Design of an optimised microfluidic environment in the context of silver nanoparticle detection


Silver nanoparticles (AgNPs) exhibit favourable characteristics such as antibacterial, antifungal, antiviral, and antiinflammatory activity, rendering them of great interest for many biomedical applications. Their outstanding usage raising concerns about the AgNPs’ interaction with biological material both at the nano- and macroscale, since a potential risk of short- and longterm toxicity was reported1,2. To understand large-scale impacts of AgNPs on the environment and to reveal the level at which AgNPs are present, there is a necessity for a sensor device to detect and characterize AgNPs in solution. Here, we use an electrochemical detection method based on the oxidation of AgNPs at an appropriately biased electrode to estimate the underlying AgNP concentration in solution3,4. Although the detection itself is a stochastic process, the detection frequency follows mean-field statistics5. Towards a reliable flow-over sensor system, we want to use a microfluidic environment to enhance the detection frequency that is currently governed by passive diffusion6,7.

Aim & Research Methods

In this project we want to develop a microfluidic system specifically tailored to the requirements of an optimised AgNP detection including passive fluid mixing and the adjustment to an appropriate flow rate. Your task will be to:

  1. design different microfluidic systems with a common CAD program based on theoretical considerations and/or finite element simulations, 
  2. construct microfluidic flow-over sensor systems by means of stereolithography printing and clean-room fabricated detection chip,
  3. perform AgNP detection experiments with our custom-built system and evaluate the results with regard to performance criteria such as efficiency and sensitivity.

You will be introduced in an interdisciplinary working environment and will learn the following techniques:

  1. finite element simulation with COMSOL
  2. stereolithographic printing
  3. electrochemical characterization methods (amperometry, impedance spectroscopy)


  1. experience with CAD design of mechanical parts
  2. excellent analytical and experimental skills
  3. dedication and motivation to work on an interdisciplinary research topic self-reliantly
  4. programming skills for data analysis (e.g. Matlab or Python)

Possible starting date & further information

Potential starting date is as soon as possible. For further details and application contact Lennart Weiß in person or via email (see contact information below).


  1. L. Ge et al., “Nanosilver particles in medical applications: synthesis, performance, and toxicity,” International Journal of Nanomedicine, vol. 9, pp. 2399-2407, 2014.
  2. E. Navarro et al., “Environmental behavior and ecotoxicity of engineered nanoparticles to algae, plants, and fungi,” Ecotoxicology, vol. 17, pp. 372-386, 2008.
  3. E. Tanner, C. Batchelor-McAuley and R. Compton, “Single nanoparticle detection in ionic liquids,” The Journal of Physical Chemistry C, vol. 120, pp. 1959-1965, 2016.
  4. K. Krause, A. Yakushenko and B. Wolfrum, “Stochastic On-Chip Detection of Subpicomolar,” Analytical Chemistry, vol. 87, pp. 7321-7325, 2015.
  5. S. Eloul, E. Kätelhön, C. Batchelor-McAuley, K. Tschulik and R. Compton, “Diffusional impacts of nanoparticles on microdisc and microwire electrodes: The limit of detection and first passage statistics,” Journal of Electroanalytical Chemistry, vol. 755, pp. 136