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No small, portable and user-friendly method for measuring droplets or counting particles in air exists at the moment

Our sensor can be used for:

  • counting droplets in the air to prevent disease spreading (medical / hospital),

  • testing of inhalers-dosed drugs (medical / pharmacy),

  • analysis of droplets in the clouds (meteorology) and spray mist (agriculture),

  • monitoring of air pollution with particles (air quality).

We are interested in partnering with Industry or Academia / Research to further develop the technology. We are also interested in pilot projects with organizations with access to potential users and use cases for our innovative and portable air quality measurement device.

Our miniaturized sensor for nanoparticles is based on the detection of the time-dependent capacitance. The measured change of the capacitance is caused by the impact of a nanoparticle covered with condensed water, to the water situated in the sensor. The impact of the nanoparticle, causes a crater in the water, which causes the change in the capacitance. A proof-of-concept was already demonstrated, patented (US 9,151,724 B2), and published in peer reviewed journals.


Figure: a) Design of the condensation particle chamber and the position of the sensor. b) The sensor with two parallel electrodes and droplets encapsulating nanoparticles (Iskra, I., Detela, A., Viršek, M., Nemanič, V., Križaj, D., Golob, D., … Remškar, M. (2010). Capacitive-type counter of nanoparticles in air. Applied Physics Letters, 96(9), 093504. doi:10.1063/1.3352554 )


Jožef Stefan Institute (JSI) (, is the leading Slovenian scientific research institution, covering a broad spectrum of basic and applied research. The staff of about 1000 specializes in natural sciences, life sciences, and engineering.
Project team: Gregor Filipič, PhD in physics; Darko Kavšek, electro-engineer.

Nanotul, Ltd. ( is a spin-off company of JSI. It was established in 2007 and is specialized in the synthesis and commercialization of nanomaterials and testing of air pollution by nanoparticles.
Project team: Maja Remškar, PhD in physics, director and inventor; Ivan Iskra, PhD in electro-engineering, inventor; Matjaž Malok, MSc in mechatronics.

Funded by

EIT Health InnoStars RIS Innovation 2022 Call

Funding of high-quality, early-stage healthcare projects in the proof-of-concept phase, which target EIT Health’s six Focus Areas and to be developed by local actors including both business and academic/research/healthcare institutions.

Title of the funding project: Miniaturised sensor for monitoring and prevention of airborne inflicted diseases

Partners: Jozef Stefan Institute and Nanotul d.o.o.

Local EIT Health RIS Hub: Ljubljana University Incubator

Project abstract: We are developing a tool for the detection of nanoparticles in air in a size range, which also covers the size of the coronavirus. Currently, hospitals and care institutions do not have any cheap and miniaturized instrument to control the quality (i.e. aerosol concentration) of indoor air. Therefore, extensive and expensive air filtration systems, disinfection and/or air exchangers are used without knowing the actual state. In particular, in nursing homes and health care institutions the fast spread of the coronavirus was assigned to air condition systems. A detector for nanoparticles would be a useful tool to prevent such events in future. The sensor principle is innovative and patent protected by US patent (US 9,151,724 B2). We are the owners of the IPR.