A technology developed by Mireille Blanchard-Desce & Jonathan Daniel (Plateforme NanoMultiPhot, Institut des Sciences Moléculaires de Bordeaux, France)
NanoTracers are a new class of fluorescent tracers obtained from the precipitation of organic dyes in water. Their unique physical and optical properties make them particularly well-suited for single-particle tracking experiments.
What makes them a top choice for single-particle tracking experiments?
Very low tendency to aggregate, thanks to their high intrinsic colloidal stability. This means they don't need any surface modification to prevent aggregation, a very practical feature when working with complex media.
Small size (14-17 nm diameter), to achieve finer spatial scales and temporal resolution even in the most crowded environments.
Excellent brightness & photostability, allowing for quick and reliable extraction of diffusion parameters.
Versatile use: naturally biocompatible, these organic nanoparticles come in different versions tailored for specific media (non-biological, intra/extra-cellular or live tissues).
Two types of NanoTracers to fit your desired application:
NanoTracer - Rheo kit
Due to their spontaneous stealth behavior, these nanoparticles do not require the use of antifouling agents to impede interactions with cellular membranes.
They can be used to assess properties of any type of biological or non-biological media (i.e. extra-cellular space).
With a diameter averaging that of an antibody and record brightness in 2-photon microscopy, they are perfectly compatible with deep tissue imaging for exploring the extra-cellular space of living tissues.
Key features:
- No interactions with living cells
- Red emission
- Compatible with 2-photon microscopy
- Median diameter: 17 nm
NanoTracer - Cell kit
These nanoparticles are naturally uptaken by live cells with no signs of toxicity or unspecific binding to cellular membranes.
They can be used for intracellular single-particle experiments to assess internal cell media properties or track intracellular transport dynamics.
With an ultra-high near-IR brightness and large Stokes' shift, they can be tracked at low laser intensities to best preserve cell physiology.
Key features:
- Natural intracellular uptake
- Bright near-IR emission with minimal laser intensity
- No cytotoxicity
- Median diameter: 15 nm
NanoTracer - Rheo kit
- Excitation max: 458 nm
Emission max: 591 nm
Brightness: 1.1 x 10^7 M-1.cm-1 (458nm) - Color: red
- Median diameter: 17 nm
- Concentration: 10^11 particles/mL
- Natural intracellular uptake: no
- Optical parameters under 2-photon excitation:
Excitation max : 840 nm
Cross-section: 1.8 x 10^6 GM
Brightness: 5.4 x 10^5 GM
NanoTracer - Cell kit
- Excitation max: 503 nm
Emission max: 724 nm
Brightness: 9.0 x 10^5 M-1.cm-1 (503 nm) - Color: near-IR
- Median diameter: 14 nm
- Concentration: 10^11 particles/mL
- Natural intracellular uptake: yes
NanoTracer - Rheo kit
Absorption (black line) and emission (red line) spectra of NanoTracer - Rheo kit in water
NanoTracer - Cell kit
Absorption (left) and emission (right) spectra of NanoTracer - Cell kit in water
Storage: NanoTracers can be stored for one year at 4°C, protected from light. Do not freeze.
Single-molecule photostability study of NanoTracers shows longtime single-particle tracking capacity
Source publication: Daniel J. et al, 2016
Single particle tracking of NanoTracers - Cell kit in live cells
Source publication: Daniel J. et al, 2016
Interplay between NanoTracers - Rheo kit and live cells
Representative 1P (left) and 2P (right) fluorescence images of bare (top) and PAH-coated (bottom) NanoTracers – Rheo kit incubated for 24h with Cos7 cells (1% v/v in cell culture medium) are provided. Maximal projections of z-stack images are displayed. Excitation wavelengths and emission detection ranges are indicated for each condition.
Source publication: Pagano P. et al, 2021
Single-particle tracking of NanoTracers in water
NanoTracers – Cell kit were imaged freely diffusing in water. The cumulative trajectories of the nanoparticles detected in each frame (left, in colored boxes) are shown on the right sub-panel using a corresponding color code. For each single nanoparticle tracked for more than four frames, its diffusion coefficient was extracted from its square displacements. Scale bars: 5 μm. A 488 nm laser power of 306 W·cm−2 was used for these experiments.
Source publication: Daniel et al, 2016