Chandra A, Prasad S, Iuele H, Colella F, Rizzo R, D'Amone E, Gigli G, del Mercato LL. Highly Sensitive Fluorescent pH Microsensors Based on the Ratiometric Dye Pyranine Immobilized on Silica Microparticles.
Chemistry 2021;
27:13318-13324. [PMID:
34231936 PMCID:
PMC8518825 DOI:
10.1002/chem.202101568]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Indexed: 12/22/2022]
Abstract
Pyranine (HPTS) is a remarkably interesting pH-sensitive dye that has been used for plenty of applications. Its high quantum yield and extremely sensitive ratiometric fluorescence against pH change makes it a very favorable for pH-sensing applications and the development of pH nano-/microsensors. However, its strong negative charge and lack of easily modifiable functional groups makes it difficult to use with charged substrates such as silica. This study reports a methodology for noncovalent HPTS immobilization on silica microparticles that considers the retention of pH sensitivity as well as the long-term stability of the pH microsensors. The study emphasizes the importance of surface charge for governing the sensitivity of the immobilized HPTS dye molecules on silica microparticles. The importance of the immobilization methodology, which preserves the sensitivity and stability of the microsensors, is also assessed.
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