PICK. MEASURE. RELEASE. REPEAT.
EXCHANGEABLE COLLOIDAL PROBE
GAIN 10x THROUGHPUT AND MUCH MORE FREEDOM.
Colloids are ubiquitous in both industry and nature, being the key component in emulsions, foams, gels and aerosols.
The traditional colloidal probe technique allows to study single colloids by gluing them onto an atomic force (AFM) cantilever leading to valuable insights about colloid-colloid or colloid-substrate interactions. Yet the procedure is complex and throughput low.
With FluidFM, colloidal probe measurements become orders of magnitude easier and faster.
Fast and easy. In this video, three micrometer colloids are attracted from suspension with a vacuum, held briefly, and then released again with a pressure pulse.
Pick a colloid from solution or substrate with negative pressure. Measure. Release it with a pressure pulse. Repeat.
COLLOIDS A DAY
THAN STANDARD METHODS
0.5 to 100 µm
SUPPORTED PARTICLE SIZE
A COLLOIDAL PROBE WHICH CAN BE EXCHANGED
By applying a negative pressure inside, FluidFM micropipettes and nanopipettes can be used to attract floating colloids - or pick them up directly from a surface.
The process takes less than a minute and results in a colloidal probe with very repeatable cantilever position as the FluidFM aperture automatically centers the colloid.
After the measurement it can be removed from the cantilever with a positive pressure pulse, before attaching a fresh colloid to the probe.
Colloid for cell measurements. A 20 micrometer colloid is picked up by a FluidFM micropipette. 1. Before pickup.
2. Colloid is attached and ready for measurements.
Measure 100 colloidal probes in one day
The simple physical principle enables measurements of dozens of colloids in an hour if desired. All with the same FluidFM probe. It is common that one FluidFM probe can be used for several experiment days, given proper care and storage.
From sub-µm to 100 µm
FluidFM addresses the largest range of colloid dimensions. Our customers reported to work with colloid sizes from 500 nm up to 100 µm. Using focused ion beam the FluidFM probes can be further modified and even smaller or larger particles are potentially in reach.
Switch colloidal probe anytime
Whether the colloidal probe is degraded, has become contaminated or you simply want to change the probe geometry or chemistry – you can switch the colloidal probe at anytime.
The colloid position on the FluidFM cantilever is given by the FluidFM aperture. Thus, every colloidal probe will be centered automatically and at the same position – as long as the same FluidFM probe is used.
Measure in air or liquid
While most of our customer work with colloids in liquids, others have used FluidFM to pick up and measure particles and microorganisms in air.
Explore liquid and gaseous colloidal probes
The FluidFM colloidal probe works solely using physical microfluidic forces; no glue needed. This also means that the user can potentially hold microscopic droplets or bubbles in the same manner. There is much left to explore.
Three micrometer colloids are picked up by a FluidFM micropipette and are used as colloidal probe.
This transparent colloid of 50 micrometer diameter acts as lense, magnifying the FluidFM micropipette opening as it is held tightly by it.
In a few seconds, a 50 µm silica bead is targeted and immobilized with a FluidFM micropipette having 8 µm aperture size. Upon suction application, the bead is removed from the substrate and is ready to be used.
FluidFM has a huge potential for colloidal probe experiments. Below, we present 3 highlight publications; many more can be found in our publications section.
Industry relevant colloids typically range from 1 nm to 1000 nm, yet the classical colloidal probe technique works with colloids of 1 µm or larger. Here, researchers from the University of Bayreuth and ETH Zurich present a new method using FluidFM which unlocks the use of colloidal probes below 1 µm.
N. Helfricht, A. Mark, L. Dorwling-Carter, T. Zambelli and G. Papastavrou. Extending the Limits of Direct Force Measurements: Colloidal Probes from Sub – Micron Particles. Nanoscale. doi: 10.1039/C7NR02226C.
Often colloids can consist of soft biological material. In contrast, the established colloidal probe technique mainly works with hard colloids – mostly due to the high complexity of gluing soft colloids to the cantilever. Here, researchers from the University of Bayreuth describe a universal approach using FluidFM to measure soft colloids.
A. Mark, N. Helfricht, A. Rauh, M. Karg & G. Papastavrou. The Next Generation of Colloidal Probes: A Universal Approach for Soft and Ultra‐Small Particles. (2019) Small. Doi:10.1002/smll.201902976
Characterizing soft material
3D printing has become prevalent in many fields, especially in tissue engineering. Yet so far it was not possible to melt-electrowrite (MEW) hydrogels, limiting print architecture and resolution of this important material in biomedicine. Researchers from The Julius Maximilians University of Würzburg and the University Hospital Würzburg have discovered a way unlocking MEW with promising implications to directly print soft, yet resilient tissues. FluidFM helped to characterize the printed material with its fast colloidal probe technique.
D. Nahm, F. Weigl, N. Schaefer, A. Sancho, A. Frank, J. Groll, C. Villmann, H.W. Schmidt, P. Dalton, R. Luxenhofer. A versatile biomaterial ink platform for the melt electrowriting of chemically-crosslinked hydrogels. (2019) Materials Horizon. Doi:10.1039/C9MH01654F