1,2,4-Triaminobenzene as a Fluorescent Probe for Intracellular pH Imaging and Point-of-Care Ammonia Sensing

Abstract

As one of the health indicators, intracellular pH plays important roles in many processes of cell functions. Abnormal pH changes would result in the occurrence of inflammation, cancer, and other diseases. Thus, it is of significant importance to develop effective techniques for sensitive detection of pH changes for the clinical diagnosis of various diseases related to cells. In this paper, 1,2,4-triaminobenzene hydrochloride was explored as an organic molecular fluorescent probe for sensitive and selective detection of intracellular pH changes for the first time. Due to the protonation and deprotonation of amino groups of the probe, its fluorescent intensity at 599 nm or the ratio of absorbance at 505 and 442 nm has a good linear relationship with pH values in the range of 5.0−7.0. Benefiting from the excellent physical and chemical properties of 1,2,4-triaminobenzene hydrochloride, the fluorescent probe has good water solubility, low toxicity, high photostability, great reversibility, good cell penetration, fast response speed, and so on. As a proof-of-concept demonstration, the proposed probe is employed for the fluorescence imaging of cells and mouse tissue sections with satisfactory performance in pH differentiation. Additionally, the probe was successfully employed to prepare test strips as a kind of point-of-care testing device to detect ammonia, which showed great potential in practical applications.

Portable Smartphone Platform Based on Aggregation-Induced Enhanced Emission Carbon Dots for Ratiometric Quantitative Sensing of Fluoride Ions

“…19,20 Nevertheless, most fluorescence sensing strategies employ a single fluorescence signal and are susceptible to environmental factors. 21,22 Furthermore, singlecolor fluorescent probes' narrow color range causes insignificant variations in fluorescent color, which hinders their resolution and application in visual analysis with the naked eye.…”

“…Recently, the intensive and integrated detection strategies based on smartphone devices have been shining brightly, allowing for intelligent reading and quantification of specific targets and on-site analysis. − That is, quantification is achieved by utilizing the specific relationship between the red–green–blue (RGB) values of the image and the concentration of the target. Among them, fluorescence is favored due to its rich color, stability, and ease of identification. , Nevertheless, most fluorescence sensing strategies employ a single fluorescence signal and are susceptible to environmental factors. , Furthermore, single-color fluorescent probes’ narrow color range causes insignificant variations in fluorescent color, which hinders their resolution and application in visual analysis with the naked eye. In contrast, ratiometric fluorescence strategies have been favored in recent years.…”