Storage & Stability
Are Cellaris™ and Vascular Tracker™ stable at room temperature?
Yes, both Cellaris™ and Vascular Tracker™ are stable at room temperature for a couple of days. However, we strongly recommend storing all probes and solutions at 4°C.
Do not freeze our products.
What are the shipping conditions for Luminicell products?
All Luminicell products are delivered at ambient shipment condition.
Upon receiving the products, please store them under recommended storage conditions of 4°C.
Purchasing
What is the estimated delivery time for Luminicell products?
Delivery times may vary depending on your location. Generally, shipments are processed within 1-2 business days if the product is in stock, and delivery is typically completed within 1 week.
Do you provide sample kits before purchasing a full package?
Yes, we offer free samples for new application areas that need to be tested. For scopes that we already have confidence in, we can provide special discount rates for the trial vials.
Cellaris™ Cell Labelling Kit
Compatibility & Applications
Is Cellaris™ compatible with multi-photon or two-photon excitation imaging?
Yes, the dyes are optimized for use in multi-photon imaging. With their exceptional brightness, large cross-sectional area for two- and three-photon absorption, and excellent photostability, these probes offer a significant competitive edge. They are an ideal choice for Two-Photon and Multi-Photon Excitation Microscopy and are likely among the brightest probes available on the market.
Is Cellaris™ compatible with STORM imaging for live cells?
Under the intense light conditions typically used in STORM (Stochastic Optical Reconstruction Microscopy) imaging, phototoxic effects of the excitation light are often observed in live cells.
Techniques like SMLM (Single-Molecule Localization Microscopy), which require lower excitation power, may be better suited for live-cell imaging.
Can Cellaris™ be used in 3D cell culture models?
Yes, Cellaris™ is suitable for labeling cells in 3D culture systems, including organoids and spheroids.
Due to its great cellular retention and inherent high brightness and photostability, the probes are particularly suited for long-term cell tracking applications.
Please refer to our Application note for more information.
Can Cellaris™ be used in primary cell cultures?
Yes, Cellaris™ products can stain primary cells with low to minimal cytotoxicity. Validation in various experimental series can be found in Publication and Reference List.
Can Cellaris™ be used to label sub-cellular structures such as organelles?
No, Cellaris™ is designed as a cytosolic tracker for long-term live-cell staining, providing even labelling of the cytoplasmic matrix.
These probes do not bind to specific sub-cellular structures or label organelles such as the nucleus.
Can Cellaris™ be used to label cellular membranes?
No, Cellaris™ are cytosolic trackers developed for long-term live-cell staining by evenly labelling cytoplasmic matrix. The probes are efficiently taken up by cells due to their functionalized surface with cell-penetrating peptides.
Can Cellaris™ be used to label fixed cells?
Yes, cells can be labeled with Cellaris™ before fixation with PFA, ensuring optimal fluorescence retention.
Can the Cellaris™ cell labelling kit be used for single-cell tracking in real-time?
Yes, cells can be labeled with Cellaris™ before fixation with PFA, ensuring optimal fluorescence retention.
Can Cellaris™ be used for single-cell tracking in real-time?
Yes, Cellaris™ is suitable for real-time single-cell tracking, providing long-term, stable fluorescence with minimal photobleaching. Its high signal-to-noise ratio allows for precise monitoring of individual cells over extended periods.
Which organisms and tissues can be stained with Cellaris™?
Cellaris™ is nanoparticle engineered with cell-penetrating peptide on the surface, and thus it is able to stain a variety of cells.
The list below reports known working cell lines, tissues or organisms that can be stained with Cellaris™, extracted from selected publications.
- Homo sapiens : U2OS, fibroblasts, HeLa, HUVEC, MCF-10A, HCT-116, A549, erythrocytes.
- Mus musculus : C2C12, IA32, skeletal muscle, primary cardiomyocyte, primary oocyte.
- Rattus norvegicus : primary hyppocampal neurons, primary cortex neurons, NRK.
- Cercopithecus aethiops : COS-7.
- Mesocricetus auratus : BHK.
- Drosophila melanogaster : Notum epithelium, S2.
- Didelphis marsupialis : OK-cells.
- Carassius auratus (goldfish) : retina bipolar cells
- Danio rerio (zebrafish) : retina bipolar cells
Please note that above list shown is non-exhaustive. Any cell line, tissue or organism is not included in list, does not translate to limitation on product staining performance.
Can I use Cellaris™ for tracking cell migration in wound-healing assays?
