Construction and pH Response of Functionalized Quantum Dot Fluorescent Probes with Dopamine Quinone

doi:10.15541/jim20250169

Abstract

Abstract: Quantum dots have demonstrated significant potential in the field of biological detection due to their excellent photoluminescence properties. As one of the key parameters in regulating physiological functions, pH response with high sensitivity is of great significance. However, conventional pH fluorescent probes are frequently limited by insufficient sensitivity or poor stability. In this work, band gap engineering was used to optimize the design and construct a CdSe/CdS/ZnS core-shell structured quantum dot to improve the fluorescence quantum yield and stability. Additionally, the modification with mercaptoethylamine (MEA) and dopamine-isothiocyanate (DA-ITC) result in the development of a quantum dot fluorescent probe exhibiting a highly sensitive pH response. Experimental results indicate that the amino-protected CdSe/CdS/ZnS quantum dots possess excellent optical properties. Following modification with DA-ITC, the probe exhibits highly sensitive pH response performance. The underlying response mechanism is attributed to the fluorescence quenching effect of the dopamine quinone (DQ), which is formed by oxidation in the surface ligands under alkaline conditions on the quantum dots. For 1 nmol quantum dots, when the input amount of DA-ITC is within the range of 4 to 40 μg/nmol, the fluorescence intensity of the probe reveals a linear decrease trend with increasing pH ranging from 5.0 to 10.0 (R²>90%). Notably, when the addition of DA-ITC is set at 20 μg/nmol, the probe demonstrates optimal pH responsiveness(R²=0.9869). Moreover, this probe has good cell compatibility, allowing for effectively application in fluorescence imaging for monitoring of cell pH.

Key words: quantum dots, core-shell structure, pH response, redox

CLC Number:

O649

WANG Zheng, HOU XiaoQi, LIU XuanYong. Construction and pH Response of Functionalized Quantum Dot Fluorescent Probes with Dopamine Quinone[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20250169.

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