Functionalized hydrogel microparticles prepared by microfluidics and their interaction with tumour marker carbonic anhydrase IX.

Microfluidics allows precise control of the synthesis of microparticles for specific applications, where size and morphology play an important role. In this work, we have introduced microfluidic chip design with dedicated extraction and gelation sections allowing to prepare hydrogel particles in the size range of a red blood cell. The influence of the extractive channel size, alginate concentration and type of storage media on the final size of the prepared alginate microparticles has been discussed. The second part of the work is dedicated to the surface modification of prepared particles using chitosan, pHPMA and the monoclonal antibody molecule, IgG M75. The specific interaction of the antibody molecule with an antigen domain of carbonic anhydrase IX, the transmembrane tumour protein associated with several types of cancer, is demonstrated by fluorescence imaging and compared to an isotypic antibody molecule.

Effects of constant electric fields on the buoyant stability of reaction fronts.

The effects that applying constant electric fields have on the buoyant instability of reaction fronts propagating vertically in a Hele-Shaw cell are investigated for a range of electric field strengths and fluid parameters. The reaction produces a decrease in density across the front such that upwards propagating fronts are buoyantly unstable in the field-free situation. The reaction kinetics are modeled by cubic autocatalysis. A linear stability analysis reveals that a positive electric field increases the stability of a reaction front and can stabilize an otherwise unstable front. A negative field has the opposite effect, making the reaction front more unstable. Numerical simulations of the full nonlinear problem confirm these predictions and show the development of cellular fingers on unstable fronts. These simulations show that the electric field effects on the reaction within the front can alter the fluid density so as to give the possibility of destabilizing an otherwise stable downward propagating front.