Electrical detection of proteins and nucleic acids using the electrokinetic effect in a silica microcapillary

Abstract: Electrical detection of humanized Immunoglobulin G and single stranded DNA having different mismatched contents is presented in this thesis. For electrical detection a simple method relying on streaming current measurement in a functionalized silica capillary was used. Immobilization of the DNA capture probe on a capillary surface was done by standard chemical functionalization technique. The interaction of the immobilized DNA capture probes and their complimentary ssDNA having different mutations was studied for different concentration of target probes. The specificity and the reproducibility of the interactions were investigated by a number of control measurements and repeated measurements. For IgG detection, Z domain, an IgG binding partner, was immobilized by traditional chemical functionalization strategy as well as a novel recombinant silk-based technique. The silk-based approach allows a fast and high-density capture probe immobilization with a simple one-step coating. The specific interaction of IgG with its binding partner was investigated for different concentrations of IgG. A comparison of the two functionalization techniques is presented in addition to the degree of non-specific interaction in both cases.