumina membrane.

Mentions: Figure 10 shows a plan-view scanning electron micrograph of a 100 nm pore size nanoporous alumina membrane following atomic layer deposition of a 5 nm zinc oxide coating. This figure demonstrates that the nanoporous alumina membrane coated with zinc oxide using atomic layer deposition exhibited monodisperse pore sizes and high porosity. Figure 11 shows cross-sectional scanning electron micrographs obtained from a cleaved nanoporous alumina membrane following atomic layer deposition of a 5 nm thick zinc oxide coating. Figure 11b indicates that the alumina pore structure is not completely uniform; branching of pores as well as intersections of pores are shown. Figure 11c shows that the inner surfaces of the pores are completely coated with zinc oxide nanocrystals that exhibit dimensions between 5 and 10 nm. In addition, cross-sectional energy-dispersive X-ray analysis was performed across the membrane thickness; the zinc oxide concentration was shown to be uniform throughout the membrane. Figure 12 shows an X-ray diffraction pattern for a nanoporous alumina membrane following atomic layer deposition of a 5 nm zinc oxide coating. The peaks in this figure match the expected positions for hexagonal zincite, which are described in File 36-1451 of the Joint Committee on Powder Diffraction Standards (2000). The size of the zinc oxide crystals was estimated from peak widths using the Scherrer formula to be 8 nm. Uncoated nanoporous alumina membranes are composed of amorphous alumina and impurities; X-ray diffraction measurements performed on uncoated nanoporous alumina membranes yielded no peaks. Figure 13a contains an X-ray photoelectron spectrum of an uncoated 100 nm pore size nanoporous alumina membrane. Figure 13b contains an X-ray photoelectron spectrum of a zinc oxide-coated (coating=5 nm) 100 nm pore size nanoporous alumina membrane. The characteristic 2p peak for aluminium (binding energy=74 eV) was not detected in the spectrum of the zinc oxide-coated nanoporous alumina membrane. Analysis using CasaXPS software (RBD Instruments, Bend, USA) confirmed the absence of aluminium; the zinc oxide coating was shown to be continuous and was shown to completely cover the nanoporous alumina membrane surface.


Atomic layer deposition-based functionalization of materials for medical and environmental health applications.

Narayan RJ, Adiga SP, Pellin MJ, Curtiss LA, Hryn AJ, Stafslien S, Chisholm B, Shih CC, Shih CM, Lin SJ, Su YY, Jin C, Zhang J, Monteiro-Riviere NA, Elam JW - Philos Trans A Math Phys Eng Sci (2010)

Plan-view scanning electron micrograph of a zinc oxide-coated (coating= 5 nm) 100 nm pore size nanoporous alumina membrane.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2944392&req=5

RSTA20100011F10: Plan-view scanning electron micrograph of a zinc oxide-coated (coating= 5 nm) 100 nm pore size nanoporous alumina membrane.
Mentions: Figure 10 shows a plan-view scanning electron micrograph of a 100 nm pore size nanoporous alumina membrane following atomic layer deposition of a 5 nm zinc oxide coating. This figure demonstrates that the nanoporous alumina membrane coated with zinc oxide using atomic layer deposition exhibited monodisperse pore sizes and high porosity. Figure 11 shows cross-sectional scanning electron micrographs obtained from a cleaved nanoporous alumina membrane following atomic layer deposition of a 5 nm thick zinc oxide coating. Figure 11b indicates that the alumina pore structure is not completely uniform; branching of pores as well as intersections of pores are shown. Figure 11c shows that the inner surfaces of the pores are completely coated with zinc oxide nanocrystals that exhibit dimensions between 5 and 10 nm. In addition, cross-sectional energy-dispersive X-ray analysis was performed across the membrane thickness; the zinc oxide concentration was shown to be uniform throughout the membrane. Figure 12 shows an X-ray diffraction pattern for a nanoporous alumina membrane following atomic layer deposition of a 5 nm zinc oxide coating. The peaks in this figure match the expected positions for hexagonal zincite, which are described in File 36-1451 of the Joint Committee on Powder Diffraction Standards (2000). The size of the zinc oxide crystals was estimated from peak widths using the Scherrer formula to be 8 nm. Uncoated nanoporous alumina membranes are composed of amorphous alumina and impurities; X-ray diffraction measurements performed on uncoated nanoporous alumina membranes yielded no peaks. Figure 13a contains an X-ray photoelectron spectrum of an uncoated 100 nm pore size nanoporous alumina membrane. Figure 13b contains an X-ray photoelectron spectrum of a zinc oxide-coated (coating=5 nm) 100 nm pore size nanoporous alumina membrane. The characteristic 2p peak for aluminium (binding energy=74 eV) was not detected in the spectrum of the zinc oxide-coated nanoporous alumina membrane. Analysis using CasaXPS software (RBD Instruments, Bend, USA) confirmed the absence of aluminium; the zinc oxide coating was shown to be continuous and was shown to completely cover the nanoporous alumina membrane surface.

Bottom Line: In addition, films deposited by means of atomic layer deposition may impart improved biological functionality to nanoporous alumina membranes.PEGylated nanoporous alumina membranes were prepared by self-assembly of 1-mercaptoundec-11-yl hexa(ethylene glycol) on platinum-coated nanoporous alumina membranes.The results of this work indicate that nanoporous alumina membranes may be modified using atomic layer deposition for use in a variety of medical and environmental health applications.

View Article: PubMed Central - PubMed

Affiliation: Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, 2147 Burlington Engineering Labs, Raleigh, NC 27695-7115, USA. roger_narayan@msn.com

ABSTRACT
Nanoporous alumina membranes exhibit high pore densities, well-controlled and uniform pore sizes, as well as straight pores. Owing to these unusual properties, nanoporous alumina membranes are currently being considered for use in implantable sensor membranes and water purification membranes. Atomic layer deposition is a thin-film growth process that may be used to modify the pore size in a nanoporous alumina membrane while retaining a narrow pore distribution. In addition, films deposited by means of atomic layer deposition may impart improved biological functionality to nanoporous alumina membranes. In this study, zinc oxide coatings and platinum coatings were deposited on nanoporous alumina membranes by means of atomic layer deposition. PEGylated nanoporous alumina membranes were prepared by self-assembly of 1-mercaptoundec-11-yl hexa(ethylene glycol) on platinum-coated nanoporous alumina membranes. The pores of the PEGylated nanoporous alumina membranes remained free of fouling after exposure to human platelet-rich plasma; protein adsorption, fibrin networks and platelet aggregation were not observed on the coated membrane surface. Zinc oxide-coated nanoporous alumina membranes demonstrated activity against two waterborne pathogens, Escherichia coli and Staphylococcus aureus. The results of this work indicate that nanoporous alumina membranes may be modified using atomic layer deposition for use in a variety of medical and environmental health applications.

Show MeSH
Related in: MedlinePlus