Improved micro-perfusion chamber for multiple and rapid solution exchange in adherent single cells

Area of Science:

• Cell biology
• Electrophysiology
• Biophysics

Background:

• Patch-clamp electrophysiology is crucial for studying ion channel function.
• Existing perfusion methods can be slow, require large solution volumes, and risk contamination.
• Efficient perfusion is essential for accurate and reproducible cell-based assays.

Purpose of the Study:

• To introduce a new micro-perfusion chamber (MPC) for fast and localized solution exchange.
• To enable whole-cell and single-channel patch-clamp recordings with improved solution control.
• To demonstrate the advantages of the MPC for studying single adherent cells.

Main Methods:

• A micro-perfusion chamber (MPC) was designed using a silicone rubber ring to isolate a small volume around a single cell.
• Whole-cell and single-channel patch-clamp recordings were performed within the MPC.
• Solution exchange speed was measured using patch pipette tip potential changes.
• The seal integrity of the MPC was assessed via electrical resistance measurements.
• Radioactive ligand ([3H]isradipine) was used to evaluate solution containment.

Main Results:

• The MPC allows for rapid solution exchange around single cells with an estimated speed of 16 +/- 5 ms.
• The method requires only small volumes of test solution (50 microliters).
• High electrical resistance (300-500 M omega) confirmed a good seal between the MPC and the Petri dish.
• Radioactive tracer experiments indicated effective containment of the perfusate within the MPC.

Conclusions:

• The developed micro-perfusion chamber (MPC) provides a significant advancement for patch-clamp electrophysiology.
• This technique facilitates precise control over the cellular microenvironment during recordings.
• The MPC method is efficient, conserves reagents, and minimizes cross-contamination, enhancing the reliability of single-cell studies.