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Sensitive and molecular size-selective detection of proteins using a chip-based and heteroliganded gold nanoisland by localized surface plasmon resonance spectroscopy.

Hong S, Lee S, Yi J - Nanoscale Res Lett (2011)

Bottom Line: Their ratios on gold nanoisland were optimized for the sensitive detection of superoxide dismutase (SOD1).This protein has been implicated in the pathology of amyotrophic lateral sclerosis (ALS).Upon exposure of the optimized gold nanoisland to a solution of SOD1 and aggregates thereof, changes in the LSPR spectra were observed which are attributed to the size-selective and covalent chemical binding of SOD1 to the nanoholes.

View Article: PubMed Central - HTML - PubMed

Affiliation: World Class University (WCU) Program of Chemical Convergence for Energy & Environment (C2E2), School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 151-744, Korea. jyi@snu.ac.kr.

ABSTRACT
A highly sensitive and molecular size-selective method for the detection of proteins using heteroliganded gold nanoislands and localized surface plasmon resonance (LSPR) is described. Two different heteroligands with different chain lengths (3-mercaptopionicacid and decanethiol) were used in fabricating nanoholes for the size-dependent separation of a protein in comparison with its aggregate. Their ratios on gold nanoisland were optimized for the sensitive detection of superoxide dismutase (SOD1). This protein has been implicated in the pathology of amyotrophic lateral sclerosis (ALS). Upon exposure of the optimized gold nanoisland to a solution of SOD1 and aggregates thereof, changes in the LSPR spectra were observed which are attributed to the size-selective and covalent chemical binding of SOD1 to the nanoholes. With a lower detection limit of 1.0 ng/ml, the method can be used to selectively detect SOD1 in the presence of aggregates at the molecular level.

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Related in: MedlinePlus

Changes in the maximum absorbance peak as a function of mole fractions of MPA over DT in binary mixed SAM (ӼMPA + ӼDT = 1).
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Figure 2: Changes in the maximum absorbance peak as a function of mole fractions of MPA over DT in binary mixed SAM (ӼMPA + ӼDT = 1).

Mentions: Figure 2 shows changes in absorbance as a function of the mole fraction of MPA (semi-log scale) when nanoisland substrates with two different thicknesses (1, 5 nm) were exposed to an aqueous SOD1 protein solution (0.1 mg/ml) for 1 h, and then allowed to equilibrate after exposure to dry air, respectively. Among the different substrates, the changes in absorbance of the 5-nm nanoisland substrates were superior than that of the 1-nm substrates. This can be attributed to the more extensive coverage of gold nanoisland in the case of the 5-nm substrate. This would result in a stronger absorption efficiency of the electromagnetic field proportional to the imaginary part of polarizability [37]. A plot of sensitivity as a function of ratio shows that the sensitivity increases with the mole fraction, reaching a maximum change for a ӼMPA value of 0.01, and then drastically decreases. Therefore, the optimized gold nanoisland glass substrate was used to examine the sensitivity of the method for the detection of various concentrations of SOD1.


Sensitive and molecular size-selective detection of proteins using a chip-based and heteroliganded gold nanoisland by localized surface plasmon resonance spectroscopy.

Hong S, Lee S, Yi J - Nanoscale Res Lett (2011)

Changes in the maximum absorbance peak as a function of mole fractions of MPA over DT in binary mixed SAM (ӼMPA + ӼDT = 1).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211424&req=5

Figure 2: Changes in the maximum absorbance peak as a function of mole fractions of MPA over DT in binary mixed SAM (ӼMPA + ӼDT = 1).
Mentions: Figure 2 shows changes in absorbance as a function of the mole fraction of MPA (semi-log scale) when nanoisland substrates with two different thicknesses (1, 5 nm) were exposed to an aqueous SOD1 protein solution (0.1 mg/ml) for 1 h, and then allowed to equilibrate after exposure to dry air, respectively. Among the different substrates, the changes in absorbance of the 5-nm nanoisland substrates were superior than that of the 1-nm substrates. This can be attributed to the more extensive coverage of gold nanoisland in the case of the 5-nm substrate. This would result in a stronger absorption efficiency of the electromagnetic field proportional to the imaginary part of polarizability [37]. A plot of sensitivity as a function of ratio shows that the sensitivity increases with the mole fraction, reaching a maximum change for a ӼMPA value of 0.01, and then drastically decreases. Therefore, the optimized gold nanoisland glass substrate was used to examine the sensitivity of the method for the detection of various concentrations of SOD1.

Bottom Line: Their ratios on gold nanoisland were optimized for the sensitive detection of superoxide dismutase (SOD1).This protein has been implicated in the pathology of amyotrophic lateral sclerosis (ALS).Upon exposure of the optimized gold nanoisland to a solution of SOD1 and aggregates thereof, changes in the LSPR spectra were observed which are attributed to the size-selective and covalent chemical binding of SOD1 to the nanoholes.

View Article: PubMed Central - HTML - PubMed

Affiliation: World Class University (WCU) Program of Chemical Convergence for Energy & Environment (C2E2), School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 151-744, Korea. jyi@snu.ac.kr.

ABSTRACT
A highly sensitive and molecular size-selective method for the detection of proteins using heteroliganded gold nanoislands and localized surface plasmon resonance (LSPR) is described. Two different heteroligands with different chain lengths (3-mercaptopionicacid and decanethiol) were used in fabricating nanoholes for the size-dependent separation of a protein in comparison with its aggregate. Their ratios on gold nanoisland were optimized for the sensitive detection of superoxide dismutase (SOD1). This protein has been implicated in the pathology of amyotrophic lateral sclerosis (ALS). Upon exposure of the optimized gold nanoisland to a solution of SOD1 and aggregates thereof, changes in the LSPR spectra were observed which are attributed to the size-selective and covalent chemical binding of SOD1 to the nanoholes. With a lower detection limit of 1.0 ng/ml, the method can be used to selectively detect SOD1 in the presence of aggregates at the molecular level.

No MeSH data available.


Related in: MedlinePlus