Frequently Asked Questions

General Questions

What are nanodiamonds?

Nanodiamonds are extremely small diamonds, with a size below 1 micrometer (1um).  Like all diamonds, nanodiamonds are made up almost entirely of carbon but can contain a very small amount of non-carbon contaminants which can impart color, electrical conductivity, fluorescence, magnetic sensitivity, and other properties.

There are many different types of fluorescent nanodiamonds, but the best studied is the Nitrogen-Vacancy diamond, or NV-center diamond.  NV-centers are atomic defects within the crystal structure of diamond and are comprised of a nitrogen atom (N) adjacent to a vacant or empty site (V).  Cymaris Labs has created NV-centers in both microdiamonds as well as in nanodiamonds.  Excitation of an NV-center with green (532 nm) light results in broadband photoluminescence (~575 nm to 650 nm) that extends into the near-infrared region.  Nanodiamonds containing NV-centers display extreme chemical stability as well as photostability and exhibit long spin coherence times (~25 ns). 

What are the advantages of fluorescent nanodiamonds compared to other fluorescent probes?

One clear advantage of nanodiamonds over other fluors is their extreme photostability, meaning that their fluorescence does not fade, even under extensive excitation with green light.  This permits users to repeatedly interrogate NV-center fluorescence, without worrying about photobleaching.

What are the other properties of nanodiamonds that can be advantageous?

In addition to near perfect photostability, other potentially advantageous properties of fluorescent NV-center nanodiamonds (FNDs) include superior chemical reactivity, biocompatibility, high thermal conductivity and electrical resistivity, chemical and heat stability, and tolerance to extremes in pH, pressure, and radiation, and harsh chemicals.


Can nanodiamonds be used in bio-imaging and medical diagnostics?

FND-immunoconjugates (having several antibody molecules conjugated to the FND) can be used for drug delivery, in vitro cell labeling, in vivo imaging in small animals, detecting cellular biomarkers, and as probes for other biomedical applications.  These Cymaris products are for research use only (RUO). 

Are FNDs suitable for nanomedicine?

Studies of carbon nanomaterials for biological applications have revealed that nanodiamonds are much more biocompatible than most other carbon nanomaterials, including carbon blacks, fullerenes, and carbon nanotubes.  The noncytotoxic nature of nanodiamonds, together with their unique stable photoluminescence, tiny size, large specific surface area, and ease with which they can be functionalized with biomolecules, makes nanodiamonds attractive to researchers for various biomedical applications both in vitro and in vivo.  Cymaris products are for research use only.


Are nanodiamonds commercially applicable?

Nanodiamond is a useful material for biological and medical research, owing to its relatively inexpensive and large-scale synthesis, unique structure, and superior optical properties.  Due to its non-blinking, non-quenching NIR emission, it is also an ideal fluorescence standard, (fiducial marker).  However, most biomedical applications, such as drug delivery and bio-imaging, are still under development.  These applications are dependent upon the precise control of the surfaces, and can be significantly affected by the type, distribution, and stability of chemical functionalization of the nanodiamond surface.


Are nanodiamonds degradable?

Nanodiamonds can burn at approximately 763 (1405°F ) in the presence of oxygen but are stable below this temperature.  And their structure and fluorescence are not degraded by extreme pH, pressure, radiation, or chemical conditions.  


How are Cymaris nanodiamonds produced?

Nanodiamonds can be produced by several methods, including 

  • Formation in nature –This process, and therefore the properties of the nanodiamonds formed by it, are not controllable.
  • Chemical vapor deposition (CVD)  – This is a highly controlled process that produces diamond with precise characteristics.
  • High pressure-high temperature (HPHT) methods – Cymaris diamonds are created by the HPHT process, which is also a controlled process.  Both CVD and HPHT diamonds are more easily cleaned than detonation diamonds, and their surfaces can be functionalized for scientific, medical, and other purposes.  

Application Questions

In what way can the quantum sensing abilities of nanodiamonds can be used?

