Latent pH-responsive ratiometric fluorescent cluster based on self-assembled photoactivated SNARF derivatives

Abstract

We have developed a self-assembled fluorescent cluster comprising a seminaphthorhodafluor (SNARF) derivative protected by a photoremovable o-nitrobenzyl group. Prior to UV irradiation, a colorless and nonfluorescent cluster was spontaneously assembled in aqueous solution. After UV irradiation, the self-assembled cluster remained intact and showed a large enhancement in pH-responsive fluorescence. The unique pH responsive fluorescent cluster could be used as a dual-emissive ratiometric fluorescent pH probe not only in the test tube but also in HeLa cell cultures.

Keywords:

• Self-assembly
• fluorescent material
• ratiometry
• pH indicator
• photoactivation

Classification:

• 30 Bio-inspired and biomedical materials
• 101 Self-assembly / Self-organized materials
• 208 Sensors and actuators

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary data

The supplementary material for this paper is available online at http://dx.doi.org/10.1080/14686996.2016.1204888

Notes

¹ To check the products after UV irradiation, HPLC profiles of SNARF-OBn(oNO₂) were obtained before or after UV irradiation (Figure S5). The main product was SNARF-OH, and two other peaks were observed, which may correspond to a reaction intermediate or a byproduct.

² The size of the self-assembled clusters at different pH values was also measured by DLS as shown in Table S1. The formation of the self-assembled clusters was confirmed in a wide pH range (from pH 4.0 to pH 10.0), in agreement with our previous report.[10]