If you’ve ever applied a FISH probe and watched it
bead up instead of spreading evenly, you’re not alone—and it’s one of the most common issues labs encounter during hybridization.
In this edition of
Teagan’s Tech Tip, we break down
why probe beading happens and, more importantly,
how to prevent it to ensure consistent coverage and reliable results.
In this tech tip, you’ll learn:
- The most common causes of probe beading on the slide
- How surface tension and slide prep impact probe behavior
- Simple adjustments that improve probe spread and uniformity
- Best practices to help ensure consistent hybridization and signal quality
Small changes in technique can make a big difference in FISH performance. This quick, practical tip is designed to help your lab reduce variability and improve confidence in every run.
Master the Spread: Eliminating Probe Beading in FISH
Have you ever applied a FISH probe only to watch it bead up instead of spreading evenly? You aren’t alone. Improper probe spread is one of the most common hurdles in the lab, often leading to uneven hybridization and unreliable signals.
In this edition of
Teagan’s Tech Tips, we break down the science of surface tension and slide prep to help you ensure consistent coverage and high-quality results every time.
| Feature |
The Technique |
Why It Matters |
| Temperature |
Let probes reach full room temperature before use. |
Hybridization buffer is naturally viscous and thickens further in the freezer. Warming “loosens” the solution for better flow. |
| Desiccation |
Ensure slides are “dry like the desert” before application. |
Residual alcohol or fixative creates surface tension issues. Complete evaporation prevents the probe from reacting with unwanted elements. |
| Application |
Apply probe to the coverslip, then lower the slide onto it. |
Laying the slide upside down onto the coverslip minimizes air bubbles and ensures the probe reaches every corner of the region of interest. |
| Homogeneity |
Vortex for 10 seconds, hitting different angles of the vial. |
Probe concentrate is thinner than the buffer. Thorough mixing ensures the solution is uniform before it touches the slide. |
| Volume |
Use the full recommended volume—don’t skimp. |
Using too little volume causes “edge effects,” where the quality of your sample drops off at the perimeter of the coverslip. |
Best Practices for Success
- Eliminate Air: After applying the coverslip, gently tap out any visible bubbles. Air pockets are the enemy of even hybridization.
- Surface Prep: Consistency in slide pretreatment is key to managing how the probe interacts with the glass surface.
- Uniformity: Small adjustments in your mixing and warming routine can drastically reduce variability between different runs.
Expert Insight: “Small changes in technique make a big difference in FISH performance. By managing viscosity and surface tension, you improve confidence in every signal you score.” — Teagan