Yes, Cellaris™ is well-suited for cell migration studies, including wound-healing assays. Its long-term fluorescence stability allows for continuous tracking of cell movement without signal loss.
Can labelled cells be co-cultured with other cell types without cross-contamination?
Yes, labelled cells can be co-cultured with other cell types without fluorescence transfer or cross-contamination, as Cellaris™ is designed to remain within the originally labelled cells.
Is this dye toxic to certain cell lines, such as stem cells or primary neurons?
Cellaris™ is designed to be non-toxic and biocompatible, making it suitable for most cell types, including stem cells and primary neurons.
Does the labelling work for bacterial or fungal cells, or only mammalian cells?
Cellaris™ is optimized for mammalian cells and has not been extensively tested for bacterial or fungal cells.
A customer report indicated low labelling efficiency with bacteria and successful labelling of fungal cells.
If you are working with non-mammalian cells, we recommend conducting a pilot experiment to assess compatibility.
Can Cellaris™ be injected into the lateral ventricles of an adult mouse to label the SVZ NSCs? What are the recommended concentrations?
We don’t have prior experience with this relevant application. Cellaris™ nanoparticles are not engineered for a specific target but are modified with cell-penetrating peptides; therefore, when injected into the lateral ventricle, Cellaris™ may label any adjacent cells.
If customer is interested in proceeding the trial, we would recommend starting with 1 μL of the stock solution.
Performance & Functionality
Are Cellaris™ dyes toxic to cells?
Cellaris™ dyes are designed to be minimally toxic for live-cell imaging. However, toxicity may vary based on dye concentration and cell type. Only if above a certain threshold concentration is used, Cellaris™ will then start to show some effect on cell proliferation.
However, due to the inherent brightness and photostability, the probes can be used at significantly lower working concentration than ones with cytotoxic effects on cells.
We recommend using working concentrations of 2 to 10 nM for labelling, which is in the order of multiple magnitudes lower than comparable live cell stains.
Does Cellaris™ suffer from Aggregation-Caused Quenching (ACQ)?
No, quite the opposite.
Our products work through a unique mechanism called Aggregation Induced Emission (AIE), where the dyes become fluorescence and enhanced in brightness once they are aggregated.
Both Cellaris and Vascular Tracker are "nano-aggregates" of AIE dyes encapsulated in lipid nanoparticles, ensuring biocompatibility and high stability.
Learn more about our Technology.
Are fluorescence characteristics induced by aggregation of molecules inside the cells?
No, both Cellaris and Vascular Tracker consist of lipid encapsulated organic dyes, which are already in their nanoaggregates form, kept within the core of nanoparticles.
Learn more about the dyes' functioning in our Technology section.
Are there any differences in biological function between different colour options?
No, as only the fluorescence dyes within the core of the lipid nanoparticle differs between various colour options.
The surface functionalisation which are responsible for cellular uptake, cytotoxicity or cell retention does not differ between various colours.
Does the fluorescence intensity of Cellaris™ fade over time?
Cellaris™ is designed for stable, long-term fluorescence lasting up to 10 cell generations in vitro and more than 21 days in vivo with the longest reported duration of up to 8 weeks.
Can Cellaris™ be used in long-term imaging experiments? Is there a risk of photobleaching with prolonged imaging?
Cellaris™ is highly photostable, with the longest reported continuous irradiation lasting up to 33 minutes (2000 seconds) without fluorescence loss. This makes it ideal for long-term imaging applications.
What is the cell uptake mechanism of Cellaris™?
Cell uptake mechanism of Cellaris™ could vary in different cell types. We have evidence of macropinocytosis and clathrin-mediated endocytosis in some tested cell types, including embryonic stem cells.
Where are the Cellaris™ nanoparticles located inside the cells?
Cellaris™ are taken up by cells mainly via endocytic and macropinocytic pathways and thus stay in endosome and pinosome. Partial nanoparticles will escape from the endosomes and stay in cytoplasm.
Does Cellaris™ fluorescence transfer to daughter cells after cell division?
Yes, depending on the dye concentration and cell division rate, fluorescence may be diluted across daughter cells with the longest reported up to 10 cell generations.
Why is the NIR-II signal weaker than NIR-I or visible-range fluorophores?
The excitation and emission wavelengths in the NIR-II range penetrate deeper into tissue due to lower light scattering and absorption.
However, this advantage comes at the cost of reduced signal intensity, as:
- Higher wavelengths have inherently lower photon energy.
