Seal enhancers on the Qube 384: An alternative to fluoride

Gigaohm seals, or ‘gigaseals’, are imperative to patch clamp electrophysiology to enable good electrical access to the cell and high-quality recordings. Metrion Biosciences and Sophion Bioscience have collaborated to determine whether other insoluble salts can act as seal enhancers, or whether this property is unique to CaF₂ The results include:

• Solubility and Gigaseal Formation: BaSO₄ and SrCO₃ have low solubility (low Ksp values), similar to CaF₂. However, only BaSO₄ successfully facilitated gigaseal formation comparable to CaF₂, indicating no direct correlation between K_sp values and gigaseal formation ability.
• Effectiveness of BaSO₄: BaSO₄ emerged as a potential alternative seal enhancer to CaF₂, as it does not alter ion channel function or cellular signaling pathways, making it advantageous for gigaseal formation.
• Optimal Ba2+ Concentration: High resistance gigaohm seals formed only with ≥ 3 mM extracellular Ba²⁺, though this concentration may block K⁺ channels, necessitating further investigation to determine its suitability for preserving channel function.