ARTGEL: A temperature-regulated gel electrophoresis platform for quantitative studies of reversible association

Here we present ARTGEL, an actively regulated-temperature gel electrophoresis platform designed for quantitative studies of temperature-sensitive reversible biomolecular association. Existing literature describes electrophoretic mobility shift assays in which biomolecular reactions are suppressed during electrophoresis through dilution, the use of competitors, or reduced temperature. These approaches can alter temperature-sensitive equilibria and may cause the gel to report a state different from that of the original bulk solution. Rather than attempting to quench reactions, ARTGEL enables electrophoresis to be performed at the same temperature as complementary bulk measurements, allowing reversible association to be quantified directly in the gel and compared with matched measurements in solution. The ARTGEL platform integrates feedback-controlled thermoelectric regulation of gel temperature, a large, heated, and continuously circulated buffer reservoir to help maintain ionic strength, and automated electrode-wiping to mitigate electrode fouling and maintain stable electrophoresis current during long-duration electrophoresis. During electrophoresis, ARTGEL maintained the gel temperature at 30°C setpoint with a temporal variation of 0.03°C and a spatial range of 0.6°C. With periodic automated electrode wiping, the electrophoresis current remained at 139.5 $\pm$ 2.5 mA during the 24-h experiment. Using DNA origami assemblies, we further show that ARTGEL preserves distinct temperature-dependent association states, resolves reaction-dependent distortions of migrating bands, and supports extraction of in-gel kinetic and thermodynamic parameters from reaction-diffusion-advection modeling.