- Most standard detectors are not optimized for capturing NIR-II signals, requiring specialized IR-sensitive detectors (>1000 nm).
- Excitation efficiency in the NIR-II range is lower than in shorter-wavelength fluorophores.
Despite this, NIR-II imaging remains invaluable for deep-tissue in vivo imaging, offering superior resolution in thick samples compared to visible and NIR-I fluorophores.
Experimental Considerations
What dyes are recommended for complementary nuclear staining?
Considering the spectral profile of Cellaris™ 540 (Green) and 670 (Red), DNA stains usable with a standard Cy3 filter set are recommended.
Do Cellaris™ dyes work with cell dissociation solutions?
Yes, all Cellaris™ dyes are compatible with Accutase and trypsin, allowing for effective cell detachment and dissociation.
Can Cellaris™ be used in combination with other fluorescent dyes?
Yes, Cellaris™ can be multiplexed with other dyes, but careful selection of excitation/emission filters is necessary to avoid spectral overlap.
What is the recommended cell staining concentration and duration?
2 nM (dilute 100 x from 200 nM stock solution) is recommended as a starting concentration. Listed below are some of the identified effective labelling conditions based on our users’ feedback.
- Phagocytic cells, e.g. macrophages (1 hour with 2 nM)
- Islet cells (1 hour with 5 nM)
- Cancer cells (2 hours with 2 nM)
- Stem cells (4 hours with 4 nM)
- Neurons (24 hours with 2 nM)
- Progenitor cells (24 hours with 4 nM)
Please refer to our Cellaris User Protocol for more details.
Can Cellaris be used in 3D in vitro models and what is the recommended work flow?
Yes. Cellaris is the best-in-class cell labelling probes in labelling and monitoring cells in 3D in vitro models, due to its ultra-high brightness, excellent photostability, and great biocompatibility.
Please refer to our Application note for information on fluorescence labelling and imaging of spheroids. There we have introduced the innovative bottom-up labelling approach with a simplified workflow, allowing for long-lasting uniform signal throught whole organoid, unveiling more possibilities to monitor cells and visualise cellular information deep within 3D structures.
Vascular Tracker™ Labelling Kit
Compatibility & Applications
Are there any protocol available that study vascular leakage?
Please find the protocol below:
Prepare Mice for Imaging
- Remove the hair on/around the area of the animal to be imaged to minimise absorption and scattering of light by the hair.
- For live animal skull bone marrow imaging, make a skin incision to expose the skull, then immobilise the head on the imaging stage.
Injection of Vascular Tracker
- Dilute 20–50 μL of the stock solution of Vascular Tracker with 1X PBS to a total volume of 100 μL for the injection solution (recommended dosage for mice weighing ~25 g). Note: For rats, the concentration of the labeling solution may be adjusted based on blood volume.
- Inject the Vascular Tracker solution intravenously via the lateral tail vein. The injection can be repeated daily if needed.
Imaging
- The live animal can be directly imaged after Vascular Tracker injection using two-photon microscopes and animal imaging systems. It is recommended to image live animals within 3 hours, as the signal will gradually decrease due to nanoparticle clearance during blood circulation.
- Organs can also be harvested post-injection, fixed, and cleared for further ex vivo imaging.
Is Vascular Tracker™ compatible with multi-photon excitation imaging?
Yes, the dyes are optimised for use in multi-photon imaging. With their exceptional brightness, large cross-sectional area for two- and three-photon absorption, and excellent photostability, these probes offer a significant competitive edge. They are an ideal choice for Two-Photon and Multi-Photon Excitation Microscopy and are likely among the brightest probes available on the market.
Can vascular leakage be quantified using Vascular Tracker™?
As the quantification of blood vessel leakage varies depending on imaging techniques and/or analysis methods, it may be difficult to provide a specific protocol.
You may refer to our Application Note 003 (Analysing Tumour-Associated Vessel Integrity in Zebrafish Using Vascular Tracker 670) for an approach to quantifying vascular leakage in a zebrafish model.
Additionally, a reference for leakage quantification in a micro-vessel-on-a-chip in vitro model can be found in Figure 2 of the following cited paper:
Hyaluronic Acid Turnover Controls the Severity of Cerebral Cavernous Malformations in Bioengineered Human Micro-Vessels, APL Bioeng. 8, 016108 (2024); doi: 10.1063/5.0159330.
Can Vascular Tracker™ penetrate the blood-brain barrier (BBB)?
