| Analyses for the presence and/or concentration of biological species are of importance for both diagnostic and research purposes. One of the most useful techniques for such analyses is enzyme linked immunosorbent assay (ELISA). Although considerable effort has led to remarkable improvements and innovations in the development of ELISA applications, there are still aspects of this technique that can be improved, amongst which are reduction in the amount of inputs (sample size, reagents and energy), improvements in sensitivity, and the ease of use. One strategy for accomplishing these improvements is through the use of microfluidics. Microfluidics has to do with the behavior and manipulation of fluids within geometrically constrained structures. Not surprisingly, ELISAs have been implemented in microfluidic devices. While complex microfluidic designs have produced impressive results, it may be possible to further improve this platform by applying organic chemistry to some of the aspects of its operation. In this dissertation, some applications of organic chemistry are discussed in which specially designed ELISA substrates are synthesized that take advantage of the unique ability of microfluidics to rapidly and efficiently separate charged species. This has allowed us to detect enzyme catalyzed reactions on the basis of a changes in the charge state that occur on the enzyme mediated conversion of substrate to product, rather than changes in the chromophoric properties that is the basis for all current ELISA methods. We have also designed and synthesized specialized coatings for use in decreasing non-specific binding of proteins to microfluidic channels, which should allow for substantial improvements in the sensitivities of microfluidic ELISAs, as well as improve some microfluidic separations. |
