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Temperature sensing and bio-imaging applications based on polyethylenimine/CaF2 nanoparticles with upconversion
Guofeng Liu1, Zhen Sun1, Zuoling Fu1
1Coherent Light and Atomic and Molecular Spectroscopy Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, China.
Talanta
|April 17, 2017
Summary
Polyethylenimine-coated upconversion nanoparticles (UCNPs) offer efficient nano-thermometry and bio-imaging. These biocompatible nanoparticles exhibit bright green luminescence and high temperature sensitivity for biological applications.
Area of Science:
- Materials Science
- Nanotechnology
- Biomedical Engineering
Background:
- Rare earth ion-doped upconversion nanoparticles (UCNPs) are crucial for advanced applications like nano-thermometry and bio-imaging.
- Developing water-soluble and biocompatible UCNPs is essential for in vivo applications.
- Polyethylenimine (PEI) coating enhances nanoparticle properties for biological integration.
Purpose of the Study:
- To synthesize polyethylenimine (PEI) coated CaF2:Er3+,Yb3+ upconversion nanoparticles (UCNPs) using a one-pot solvothermal method.
- To characterize the synthesized UCNPs for their physical, optical, and thermal sensing properties.
- To evaluate the potential of these UCNPs for bio-imaging and nano-thermometry in biological systems.
Main Methods:
- One-pot solvothermal synthesis of PEI-coated CaF2: 1%Er3+, 2%Yb3+ UCNPs.
- Characterization of nanoparticle size, shape, and luminescence properties under 980nm excitation.
- Temperature sensing using the fluorescence intensity ratio (FIR) technique within the biological temperature range.
- In vitro bio-imaging of Hela cancer cells incubated with the synthesized UCNPs.
Main Results:
- Spherical UCNPs with an average size of 40nm were successfully synthesized, exhibiting good water-solubility and biocompatibility.
- Intense green luminescence was observed from Er3+ and Yb3+ co-doped nanoparticles under 980nm excitation.
- A maximum temperature sensitivity of 0.00215 K-1 was achieved in the biological temperature range using FIR.
- Visible green fluorescence from Er3+ was detected in Hela cancer cells after 6h incubation, indicating successful cellular uptake.
Conclusions:
- PEI-coated CaF2:Er3+,Yb3+ UCNPs are promising candidates for highly sensitive nano-thermometry.
- The synthesized UCNPs demonstrate excellent potential for bio-imaging applications due to their luminescence and biocompatibility.
- This study highlights the feasibility of using these UCNPs for theranostic applications in biological systems.