Dear Dr. Karen Carreon,

I suggest you to have a look at the following, interesting papers:

-Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

Stefanos Mourdikoudis, Roger M. Pallares and Nguyen T. K. Thanh

Nanoscale, Issue 27 (2018)

Available at: https://pubs.rsc.org/en/content/articlelanding/2018/nr/c8nr02278j#!divAbstract

-Measuring particle size distribution of nanoparticle enabled medicinal products, the joint view of EUNCL and NCI-NCL. A step by step approach combining orthogonal measurements with increasing complexity

Caputo F., Clogston J.,Calzolai L., Rösslein M., Prina-Mello A.

Journal of Controlled Release, Vol. 299, Pages 31-43 (2019)

Available at: https://www.sciencedirect.com/science/article/pii/S0168365919301130

-On the Operational Aspects of Measuring Nanoparticle Sizes

Jean-Marie Teulon, Christian Godon, Louis Chantalat, Christine Moriscot, Julien Cambedouzou, Michael Odorico, Johann Ravaux, Renaud Podor, Adèle Gerdil, Aurélie Habert, Nathalie Herlin-Boime, Shu-wen W. Chen, and Jean-Luc Pellequer

Nanomaterials, 9(1): 18 (2019)

Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6359205/

If you are interested in the surface morphology and you can detect nanoparticles with optical microscopy, you could use also an optical no-contact 3D profilometer. It is a non destructive and adaptive technique. It allows one to observe micro or nano surface details and quantify different roughness parameters. It is possible to obtain 3D topographic maps.

Best regards, Pierluigi Traverso

Dear Dr. Karen Carreon,

I suggest you to have a look at the following, interesting papers:

-Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

Stefanos Mourdikoudis, Roger M. Pallares and Nguyen T. K. Thanh

Nanoscale, Issue 27 (2018)

Available at: https://pubs.rsc.org/en/content/articlelanding/2018/nr/c8nr02278j#!divAbstract

-Measuring particle size distribution of nanoparticle enabled medicinal products, the joint view of EUNCL and NCI-NCL. A step by step approach combining orthogonal measurements with increasing complexity

Caputo F., Clogston J.,Calzolai L., Rösslein M., Prina-Mello A.

Journal of Controlled Release, Vol. 299, Pages 31-43 (2019)

Available at: https://www.sciencedirect.com/science/article/pii/S0168365919301130

-On the Operational Aspects of Measuring Nanoparticle Sizes

Jean-Marie Teulon, Christian Godon, Louis Chantalat, Christine Moriscot, Julien Cambedouzou, Michael Odorico, Johann Ravaux, Renaud Podor, Adèle Gerdil, Aurélie Habert, Nathalie Herlin-Boime, Shu-wen W. Chen, and Jean-Luc Pellequer

Nanomaterials, 9(1): 18 (2019)

Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6359205/

If you are interested in the surface morphology and you can detect nanoparticles with optical microscopy, you could use also an optical no-contact 3D profilometer. It is a non destructive and adaptive technique. It allows one to observe micro or nano surface details and quantify different roughness parameters. It is possible to obtain 3D topographic maps.

Best regards, Pierluigi Traverso

Dear Karen Carreon ,

You can try with several types of Scanning Probe Microscopy (SPM):

-With Atomic Force Microscopy (AFM), besides topographic features, if you use non-contact mode the phase can give you “chemical contrast” due to the different local energy dissipation when the tip is scanning a nanoparticle or a PLA region. -Moreover, if your particles are metallic or magnetic, you can use Electrostatic Force Microscopy (EFM) or Magnetic Force Microscopy (MFM), respectively, to distinguish them from the plastic even if they are buried.

Dear Karen,

There are so many ways the nano-particles can be counted. Single particle counting, aggregate nano-particle counting or just a wire piece counting instrument is available. Though finding another ways are still in progress to measure at molecular level.

Innovations in nanotechnology have brought tremendous opportunities for the advancement of many research frontiers, ranging from electronics, photonics, energy, to medicine. The nanoparticles are ultrafine particles in the size of nanometer order. “Nano” is a prefix denoting the minus ninth power of ten, namely one billionth. Here it means nanometer (nm) applied for the length. One nm is extremely small length corresponding to one billionth of 1 m, one millionth of 1 mm, or one thousandth of 1 μm.

I think simple and best way to be determined as;

(i) By dispersing the nanoparticles into a gas. If Nanoparticles (NPs) are spherical in shape ( he weight of gold taken for NPs synthesis (Au only, not gold salt) voulme can be calculated.

(ii) a number of analytical methods are currently under development. Some of the methods calculate concentrations based on ensemble physical properties of nanoparticle dispersions (e.g., light absorption)

(iii) Microscopy and sensors directly count individual particles

Though above all have measurement limitations on nanoparticle sizes and compositions. Another techiniques are quite fine with number of countings.

Advance techniques

(i) One method based on DLS (Dynamic light scattering (DLS)) uses photon count rate as an indicator of nanoparticle concentration. The photon count rate is defined as the number of photons detected per second by the DLS machine and has a unit of kilo counts per second (kCPS). At a certain concentration range, photon count rate is proportional to the scattered light intensity of colloidal dispersions.

I = BP, where I is the scattered light intensity, B is a constant and P is the photon count rate. Further, P1P2=d16d26C1C2 , where P1 and P2 are the photon count rate of standard and unknown samples respectively, C1 and C2 are the number concentrations, and d1 and d2 are the diameters of these two samples (d1, d2 need to fit Rayleigh scattering criteria).

(ii) Laser-induced breakdown detection (LIBD)

LIBD can detect colloids with very low concentrations, which may not be detectable by light scattering methods. Because of these excellent characteristics, LIBD has been widely used to characterize colloids in natural aquatic systems and detect impurities in ultrapure water.

(iii)Single Particle Counting (can be measured using equipment methodology Inductively Coupled Plasma Mass Spectrometry (ICPMS), Resistive-pulse sensing, Optical sensing, Tracking and imaging nanoparticles.

(iv)Scanning electron microscope,Transmission electron microscope and XRD analysis. TEM is best. To ensure unbiased estimation of nanoparticles in the entire cell population, each 200-nm section can be selected randomly from a sample pool and a fraction of each sample on the TEM grid is analyzed. By using a fractionation equation, the total number of nano-particles and the number of particles in a single cell or in sub-cellular organelles can be calculated.

Ashish

Great useful you are recommended, dear Professor Pierluigi Traverso

thak

Thank you so much to all of you !

I'll search for the techniques at my institute or institutes near by and discuss with my PI if that's what we are looking for.

Kind regards

Karen Carreon

'Amount' implies mass or volume. 'How many' implies number.

Why do you need the number of nanoparticles? It's a big number!

Would your materials be sold on the basis of number of particles? How much material could you characterize by, say, SEM?

What properties of your system are governed by number as opposed to, say, surface area or volume?

There's a chapter on characterization of nanomaterials in:

Chapter Characterization of Nanomaterials