Fast Measurement of Protein-ligand Kinetics Using Dual Slope Spr Microchips

We demonstrate a new dual slope SPR technique that is twenty-fold faster than the conventional step-response method. The new scheme utilizes rapid slope-based measurements followed by rapid reset and it separates association and dissociation half reaction measurements at two separate sites inside a dual-chamber PDMS microfluidic chip. For an model CAII-ABS test system, the association and dissociation slopes were measured in 30 seconds compared to 10 minutes for step-response. The values of ka and kd calculated from the fast slope method are 5.0×10 3 1/(Ms) and 4.8×10 -2 1/s, matching well with stepresponse values while facilitating ~15-25x fold faster detection and quantification. The overall figure of merit is twice that of the step response method.