Vascular Tracker™ is designed with an inert surface and a relatively large size (20–30 nm in diameter); therefore, it cannot pass through the BBB of healthy mice. However, in mice with brain diseases (e.g., brain tumors, neurological disorders, etc.), BBB permeability may be increased, allowing our nanoparticles (NPs) to penetrate.
Can Vascular Tracker™ cross the placenta? If injected into the mother, can I visualise vasculature in the embryos?
Vascular Tracker™ nanoparticles are designed with a PEGylated surface, which has been shown to be nearly impermeable to the placental barrier. Therefore, Vascular Tracker™ is considered to have limited ability to cross the placenta.
Do you have any in vivo (whole mouse) examples where Vascular Tracker™ was used, particularly in an IVIS system or something similar?
Since the IVIS system can only image in the visible-to-NIR-I region, it would not be ideal for whole mouse vasculature imaging. Live animal imaging systems with NIR-II region capability, however, can image the entire mouse vasculature due to deeper penetration, as well as reduced autofluorescence and scattering. Please find the Product brochure attached below for reference.
Does the Vascular Tracker™ work in Alzheimer’s disease or brain trauma models? If so, could you provide any references?
Vascular Tracker is designed to be inert and will flow inside the blood vessels without any specific targeting.
We currently do not have data available for Alzheimer’s or brain trauma models. However, customers are welcome to reach out to us at info@luminicell.com with detailed information (e.g., experimental purpose, procedure, etc.), so our technical team can provide better support for specific cases.
Have Vascular Tracker™ been tested for use in arthropods as well?
Vascular Tracker™ has not been tested in arthropods. However, customers are encouraged to try it if they are interested.
Can Vascular Tracker™ be used in insects?
Vascular Tracker™ has not been tested in insects. However, customers are encouraged to try it if they are interested.
The lab's primary focus is vascular damage, as they are working with hemorrhagic fever viruses. Can diffusion out of the vascular bed only be measured post mortem, or can it also be done in vivo? If so, how is it done?
To study vascular integrity, one of our collaborators used a vascular transgenic zebrafish model (in which blood vessel walls are transgenically labelled).
In this model, the Vascular Tracker™ signal observed outside the blood vessel walls is measured as vascular leakage. You may refer to our Application Note 003 (AnalyzingTumor-Associated Vessel Integrity in Zebrafish Using Vascular Tracker 670) for more details.
Performance & Functionality
Are Vascular Tracker™ dyes toxic to cells?
The Vascular Tracker™ dyes are designed to be inert and non-toxic under standard experimental conditions when used at recommended concentrations.
However, as with any experimental reagent, it is important to follow proper handling and dosing guidelines to minimize any potential effects.
Does Vascular Tracker™ suffer from Aggregation-Caused Quenching (ACQ)?
No, quite the opposite.
Our products work through a unique mechanism called Aggregation Induced Emission (AIE), where the dyes become fluorescence and enhanced in brightness once they are aggregated.
Both Cellaris and Vascular Tracker are "nano-aggregates" of AIE dyes encapsulated in lipid nanoparticles, ensuring biocompatibility and high stability.
Learn more about our Technology.
Are fluorescence characteristics induced by aggregation of molecules inside the cells?
No, both Cellaris™ and Vascular Tracker™ consist of lipid encapsulated organic dyes, which are already in their nano aggregates form, kept within the core of nanoparticles.
Learn more about the dyes' functioning in our Technology section.
Are there any differences in biological function between different colour options?
No, as only the fluorescence dyes within the core of the lipid nanoparticle differs between various colour options.
Can Vascular tracker™ be used in long-term imaging experiments? Is there a risk of photobleaching with prolonged imaging?
Yes, Vascular tracker™ is highly photostable, with the longest reported continuous irradiation lasting up to 33 minutes (2000 seconds) without fluorescence loss. This makes it ideal for long-term imaging applications.
Will the Vascular Tracker ™ signal be well retained in harvested organs, and can it be fixed and sectioned for inspection under a fluorescence microscope?
According to customer feedback, the Vascular Tracker ™ signal is well retained after organ fixation through either fixation agent immersion or cryopreservation. However, the current version of Vascular Tracker ™ may not be compatible with formaldehyde perfusion.
Additionally, we are developing the next generation of Vascular Tracker ™ products, which will be highly compatible with formaldehyde perfusion.
We invite you to follow us on our social media channels to stay updated on our new product releases.
