Logo of the Physikalisch-Technische Bundesanstalt

Cytological and Biomolecular Measuring Procedures

Working Group 8.32

Measurement of concentration of small particles


  Federal Ministry for Economic Affairs and Energy (grant MNPQ Projekt 13/14)

  09/2015 – 09/2018

Home built flow cytometer for detection of nanoparticles

The working group is developing methods for detection of sub-micron particles, nanoparticles, and even molecules in flow. DNA fragments, lipoproteins and other extracellular vesicles fall in this size range. Currently we extend our capabilities for detection of single particles in flow by light scattering in collaboration with our industry partner within a project funded by the German ministry of economics. The main focus lays on development and test of methods and techniques for detection of single sub-micron and nanoparticles.

Enhancement of the sensitivity of the detectors with concurrent reduction of scattered light background is essential for nanoparticle detection. Additionally it is necessary to enlarge the dynamic range of the detection to account for the signal dynamics for simultaneous detection of nano- and micro-particles.

The main goal of the project is to measure concurrently size distributions of nano- and micro-particles in suspension and to determine their concentration. Accurate concentration determination will be realised using a sample delivery system developed in the group. This system is based on calibrated syringes for sample volume control. In addition, the method for calibration of the syringes was also developed in the working group.


1. Hussels M.; Engel S.; Bock N.
Investigation of direct counting and sizing of DNA fragments in flow applying an improved data analysis and correction method
Opens external link in new windowBiomol. Detect. Quantif. 17 (2019) 100083.

2. Kammel, M.; Kummrow, A.; Neukammer, J.
Reference measurement procedures for the accurate determination of cell concentrations: present status and future developments
Opens external link in new windowJ. Lab. Med. 36 (2012) 25-34.

3. Reitz S.; Kummrow, A.; Kammel, M.; Neukammer, J.
Determination of micro-litre volumes with high accuracy for flow cytometric blood cell counting
Opens external link in new windowMeas. Sci. Technol. 21 (2010) 074006.

4. Neukammer, J.; Gohlke C.; Höpe, A.; Wessel, Th., and Rinneberg, H.
Angular-distribution of light scattered by single biological cells and oriented particle agglomerates
Opens external link in new windowApplied Optics 42 (2003) 6388-6397.