When working with cells, colloids or other sticky materials, a repellent coating of the probe outside is advised. We recommend to use PLL(20)-g[3.5]- PEG(2) from SuSoS.
This coating protocol is based on Dörig et al. (2010), Potthoff et al. (2012) and Guillaume-Gentil et al. (2014).
Recommended: Plasma clean your FluidFM probe to improve the coating.
- Prepare 500 ul of 0.5 mg/ml PLL-g-PEG. Use HEPES2 or PBS as buffer.
- Optional: heat PLL-g-PEG and probe to 80 °C for an improved coating quality.
- Fill probe container with 10 ul PLL-g-PEG solution.
- Mount probe on AFM.
- Fill probe tubing with PLL-g-PEG by applying an overpressure of 50 mbar to 1 bar until the liquid reaches the opening.
- Take off the probe and put it in to the packaging.
- Immerse the probe in PLL-g-PEG solution for 1 hour.
- For this you can leave the probe in the blister pack and add 300 ul PLLgPEG solution on top of the probe. The pocket in the blister pack will act as liquid container.
- Optional: Perform this step at 80 °C for an improved coating quality. Instead of the blister you will have to use a glass container and several ml of PLLgPEG solution when coating at 80 °C.
- Protect the probe from dust, for example with a Petri dish.
- Rinse the CytoClip and cantilever in filtered ddH2O for 5-10 minutes.
Dörig, P., Stiefel, P., Behr, P., Sarajlic, E., Bijl, D., Gabi, M., … Zambelli, T. (2010). Force-controlled spatial manipulation of viable mammalian cells and micro-organisms by means of FluidFM technology. Applied Physics Letters, 97(2), 023701 1–3. doi:10.1063/1.3462979
Potthoff, E., Guillaume-Gentil, O., Ossola, D., Polesel-Maris, J., LeibundGut-Landmann, S., Zambelli, T., & Vorholt, J. A. (2012). Rapid and Serial Quantification of Adhesion Forces of Yeast and Mammalian Cells. PLoS ONE, 7(12), e52712. doi:10.1371/journal.pone.0052712
Guillaume-Gentil, O., Zambelli, T., & Vorholt, J. (2014). Isolation of single mammalian cells from adherent cultures by fluidic force microscopy. Lab on a Chip, 14(2), 402–14. doi:10.1039/c3lc51174j