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High-Contrast Visualization of Upconversion Luminescence in Mice Using Time-Gating Approach
Xianlin Zheng1, Xingjun Zhu2, Yiqing Lu1
1Advanced Cytometry Laboratories, ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), Macquarie University , Sydney, New South Wales 2109, Australia.
Analytical Chemistry
|February 27, 2016
Summary
Time-gating with pulsed lasers significantly improves optical imaging sensitivity for upconversion nanoparticles (UCNPs) in small animals. This method enhances detection by over tenfold and reduces harmful thermal effects for safer in vivo bioimaging.
Area of Science:
- Biomedical Optics
- Nanotechnology
- In Vivo Imaging
Background:
- Near-infrared (NIR) optical imaging offers deep tissue penetration for biological studies.
- Upconversion nanoparticles (UCNPs) are promising NIR contrast agents for bioimaging.
- Current UCNP imaging requires high-power lasers, causing scattering and thermal issues.
Purpose of the Study:
- To enhance detection sensitivity and reduce thermal effects in UCNP-based in vivo bioimaging.
- To develop a practical and cost-effective solution for NIR animal imaging.
Main Methods:
- Implemented a time-gating technique using pulsed NIR diode laser illumination.
- Synchronized time-delayed imaging with an optical chopper.
- Utilized a setup including an optical chopper, pinhole, and microscopy eyepiece.
Main Results:
- Achieved over a 10-fold increase in detection sensitivity compared to conventional band-pass filter methods (S/N ratio improvement).
- Reduced thermal accumulation to 35% compared to continuous-wave laser illumination.
- Demonstrated successful imaging in Kunming mice injected with UCNPs.
Conclusions:
- Time-gating provides a convenient, low-cost method for sensitive NIR animal imaging.
- This approach is compatible with various cameras and luminescent probes.
- Significantly improves safety and efficacy of UCNP-based bioimaging.
