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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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(a) Cross-sectional scanning electron micrograph obtained from a cleaved specimen of a nanoporous alumina membrane following atomic layer deposition of an 8 nm platinum coating. (b) High-resolution scanning electron micrograph at the middle of the pore shows a partially continuous platinum coating. (c) High-resolution scanning electron micrograph near the large pore edge shows a continuous platinum coating.
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RSTA20100011F2: (a) Cross-sectional scanning electron micrograph obtained from a cleaved specimen of a nanoporous alumina membrane following atomic layer deposition of an 8 nm platinum coating. (b) High-resolution scanning electron micrograph at the middle of the pore shows a partially continuous platinum coating. (c) High-resolution scanning electron micrograph near the large pore edge shows a continuous platinum coating.

Mentions: Figure 1a shows a plan-view scanning electron micrograph of a 20 nm pore size nanoporous alumina membrane following atomic layer deposition of an 8 nm platinum coating, which was obtained from the large pore side of the membrane. Figure 1b shows a plan-view scanning electron micrograph of a nanoporous alumina membrane following atomic layer deposition of an 8 nm platinum coating; the image was obtained from the small pore side of the membrane. These figures demonstrate that the nanoporous alumina membrane coated with platinum using atomic layer deposition exhibited a monodisperse pore size and high porosity. Figure 2 shows a cross-sectional scanning electron micrograph obtained from a cleaved 20 nm pore size nanoporous alumina membrane following atomic layer deposition of an 8 nm thick platinum coating. The coating is continuous near the ends of the pore (figure 2b); fairly uniform contrast was noted. Images obtained from near the small pore side of the platinum-coated nanoporous alumina membrane (data not shown) have a similar appearance. Figure 2c indicates that the platinum coating is partially continuous at the middle of the pore; uncoated regions of the nanoporous alumina membrane were observed. In order to evaluate the continuity of the platinum coating, electrical resistance through the nanoporous alumina membrane was determined using a digital ohmmeter; measurements were obtained by pressing the platinum-coated nanoporous alumina membrane between conductive metal plates. The resistance of the platinum-coated nanoporous alumina membranes was approximately 1Ω; in comparison, an immeasurably high resistance (greater than 20 MΩ) was obtained for the uncoated nanoporous alumina membranes. This result indicates that the platinum coating is partially continuous in nature. Figure 3 shows a high-resolution scanning electron micrograph obtained at the middle of the pore, which shows the island structure of the partially continuous platinum coating; platinum coatings prepared using atomic layer deposition typically consist of agglomerated platinum nanoparticles.


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)

(a) Cross-sectional scanning electron micrograph obtained from a cleaved specimen of a nanoporous alumina membrane following atomic layer deposition of an 8 nm platinum coating. (b) High-resolution scanning electron micrograph at the middle of the pore shows a partially continuous platinum coating. (c) High-resolution scanning electron micrograph near the large pore edge shows a continuous platinum coating.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

RSTA20100011F2: (a) Cross-sectional scanning electron micrograph obtained from a cleaved specimen of a nanoporous alumina membrane following atomic layer deposition of an 8 nm platinum coating. (b) High-resolution scanning electron micrograph at the middle of the pore shows a partially continuous platinum coating. (c) High-resolution scanning electron micrograph near the large pore edge shows a continuous platinum coating.
Mentions: Figure 1a shows a plan-view scanning electron micrograph of a 20 nm pore size nanoporous alumina membrane following atomic layer deposition of an 8 nm platinum coating, which was obtained from the large pore side of the membrane. Figure 1b shows a plan-view scanning electron micrograph of a nanoporous alumina membrane following atomic layer deposition of an 8 nm platinum coating; the image was obtained from the small pore side of the membrane. These figures demonstrate that the nanoporous alumina membrane coated with platinum using atomic layer deposition exhibited a monodisperse pore size and high porosity. Figure 2 shows a cross-sectional scanning electron micrograph obtained from a cleaved 20 nm pore size nanoporous alumina membrane following atomic layer deposition of an 8 nm thick platinum coating. The coating is continuous near the ends of the pore (figure 2b); fairly uniform contrast was noted. Images obtained from near the small pore side of the platinum-coated nanoporous alumina membrane (data not shown) have a similar appearance. Figure 2c indicates that the platinum coating is partially continuous at the middle of the pore; uncoated regions of the nanoporous alumina membrane were observed. In order to evaluate the continuity of the platinum coating, electrical resistance through the nanoporous alumina membrane was determined using a digital ohmmeter; measurements were obtained by pressing the platinum-coated nanoporous alumina membrane between conductive metal plates. The resistance of the platinum-coated nanoporous alumina membranes was approximately 1Ω; in comparison, an immeasurably high resistance (greater than 20 MΩ) was obtained for the uncoated nanoporous alumina membranes. This result indicates that the platinum coating is partially continuous in nature. Figure 3 shows a high-resolution scanning electron micrograph obtained at the middle of the pore, which shows the island structure of the partially continuous platinum coating; platinum coatings prepared using atomic layer deposition typically consist of agglomerated platinum nanoparticles.

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