Analysis of alkanethiolates on gold with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Kim, Sungryung; Oh, Hongseok; Yeo, Woon‐Seok

doi:10.1007/s13765-015-0018-x

Cited by 13 publications

(5 citation statements)

References 70 publications

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“…The monolayer formation and subsequent removal of the protecting group were verified by MALDI-TOF MS and contact angle measurement. MALDI-TOF MS has been effectively used to analyze SAMs on gold, a process termed SAMDI MS, which provided information regarding the molecular weights of the alkanethiolates in SAMs. − MALDI analysis of PCB–QA-presenting SAMs showed a major peak at m / z 900.8 [M] + corresponding to the PCB–QA heterodisulfide (Figure S2a, top left panel). After treatment with 0.5 M KOH solution, MS analysis of the monolayer showed that the peak at m / z 900.8 was absent and that new peaks at m / z 462.3 [M] + and m / z 490.4 [M] + arose, corresponding to CB–QA heterodisulfide and QA-terminated homodisulfide (Figure S2a, bottom left panel).…”

Section: Resultsmentioning

confidence: 99%

On-Demand Modulation of Bacterial Cell Fates on Multifunctional Dynamic Substrates

Choi¹,

Lee²,

Kim

et al. 2018

ACS Appl. Mater. Interfaces

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This paper reports unprecedented dynamic surfaces based on zwitterionic low-density self-assembled monolayers (LDSAMs) of alkanethiolates on gold, which integrate three interconvertible states-bacteria-adherable, bactericidal, and nonfouling states-through electrical modulations. The conformations of alkanethiolates were electrically modulated to generate zwitterionic, anionic, and cationic surfaces, which responded differently to bacteria and determined the fate of bacteria. Furthermore, the reversible switching of multifunctions of the surface was realized for killing bacteria and subsequently releasing dead bacteria from the surface. For practical application of our strategy, we examined the selective antibacterial effect of our surface for eradication of mycoplasma contaminants in contaminated mammalian cell cultures.

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Section: Resultsmentioning

confidence: 99%

On-Demand Modulation of Bacterial Cell Fates on Multifunctional Dynamic Substrates

Choi¹,

Lee²,

Kim

et al. 2018

ACS Appl. Mater. Interfaces

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“…Combination of self‐assembled monolayers (SAMs) on gold and matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐TOF MS) termed SAMDI MS 1–3 permits identification of the mass changes on alkanethiolates, and thus, rapid tracking of chemical/biochemical conversions on the monolayer. Thus, SAMDI MS has been used to monitor chemical and biological reactions of immobilized substrates on surfaces, for the discovery of new organic reactions, 4–10 the assay of enzyme activity and the discovery of new enzymes 10–18 .…”

Section: Methodsmentioning

confidence: 99%

Tetrahydrofuran Highly Enhances SAMDI Efficiency

Yoo

Kang

Kim

et al. 2020

Bulletin Korean Chem Soc

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“…We first verified the surface modifications of the AuNPs and gold chips by using matrix-assisted LDI-TOF MS. [18][19][20] AuNPs were modified so as to have carboxylic acid functionality among Am-tag or dAm-tag molecules in a ratio of 95:5. LDI-TOF MS of these carboxylic acid-presenting AuNPs loaded with Am-tag or dAm-tag gave peaks at m/z 552.9 [M+Na] + and 560.9 [M+Na] + corresponding to the Am-tag or dAm-tag disulfides, respectively, and at m/z 699.0 [M+Na] + and 703.0 [M+Na] + corresponding to the carboxylic acid-containing disulfides, respectively (Figs.…”

Section: Characterization Of the Am-tag-coated Aunps And The Biochipsmentioning

confidence: 99%

Determining the Ratio of Two Types of Prostate Specific Antigens with Biochips and Gold Nanoparticles for Accurate Prostate Cancer Diagnosis

Yoo

Yeo

2016

ANAL. SCI.

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Prostate-specific antigen (PSA) is a well-known biomarker for prostate-cancer diagnosis. However, the serum PSA measurement alone is insufficient for accurate diagnoses because the correlation with cancer is weak within the gray zone-the biomarker level range wherein a clear-cut diagnosis is impossible. As such, accurate prostate cancer diagnosis has been supplemented by measurements of the ratio of two types of PSA: free PSA (fPSA) and complexed PSA (cPSA; α-1-antichymotrypsin-bound PSA). Herein, we describe a new method for measuring the ratio of these two types of PSA by using gold nanoparticles (AuNPs) and biochips. Both types of PSA in a sample are captured by the antibody immobilized on a biochip based on self-assembled monolayers on gold. fPSA and cPSA on the biochip are then distinguished by AuNPs that present antibodies against fPSA and cPSA, respectively. The presence of PSAs in a sample is detected with laser desorption/ionization time-of-flight mass spectrometry by observing reporter molecules, called amplification tags (Am-tags), on the AuNPs. One of the reporter molecules is an Am-tag without isotope labeling, and the other is a deuterium-labeled Am-tag (dAm-tag). These tags amplify mass signals so as to enhance the sensitivity of the method. A comparison of the mass intensities between the Am-tag and dAm-tag signals allows the determination of the ratio between fPSA and cPSA. We validated the selective measurement of fPSA and cPSA at different ratios in 50, 75, and 100 pM of total PSA (fPSA + cPSA) solutions corresponding to the gray zone in prostate-cancer diagnosis (4 - 10 ng/mL). Finally, the two types of PSA were spiked in fetal bovine serum at various ratios, and our strategy greatly afforded their accurate ratios as spiked based on a constructed calibration curve. These results clearly indicate that the strategy is applicable to human serum as a diagnostic and prognostic assay for prostate cancer.

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Analysis of alkanethiolates on gold with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Cited by 13 publications

References 70 publications

On-Demand Modulation of Bacterial Cell Fates on Multifunctional Dynamic Substrates

On-Demand Modulation of Bacterial Cell Fates on Multifunctional Dynamic Substrates

Tetrahydrofuran Highly Enhances SAMDI Efficiency

Determining the Ratio of Two Types of Prostate Specific Antigens with Biochips and Gold Nanoparticles for Accurate Prostate Cancer Diagnosis

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