Diffusion studies in gels using holographic laser interferometry

Abstract: This thesis is an investigation of the potential of holographic laser interferometry for the study of diffusion of both small solutes and macromolecules. An investigation on the importance of errors due to light deflection in refarctive index gradients showed that the magnitude of the refractive index gradients were negligible for the system investigated. The holographic interferometry technique requires a high stability to study diffusion of macromolecules. This was achieved by a proper design and hence the diffusion coefficients for BSA, lysozyme and pullulan in agarose gels were succesfully obtained. The effect of solvent as well as the BSA and agarose concentration on the BSA diffusion coefficient and partition coefficient was investigated. In addition, the effect of the pullulan molar weight on the pullulan diffusion and partition coefficient in agarose gel was studied. The effect of pH and ionic strength on the lysozyme diffusion in agarose gel was studied. The experimental data was evaluated using a general transport model based on chemical potential gradients instead of concentration gradients. The chemical potential was estimated by using the Poisson-Boltzmann equation.