Issue 18, 2020

Discrimination of cysteamine from mercapto amino acids through isoelectric point-mediated surface ligand exchange of β-cyclodextrin-modified gold nanoparticles

Abstract

The discrimination of cysteamine (CA) from mercapto amino acids (including glutathione, cysteine and homocysteine, GSH/Cys/Hcy) with high efficiency is essential to detect biothiols in a physiological environment. Herein, a nano-assembly was constructed by combining one-pot synthesized β-cyclodextrin-modified AuNPs and encapsulated rhodamine 6G (R6G-β-CD@AuNPs) without covalent modification. Interestingly, when the pH value of the tested solution was approximately the isoelectric point (pI) of the biothiol, the quenched fluorescence of R6G-β-CD@AuNPs was obviously restored by the introduction of the biothiol, which was due to the replacement of the R6G-β-CD composite by the biothiol on the surfaces of AuNPs via a stronger S–Au bond. The pI-mediated surface ligand exchange process was designed for the first time for the discrimination and detection of CA and GSH/Cys/Hcy at the pH values of 9.5 and 5.5, respectively. Under the optimized conditions, the enhanced fluorescence intensity displayed a good linear response to the concentration of each biothiol, with the detection limits of CA, GSH, Cys and Hcy calculated as 66.8, 417.6, 652.7 and 603.4 nM, respectively. The ingenious fabrication of the R6G-β-CD@AuNPs sensing platform eliminated the interferences from cholesterol by host–guest interactions and enabled high selectivity for the detection of biothiols in human serum samples. The pI-mediated sensing platform exhibits great potential for biothiol-related therapeutic drug monitoring.

Graphical abstract: Discrimination of cysteamine from mercapto amino acids through isoelectric point-mediated surface ligand exchange of β-cyclodextrin-modified gold nanoparticles

Supplementary files

Article information

Article type
Paper
Submitted
19 Feb 2020
Accepted
20 Apr 2020
First published
21 Apr 2020

J. Mater. Chem. B, 2020,8, 4039-4045

Discrimination of cysteamine from mercapto amino acids through isoelectric point-mediated surface ligand exchange of β-cyclodextrin-modified gold nanoparticles

Q. Ma, X. Fang, J. Zhang, L. Zhu, X. Rao, Q. Lu, Z. Sun, H. Yu and Q. Zhang, J. Mater. Chem. B, 2020, 8, 4039 DOI: 10.1039/D0TB00462F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements