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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

(A) Schematic view of a heteroliganded gold nanoisland for the sensitive and molecular size-selective detection of a protein. The enlarged schematic diagram shows the surface morphology of a heteroliganded gold nanoisland and the binding principle of a protein in the presence of its aggregates. (B) (a) The detection method via chip-based localized surface plasmon resonance spectroscopy. (b) The before (black) and after (red) absorption spectra of the gold nanoislands after a 1-h exposure to a 0.1 mg/ml solution of SOD1.
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Figure 1: (A) Schematic view of a heteroliganded gold nanoisland for the sensitive and molecular size-selective detection of a protein. The enlarged schematic diagram shows the surface morphology of a heteroliganded gold nanoisland and the binding principle of a protein in the presence of its aggregates. (B) (a) The detection method via chip-based localized surface plasmon resonance spectroscopy. (b) The before (black) and after (red) absorption spectra of the gold nanoislands after a 1-h exposure to a 0.1 mg/ml solution of SOD1.

Mentions: We examined the feasibility of a chip-based gold nanoisland sensor prepared for the sensitive and molecular size-selective detection of a protein. A schematic view of the heteroliganded gold nanoisland and the basic scheme underlying the sensor operation are shown in Figure 1. The gold nanoisland was prepared by thermal evaporation on a transparent substrate. After annealing procedure of the surface, dimensions of the gold nanoislands were in the range of 40-80 nm in diameter [26,27]. The binary SAM containing MPA and DT was fabricated on the gold nanoislands. Because the two thiol derivaties, MPA and DT, have different hydrophilicities as well as different chain lengths, the nanometer-scale phase separation on the surface would form a binary mixture due to ω-functional group interaction [28-31]. The mole fractions of these molecules on the gold nanoisland in the fabrication of the mixed SAM were optimized so as to maximize the sensitivity of the method. The phase separated and nanometer-scaled MPA domains in the mixed SAM induce the formation of nanoholes [32-35], which would play an important role as effective binding sites of native SOD1 compared to aggregates. The dimensions of SOD1 aggregates cultured by TFE condition for 4 weeks was determined to be in the several hundred nanometer scales to the micrometer scales [36]. Because of this, it is not possible for them to enter the MPA nanoholes.


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)

(A) Schematic view of a heteroliganded gold nanoisland for the sensitive and molecular size-selective detection of a protein. The enlarged schematic diagram shows the surface morphology of a heteroliganded gold nanoisland and the binding principle of a protein in the presence of its aggregates. (B) (a) The detection method via chip-based localized surface plasmon resonance spectroscopy. (b) The before (black) and after (red) absorption spectra of the gold nanoislands after a 1-h exposure to a 0.1 mg/ml solution of SOD1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: (A) Schematic view of a heteroliganded gold nanoisland for the sensitive and molecular size-selective detection of a protein. The enlarged schematic diagram shows the surface morphology of a heteroliganded gold nanoisland and the binding principle of a protein in the presence of its aggregates. (B) (a) The detection method via chip-based localized surface plasmon resonance spectroscopy. (b) The before (black) and after (red) absorption spectra of the gold nanoislands after a 1-h exposure to a 0.1 mg/ml solution of SOD1.
Mentions: We examined the feasibility of a chip-based gold nanoisland sensor prepared for the sensitive and molecular size-selective detection of a protein. A schematic view of the heteroliganded gold nanoisland and the basic scheme underlying the sensor operation are shown in Figure 1. The gold nanoisland was prepared by thermal evaporation on a transparent substrate. After annealing procedure of the surface, dimensions of the gold nanoislands were in the range of 40-80 nm in diameter [26,27]. The binary SAM containing MPA and DT was fabricated on the gold nanoislands. Because the two thiol derivaties, MPA and DT, have different hydrophilicities as well as different chain lengths, the nanometer-scale phase separation on the surface would form a binary mixture due to ω-functional group interaction [28-31]. The mole fractions of these molecules on the gold nanoisland in the fabrication of the mixed SAM were optimized so as to maximize the sensitivity of the method. The phase separated and nanometer-scaled MPA domains in the mixed SAM induce the formation of nanoholes [32-35], which would play an important role as effective binding sites of native SOD1 compared to aggregates. The dimensions of SOD1 aggregates cultured by TFE condition for 4 weeks was determined to be in the several hundred nanometer scales to the micrometer scales [36]. Because of this, it is not possible for them to enter the MPA nanoholes.

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