What is the excretion pathway for the Vascular Tracker™ nanoparticles? Will they ultimately be absorbed by phagocytic cells?
Vascular Tracker™ nanoparticles will accumulate in the liver and spleen and will be excreted from the body via the biliary pathway.
Why is the NIR-II signal weaker than NIR-I or visible-range fluorophores?
The excitation and emission wavelengths in the NIR-II range penetrate deeper into tissue due to lower light scattering and absorption. However, this advantage comes at the cost of reduced signal intensity, as:
- Higher wavelengths have inherently lower photon energy.
- Most standard detectors are not optimized for capturing NIR-II signals, requiring specialized IR-sensitive detectors (>1000 nm).
- Excitation efficiency in the NIR-II range is lower than in shorter-wavelength fluorophores.
Despite this, NIR-II imaging remains invaluable for deep-tissue in vivo imaging, offering superior resolution in thick samples compared to visible and NIR-I fluorophores.
Experimental Considerations
In mammalian species, what is the half-life of Vascular Trackers ™ in the bloodstream?
Based on a previous trial in a mouse model, the distribution half-life of Vascular Tracker ™ nanoparticles is 0.6 hours, while the elimination half-life is 11.7 hours.
Can Vascular Tracker™ be used in combination with other fluorescent dyes?
Yes, Vascular Tracker™can be multiplexed with other dyes, but careful selectionof excitation/emission filters is necessary to avoid spectral overlap.
What are the concentration ranges that have been previously injected into adult mice?
The proven concentration range, based on customer feedback, is 40–200 nM. The injection volume is typically 4 μL per gram of mouse body weight.
Based on the manual, fluorescence can be detected immediately after injection and up to 3 hours in animal models. Could it be sustained for a longer period in the case of organ fixation following Vascular Tracker ™ injection?
Imaging within 3 hours is recommended for vessel imaging in live animals, as the nanoparticles are gradually cleared during circulation. However, in terms of photostability, our nanoparticles are best-in-class fluorescent probes. Please refer to Application note for reference—although conducted on Cellaris ™ (cell tracker), the same dye structures are used in Vascular Tracker ™, ensuring similar stability.
Therefore, if the organ is fixed after Vascular Tracker injection, the fluorescence signal can be sustained for a longer period.
The lab has previously used mCherry (and GFP to some extent) for in vivo imaging but encountered significant autofluorescence interference. Bioluminescence provided better results. What wavelength would you suggest to minimise autofluorescence in the red channel?
To reduce background signal, we recommend using a longer wavelength (red-shifted) channel. A brighter signal from Vascular Tracker ™ can also improve the signal-to-noise ratio.
For imaging in the visible-to-NIR-I range, we suggest:
- Vascular Tracker 810 ™ (Excitation: 633 nm, Detection: 750–900 nm)
- Vascular Tracker 670 ™ (Excitation: 488 nm, Detection: 700–800 nm)
If NIR-II detectors are available, we highly recommend Vascular Tracker ™ 1010 (Excitation: 755/808 nm, Detection: >1000 nm), as the NIR-II channel provides a clean signal with no autofluorescence interference.
How long should Vascular Tracker ™ be allowed to circulate before harvesting to evaluate leakage?
Based on our previous experience,1–3 hours of circulation after intravenous injection is ideal for organ harvesting and leakage evaluation.
Chemical Composition & Handling
Does Vascular Tracker™ contain any organic solvents, such as DMSO?
We do not use nor introduce any amount of DMSO into the products throughout the manufacturing processes.
Any other organic solvents are removed during the processes.
Are there any hazardous components in Vascular Tracker™ dyes?
Vascular Tracker™ dyes are designed to be non-toxic and safe for standard lab use. However, always refer to the Safety Data Sheet (SDS) for more information.
Does Vascular Tracker ™ label the cells in the vessel or the blood?
Vascular Tracker ™ is designed to remain within the bloodstream, labelling the circulating blood rather than the vessel walls or endothelial cells. It is designed not to bind to cells within the vessel but can be used to visualise blood flow and vascular integrity.
What is the diameter of Vascular Tracker™ nanoparticles?
Vascular Tracker™ nanoparticles have a diameter of 20–30 nm.
What is the structure of the Vascular Tracker™ nanoparticles?
Vascular Tracker™ nanoparticles consist of two layers:
- A hydrophobic dye core
- An outer PEGylated lipid layer, encapsulated using patented technology
This structure enhances biocompatibility, stability, and circulation time in biological systems.