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A two-photon fluorescence, carbonized polymer dot (CPD)-based, wide range pH nanosensor: a view from the surface
Zepeng Huo1, Gang Chen, Yijia Geng
1State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China. xusp@jlu.edu.cn.
Nanoscale
|April 15, 2020
Summary
A novel green-emitting carbonized polymer dot (CPD) acts as a sensitive, low-toxicity pH indicator. This material enables multi-mode pH sensing and intracellular imaging, advancing carbon-based sensor development.
Area of Science:
- Materials Science
- Nanotechnology
- Analytical Chemistry
Background:
- Carbon nanodots (CDs) are emerging as versatile fluorescent nanomaterials.
- Developing sensitive and low-toxicity pH sensors is crucial for biological applications.
- Existing carbon nanodot pH sensors have limitations in response range and imaging capabilities.
Purpose of the Study:
- To synthesize a novel carbonized polymer dot (CPD) with high fluorescence quantum yield for pH sensing.
- To investigate the multi-mode pH sensing capabilities of the CPD using absorption, single-photon, and two-photon fluorescence (TPF).
- To elucidate the pH sensing mechanism and explore its potential for intracellular pH monitoring.
Main Methods:
- Hydrothermal synthesis of green-emitting CPDs.
- Characterization of CPD properties, including fluorescence quantum yield and stability.
- Transient spectroscopy to evidence the pH sensing mechanism.
- Application as a three-mode pH indicator (absorption, single-photon fluorescence, TPF).
- Intracellular pH sensing using TPF imaging.
Main Results:
- A high fluorescence quantum yield, low-toxicity green-emitting CPD was successfully synthesized.
- The CPD demonstrated three-mode pH sensing based on absorption, single-photon, and TPF signals.
- Transient spectroscopy confirmed that surface state hydrogen ion regulation governs the pH sensing mechanism.
- The CPD exhibited a wider pH-responsive range compared to other carbon nanodot sensors due to rich surface states.
- The CPD showed excellent brightness, stability, and low cell toxicity, suitable for intracellular pH sensing via TPF imaging.
Conclusions:
- The developed CPD is a promising material for advanced pH sensing applications.
- The study provides new insights into designing carbon-based sensing materials by controlling surface states.
- The CPD offers a novel candidate for up-conversion photoluminescence-responsive imaging agents with potential in cell diagnosis and dynamic pH monitoring.