The quantum sensing abilities of nanodiamonds can be used to improve the sensitivity of paper-based diagnostic tests, potentially allowing for earlier detection of diseases such as HIV and cancer.  New research indicates that low-cost nanodiamonds could be used to signal the presence of an HIV disease marker with a sensitivity many thousands of times greater than the gold nanoparticles widely used in these tests.  This greater sensitivity allows lower viral loads to be detected, meaning the test could pick up lower levels of disease or detect the disease at an earlier stage, which is crucial for reducing transmission risk of infected individuals and for effective treatment of diseases such as HIV.


Are Nanodiamonds as effective as organic fluors?

Most organic fluors experience fluorescent intermittency (‘blinking’), short fluorescent lifetime (fading), and/or small Stokes shift (difference between the maximum excitation and maximum emission wavelengths).  Nanodiamonds have a large Stokes shift and do not fade or blink.


What type of functionalization is possible?

Cymaris can functionalize nanodiamonds with hydroxyls, carboxyls, amines, thiol, propargyl, NHS, maleimide, biotin, streptavidin, and antibodies.  Most of these are provided with a polyethylene glycol PEG) linker to improve availability of the functional group.  Custom conjugations are also available.


What size is most suitable for diagnostics and drug delivery?

Depending upon specifics of the application, nanodiamonds should be approximately 50-100 nm for use in diagnostics and drug delivery.


What is the difference between NV and NVN?

Structural:  An NV nanodiamond contains vacancies, or holes in the crystal structure, situated adjacent to a nitrogen atom that has replaced a carbon in the crystal.  An NVN contains vacancies situated adjacent to two nitrogen atoms.  

Fluorescence: The peak excitation/emission wavelengths for NV diamond are 532/637 nm.  The peak excitation/emission wavelengths for NVN diamond are xx/yy nm.

Are nanodiamonds easily dispersible?

Bare nanodiamonds tend to form aggregates that are difficult to disperse.  However, Cymaris nanodiamonds are cleaned, coated, and dispersed in an aqueous buffer appropriate for the functional groups on their surfaces.  If they settle out, they are easily resuspended by sonication.


What kind of applications can Nanodiamonds be used for?

Currently, we recommend the use of Cymaris nanodiamonds for flow cytometry and western blotting applications.  They can also be used for several other biomedical, experimental, and imaging applications.


Are nanodiamonds easily available in the US for commercial applications?

Yes, all Cymaris nanodiamond products are available in the US for commercial applications.


What is the fluorescence detection range for nanodiamonds?

The detection range depends upon the color center of the diamond.  NV diamonds are detected between 637 and 800 nm, and NVN diamonds are detected between 475 and 600 nm.


Can you generate red, green, and blue diamonds?

Yes, Cymaris can generate all three of these diamond types, and others as well.  However, until the other color center diamonds have been optimized for brightness, we recommend the use of only red (NV-center).  We do offer green (NVN-center) diamonds, but with the caveat that these are still under development and are not yet very bright.  


Are functionalized nanodiamonds sensitive to light and heat? 

The nanodiamonds and their fluorescence will not degrade with light or heat, but the functional groups on their surface will have the same heat and light sensitivities that they would under any other conditions.


Cymaris Products


What type of functional groups are possible?

Cymaris currently offers functionalized nanodiamonds with hydroxyls, carboxyls, amines, thiol, propargyl, NHS, maleimide, biotin, streptavidin, and antibodies.  Most of these are provided with a polyethylene glycol PEG) linker to improve availability of the functional group.  Custom conjugations are also available.

Why does the size of the FND matter?

A larger diamond provides a more intense, brighter signal.  However, depending upon the application, a smaller diamond may be required.


What is the best way to prep the nanodiamonds?

The nanodiamonds should be used as a suspension.  If the nanodiamonds have settled to the bottom of the tube, they should be resuspended by pipetting up and down with gentle sonication.


Is there a prescribed procedure to replace an organic fluor with nanodiamonds in an assay?

The nanodiamonds can be directly substituted for other fluors using the same preparation protocols recommended for the assay.  If the nanodiamonds have settled to the bottom of the tube, they should be resuspended by pipetting up and down with gentle sonication.


What are the recommended storage conditions for the nanodiamonds?

The nanodiamonds should be stored as a suspension in their original packaging. Storage temperatures are dependent upon the surface functional groups.  This will be provided in the instructions included with each product, and can also be found on the Cymaris website,