Artificial lipid bilayers are indispensable in studying ion channel function, yet their practical application has long been hindered by mechanical fragility under fluid flow. This limitation restricts solution exchange rates, leading to prolonged assay times that impede high-throughput screening. We present a breakthrough platform based on hydrogel-stabilized droplet bilayers capable of withstanding solution flow speeds up to 2.1 m/s without rupture, enabling rapid and reliable ion channel measurements.
The core innovation lies in the use of agarose hydrogel droplets as supporting electrodes. These gel-tipped electrodes are fabricated by dispensing a 1% agarose solution into pipette tips, forming stable sessile droplets upon cooling. The hydrogel serves as a mechanically robust foundation for the lipid bilayer, which is formed at the interface between a lipid monolayer at an oil/aqueous boundary and another at an oil/hydrogel boundary.D-Glucose-13C6,d7 NF-κB A precision-cut aperture in a plastic film masks the bilayer formation zone, enhancing stability during dynamic perfusion.
We validated the system’s performance using gramicidin-A (gA) channels as a model. At a flow rate of 0.1 m/s (5 mL/min), we observed steady gA currents averaging ~180 pA with fluctuations of ~40 pA, consistent with multiple dimeric channel activity. When switching between 1 M KCl and 100 mM KCl/900 mM TEA-Cl solutions—designed to maintain osmotic balance while altering ion conductivity—we recorded distinct current levels: −2142 ± 5.0 pA and −29 ± 1.2 pA, respectively. Single-channel analysis confirmed step sizes of 1.85 ± 0.25 pA and 0.38 ± 0.11 pA, indicating a significant reduction in conductance due to lower K⁺ concentration and non-conductive TEA⁺ substitution.DOT1L ProteinMolecular Weight
A critical observation was the ~750 ms delay between solenoid valve actuation and measurable current change, matching the transit time of the tubing dead volume (~65 µL) at 5 mL/min. After this lag, the current reached 90% of its new steady-state value in just 2.7 seconds. COMSOL simulations of ion concentration dynamics predicted a 90% change in K⁺ concentration in 3.7 seconds, slightly slower than the measured response—suggesting additional factors such as a transient reduction in active gA channels during exchange may contribute to faster-than-expected current decay.
To demonstrate real-world utility, we applied the platform to measure TRPM8 channel modulation by menthol (agonist) and 2-APB (antagonist).PMID:35261153 In three independent experiments, EC50 values for menthol were 60.9, 45.4, and 70.7 µM—within the known range of 53–101 µM. IC50 values for 2-APB were 1.66, 2.69, and 3.31 µM, consistent with literature values (1.5–12 µM). Notably, full dose-response curves for four concentrations were completed in under 4 minutes, and eight concentrations in approximately 7 minutes—representing a >10-fold reduction in assay time compared to conventional methods.
The system’s advantages extend beyond speed. Gel-tipped electrodes can be pre-fabricated, stored at 4°C for weeks, and integrated into automated multi-well arrays. Unlike solid-supported bilayers, they support constant voltage application and direct current measurement, essential for accurate conductance quantification. The entire setup is compatible with robotic fluid handling, enabling parallelization and scalability.
This hydrogel-stabilized platform bridges the gap between fragile freestanding bilayers and rigid solid-supported systems, combining mechanical durability with electrophysiological fidelity. Its ability to perform rapid, repeatable, and high-resolution ion channel assays positions it as a transformative tool for drug discovery, toxicology screening, and fundamental biophysics research.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com