Bead based microreactors for sensing applications

The dissertation research described here focuses on the fabrication and modification of the polymeric beaded sensing elements, one of the many critical components of a Microbead Array Chip-Based Multianalyte Detection System. Detection of biomolecules including proteins and oligonucleotides are based on affinity interactions between carefully selected ligands immobilized on the sensing microspheres. The current work relies on microspheres made of agarose gel shaped into micron sized beads with intrinsic porosity associated to the concentration of agarose in the gel. The beaded material described is considered of a homogeneous nature with limited transport capabilities although superior to homogeneous latex beads. The microbead array system potentially benefits from structural modifications on the sensing elements and includes improvement on the mobile phase mass transport, capture of larger particles, faster assays, and the increase in the multiplexing capabilities. Efforts are also directed to preferentially modify gels made of agarose to facilitate the transition from the existing sensing elements to the new beaded designs made of the same polysaccharide. As a result the chemistry utilized to attach affinity ligands to procure reactive sensing elements remained practically the same. Collectively, these research activities have resulted in a number of novel polymer-based reactive particles that have the potential to service a variety of new sensing applications.