Dimerization of Organic Dyes on Luminescent Gold Nanoparticles for Ratiometric pH Sensing. Issue 7 (8th January 2016)

• Record Type: Journal Article
• Authors: Sun, Shasha; Ning, Xuhui; Zhang, Greg; Wang, Yen‐Chung; Peng, Chuanqi; Zheng, Jie
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 7(2016)
• Page Start: 2421
• Page End: 2424
• Publication Date: 2016-01-08
• Subjects: dimerization -- dyes -- gold nanoparticles -- luminescence -- pH sensors; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201509515
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Synergistic effects arising from the conjugation of organic dyes onto non‐luminescent metal nanoparticles (NPs) have greatly broadened their applications in both imaging and sensing. Herein, we report that conjugation of a well‐known pH‐insensitive dye, tetramethyl‐rhodamine (TAMRA), to pH‐insensitive luminescent gold nanoparticles (AuNPs) can lead to an ultrasmall nanoindicator that can fluorescently report local pH in a ratiometric way. Such synergy originated from the dimerization of TAMRA on AuNPs, of which geometry was very sensitive to surface charges of the AuNPs and can be reversely modulated through protonation of surrounding glutathione ligands. Not limited to pH‐insensitive dyes, this pH‐dependent dimerization can also enhance the pH sensitivity of fluorescein, a well‐known pH‐sensitive dye, within a larger pH range, opening up a new pathway to design ultrasmall fluorescent ratiometric nanoindicators with tunable wavelengths and pH response ranges. Abstract : More than its parts : Dimerization of pH‐insensitive fluorophores on ultrasmall luminescent gold nanoparticles creates a highly sensitive ratiometric probe of local pH. This conjugation process can also extend the range of pH‐sensitive dyes, allowing for tunable sensing features.