Repository logo
 

Upconversion nanoparticles for sensing pH.

Accepted version
Peer-reviewed

Loading...
Thumbnail Image

Type

Article

Change log

Authors

Tsai, Evaline S 
Himmelstoß, Sandy F 
Wiesholler, Lisa M 
Hirsch, Thomas 
Hall, Elizabeth AH 

Abstract

Upconversion nanoparticles (UCNPs) can provide a vehicle for chemical imaging by coupling chemically sensitive dyes and quenchers. The mechanism for coupling of two anthraquinone dyes, Calcium Red and Alizarin Red S, was investigated as a function of pH. The green emission band of the UCNPs was quenched by a pH-dependent inner filter effect (IFE) while the red emission band remained unchanged and acted as the reference signal for ratiometric pH measurements. Contrary to previous expectation, there was little evidence for a resonance energy transfer (RET) mechanism even when the anthraquinones were attached onto the UCNPs through electrostatic attraction. Since the UCNPs are point emitters, only emitters close to the surface of the UCNP are within the expected Förster distance and UC-RET is <10%. The theoretical and experimental analysis of the interaction between UCNPs and pH-sensitive quenchers will allow the design of UCNP pH sensors for determination of pH via IFE.

Description

Keywords

34 Chemical Sciences, 3406 Physical Chemistry

Journal Title

Analyst

Conference Name

Journal ISSN

0003-2654
1364-5528

Volume Title

144

Publisher

Royal Society of Chemistry (RSC)

Rights

All rights reserved
Sponsorship
Engineering and Physical Sciences Research Council (EP/L015978/1)
This work was supported by the EPSRC Cambridge NanoDTC, EP/L015978/1