Affinity and mobility of polyclonal anti-dansyl antibodies sequestered within sol-gel-derived biogels

We report on the equilibrium binding affinity and rotational reorientation dynamics of intact polyclonal anti-dansyl antibodies (anti-DAN) sequestered within sol-gel-derived biogels. Our results show that the nanosecond rotational motions that are intrinsic to immunoglobulin G antibodies when they are dissolved in aqueous buffer are arrested in an aged biogel. However, even though the anti-DAN rotational mobility is not detectable in a biogel, the equilibrium binding constant (K(b)) that describes the anti-DAN association with its target hapten (dansyl, DAN) in a biogel is only 5-fold less than the value for anti-DAN dissolved in aqueous buffer (4.09 ± 0.10 x 10⁸ M^-1 vs 9.04 ± 0.32 x 10⁷ M^-1). Long-term storage experiments on the anti-DAN-doped biogels stored at room temperature show that K(b) remains constant for at least 8 months.