Accurate particle size distributions with better TEM images by using Bovine Serum Albumin (BSA).


I know what I am doing, take me directly to the

 What is BSA@AMI

A short explanation

BSA@AMI is a simple protocol that allows for accurate determination of size distributions of nanoparticles. This tool guides you step-by-step through the process of preparing your sample for transmission electron microscopy (TEM) to get an image that can be analyzed manually of with an image analysis software like Fiji or ImageJ

All you need is your sample:

  • a rough idea of the particle diameter
  • the particle mass density
  • Bovine Serum Albumin (BSA)

If you want to process your TEM images automatically, you could use ImageJ or Fiji.

If you are interested in the scientific details, you can read our paper.


This characterization method is applicable for a large variety of nanoparticles, however there are nanoparticle systems where the method is limited. For example, multicomponent systems, or in general systems that are difficult to disperse in water, can render the method impossible to infeasible. However, we are currently working on a protocol to apply the method to more complex particle systems for TEM image analysis. If you have any questions concerning your specific nanoparticle system, please do not hesitate to contact us.

Your Input

Estimation of particle size and mass density

In order to get started, you need a first estimate of the particle size (diameter in nm) and the mass density (in g/cm3) of your material, e.g. by scattering.

This information and a dispersion of your particles is all you need.

In the next step, you will calculate the concentration and prepare your BSA solution.

Create BSA solution

Using the information you gathered about your sample so far, it's now possible to determine the needed concentration of the bovine serum albumin (BSA) solution. Please provide all the input below:

Arbitrary or irregular

The particle dispersion concentration can be set anywhere between 20 and 500 µg/ml. Within these limits, the amount of nanoparticles visible on the TEM grid permits good quality image analysis.

Concentration of dispersion has to be ≥20 µg/ml and ≤ 500 µg/ml
Particle size has to be > 0 nm
Rod length has to be > 0 nm
Aspect ratio has to be ≥ 1
Particle mass densitiy has to be > 0 g/cm3

If you have questions containing the inputs you should provide, please don't hesitate to contact us.

Used input

Dispersion concentration:
Particle size:
Particle mass density:


Important: The BSA solution has to be sonicated for 10 min prior to use.

Note: BSA solutions can be stored for 1 month in the fridge (4℃).

Prepare dispersions

Now you can prepare your sample for microscopy. Just mix your nanoparticle dispersion with the prepared BSA solution in a 1:1 ratio and allow the dispersion to incubate for at least two hoursbefore preparing the TEM grid. In case of incubation overnight, incubate the dispersion in the fridge. You will need 5 µl for the TEM grid.

Image acquistion

Put a drop of 5 µL onto a TEM grid and record an image with the TEM. Once you have this done, you can proceed with the image analysis.


Analysis of the TEM image can be done manually by counting or in an automated fashion.

There are many different ways to do the image analysis automatically. One very simple way is to use Fiji, apply a binarization to your image via a threshold and run the particle analysis tool. Please visit the Fiji documentation for more details.

If you have any questions or remarks, please get in touch with us. If you used and liked the tool, please cite us.

 Contact us

Want to get in touch? Let us know!

 Cite us

Used it? Liked it? Cite it!