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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) Plan-view scanning electron micrograph of an uncoated 20 nm pore size nanoporous alumina membrane after treatment with human platelet-rich plasma. (b) Energy-dispersive X-ray analysis spectrum for the uncoated nanoporous alumina membrane after treatment with human platelet-rich plasma. Protein adsorption and pore fouling were observed on the surface of the platelet-rich plasma-exposed membrane. Sodium chloride crystals were identified on the scanning electron micrograph; sodium and chlorine were noted on the energy-dispersive X-ray spectrum.
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RSTA20100011F9: (a) Plan-view scanning electron micrograph of an uncoated 20 nm pore size nanoporous alumina membrane after treatment with human platelet-rich plasma. (b) Energy-dispersive X-ray analysis spectrum for the uncoated nanoporous alumina membrane after treatment with human platelet-rich plasma. Protein adsorption and pore fouling were observed on the surface of the platelet-rich plasma-exposed membrane. Sodium chloride crystals were identified on the scanning electron micrograph; sodium and chlorine were noted on the energy-dispersive X-ray spectrum.

Mentions: A scanning electron micrograph of a PEGylated, platinum-coated (coating=8 nm) 20 nm pore size nanoporous alumina membrane after exposure to human platelet-rich plasma is shown in figure 7; no protein aggregation was observed on the surface. The pores of the PEGylated, platinum-coated nanoporous alumina membrane largely remained free of fouling. Scanning electron micrographs of a platinum-coated (coating=9 nm) 20 nm pore size nanoporous alumina membrane and an uncoated 20 nm pore size nanoporous alumina membrane after exposure to human platelet-rich plasma are shown in figures 8 and 9, respectively. Significant protein aggregation and pore fouling were observed on the surfaces of these membranes. In addition, small, widely scattered crystals were observed on the surfaces of the platinum-coated nanoporous alumina membrane and the uncoated nanoporous alumina membrane. The presence of sodium and chlorine in the energy-dispersive X-ray analysis spectra of the platinum-coated nanoporous alumina membrane and the uncoated nanoporous alumina membrane suggests that sodium chloride crystals precipitated from platelet-rich plasma during testing. Recent work by Andara et al. (2006) suggested that sodium chloride crystal adsorption is independent from protein adsorption. Tsapikouni & Missirlis (2008) noted that protein adsorption is governed by solution properties (e.g. pH), surface properties (e.g. surface energy) and protein properties (e.g. protein conformation). Previous studies have shown that polyethylene glycol is resistant to adsorption of proteins; for example, Jiang et al. (2004) demonstrated that self-assembled monolayers containing oligo(ethyleneglycol)-terminated alkanethiols resist adhesion of mammalian cells as well as non-specific adsorption of proteins; in their study, self-assembled monolayers containing oligo(ethyleneglycol)-terminated alkanethiols on palladium were shown to remain inert for at least four weeks. Seigel et al. (1997) utilized an acoustic plate-mode sensor in order to demonstrate that hexa(ethylene glycol)-terminated self-assembled monolayers demonstrate very low protein adsorption. Wang et al. (1997) suggested that oligo(ethylene glycol)-terminated self-assembled monolayers resist proteins and other biological molecules owing to the fact that these molecules form hydrogen bonds with water molecules. It is believed that a stable interfacial layer of water molecules inhibits protein–surface contact and prevents protein adsorption; as such, this process is considered to be enthalpic instead of entropic. These antifouling properties are appealing for implantable devices, since protein fouling and cell adhesion can impede transport of biological molecules between the device and the surrounding tissues.


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) Plan-view scanning electron micrograph of an uncoated 20 nm pore size nanoporous alumina membrane after treatment with human platelet-rich plasma. (b) Energy-dispersive X-ray analysis spectrum for the uncoated nanoporous alumina membrane after treatment with human platelet-rich plasma. Protein adsorption and pore fouling were observed on the surface of the platelet-rich plasma-exposed membrane. Sodium chloride crystals were identified on the scanning electron micrograph; sodium and chlorine were noted on the energy-dispersive X-ray spectrum.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

RSTA20100011F9: (a) Plan-view scanning electron micrograph of an uncoated 20 nm pore size nanoporous alumina membrane after treatment with human platelet-rich plasma. (b) Energy-dispersive X-ray analysis spectrum for the uncoated nanoporous alumina membrane after treatment with human platelet-rich plasma. Protein adsorption and pore fouling were observed on the surface of the platelet-rich plasma-exposed membrane. Sodium chloride crystals were identified on the scanning electron micrograph; sodium and chlorine were noted on the energy-dispersive X-ray spectrum.
Mentions: A scanning electron micrograph of a PEGylated, platinum-coated (coating=8 nm) 20 nm pore size nanoporous alumina membrane after exposure to human platelet-rich plasma is shown in figure 7; no protein aggregation was observed on the surface. The pores of the PEGylated, platinum-coated nanoporous alumina membrane largely remained free of fouling. Scanning electron micrographs of a platinum-coated (coating=9 nm) 20 nm pore size nanoporous alumina membrane and an uncoated 20 nm pore size nanoporous alumina membrane after exposure to human platelet-rich plasma are shown in figures 8 and 9, respectively. Significant protein aggregation and pore fouling were observed on the surfaces of these membranes. In addition, small, widely scattered crystals were observed on the surfaces of the platinum-coated nanoporous alumina membrane and the uncoated nanoporous alumina membrane. The presence of sodium and chlorine in the energy-dispersive X-ray analysis spectra of the platinum-coated nanoporous alumina membrane and the uncoated nanoporous alumina membrane suggests that sodium chloride crystals precipitated from platelet-rich plasma during testing. Recent work by Andara et al. (2006) suggested that sodium chloride crystal adsorption is independent from protein adsorption. Tsapikouni & Missirlis (2008) noted that protein adsorption is governed by solution properties (e.g. pH), surface properties (e.g. surface energy) and protein properties (e.g. protein conformation). Previous studies have shown that polyethylene glycol is resistant to adsorption of proteins; for example, Jiang et al. (2004) demonstrated that self-assembled monolayers containing oligo(ethyleneglycol)-terminated alkanethiols resist adhesion of mammalian cells as well as non-specific adsorption of proteins; in their study, self-assembled monolayers containing oligo(ethyleneglycol)-terminated alkanethiols on palladium were shown to remain inert for at least four weeks. Seigel et al. (1997) utilized an acoustic plate-mode sensor in order to demonstrate that hexa(ethylene glycol)-terminated self-assembled monolayers demonstrate very low protein adsorption. Wang et al. (1997) suggested that oligo(ethylene glycol)-terminated self-assembled monolayers resist proteins and other biological molecules owing to the fact that these molecules form hydrogen bonds with water molecules. It is believed that a stable interfacial layer of water molecules inhibits protein–surface contact and prevents protein adsorption; as such, this process is considered to be enthalpic instead of entropic. These antifouling properties are appealing for implantable devices, since protein fouling and cell adhesion can impede transport of biological molecules between the device and the surrounding tissues.

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