These 2 or 3-chambered PTFE equilibrium dialyzers have been redesigned for 50 and 100 μl volumes with 4.2× larger membrane surface areas for fast equilibration. They consist of two sealable chambers of equal volume either 25, 50, 100, 250 or 500 μl Μ separated by a membrane between them. Open-top chambers facilitate sample introduction and withdrawal. Protein-ligand and protein-protein experiments are easily accomplished using a full range of membranes with MWCO of 100, 500, 1000, 2000, 5000, 10,000, 25,000, 50,000 or 100,000 Daltons. The entire dialyzer can be placed in a temperature-controlled device for faster equilibration. The system maintains the ease of use of the older design while increasing the dialysis speed by 4.2 times.