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A stimuli-responsive nanogel-based sensitive and selective fluorescent sensor for Cr(3+) with thermo-induced tunable
Xuejuan Wan1, Haiyang Liu, Shen Yao
1College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China; Institute of Advanced Materials, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China; Key Laboratory for Advanced Materials of Ministry of Education, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
This study introduces a novel poly(N-isopropylacrylamide) nanogel as a fluorescent probe for detecting chromium ions (Cr3+). The nanogel exhibits enhanced sensitivity and tunable detection capabilities in response to temperature changes.
Area of Science:
- Materials Science
- Analytical Chemistry
- Nanotechnology
Background:
- Chromium ions (Cr3+) are significant environmental pollutants.
- Developing sensitive and selective detection methods for Cr3+ is crucial.
- Stimuli-responsive polymers offer tunable properties for sensing applications.
Purpose of the Study:
- To develop a poly(N-isopropylacrylamide) nanogel (P(NIPAM-co-RhBUA)) as a sensitive fluorescent probe for Cr3+.
- To investigate the thermo-induced tunable detection capacity of the nanogel for Cr3+.
- To explore the role of the nanogel's phase transition in enhancing detection performance.
Main Methods:
- Synthesis of stimuli-responsive poly(N-isopropylacrylamide) nanogel with covalently labeled rhodamine B urea derivatives (P(NIPAM-co-RhBUA)).
- Investigation of selective binding of the nanogel with Cr3+ at 20 °C, leading to fluorescence OFF-ON switching.
- Analysis of enhanced fluorescence intensity and detection sensitivity upon heating above the phase transition temperature (e.g., at 45 °C).
Main Results:
- The P(NIPAM-co-RhBUA) nanogel selectively binds Cr3+ over other metal ions at 20 °C, causing a fluorescence OFF-ON switch.
- Heating the nanogel above its phase transition temperature significantly enhances fluorescence intensity (≈61-fold increase at 45 °C) in the presence of Cr3+.
- Improved detection sensitivity for Cr3+ was observed with the collapsed nanogel, indicating the role of its hydrophobic microenvironment.
Conclusions:
- The developed P(NIPAM-co-RhBUA) nanogel is a promising fluorescent probe for sensitive and selective detection of Cr3+.
- The thermo-induced phase transition of the nanogel provides a tunable mechanism to enhance Cr3+ detection.
- The hydrophobic microenvironment within the collapsed nanogel is critical for its superior detection performance.
