SYNTHESIS OF 4-CARBOXYPHENYLBORONIC ACID N-HYDROXYSUCCINIMIDE ESTER VIA CARBODIIMIDE/NHS COUPLING FOR GLUCOSE DETECTION
Wai Mak, Ace Galermo, Edmundo Perez, Rifat Ozel, Bakthan Singaram, Nader Pourmand.
University of California, Santa Cruz, Santa Cruz, CA.
The rising numbers of cases of diabetes in the United States and worldwide has increased the need for blood glucose monitoring devices. This has led researchers to develop non-enzymatic glucose sensors which are more robust, low-cost, and simple compared to enzymatic glucose sensors in the market today. One method for the development of such a sensor involves the attachment of boronic acids, a known saccharide receptor, onto a quartz nanopore. In order to investigate the feasibility of such a device, the boronic acid can be modified and studied in solution then transferred to its solid state counterpart. Using established methods, the synthesis of 4-carboxyphenylboronic acid N-hydroxysuccinimide ester (4-NHS-CPBA) was carried out using 4-carboxyphenylboronic acid (4-CPBA), N-hydroxysuccinimide (NHS), and by varying carbodiimide crosslinkers: N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) or N,N′-dicyclohexylcarbodiimide (DCC). The progress of each reaction was monitored using thin layer chromatography (TLC). Next, a pseudo amine analog was reacted with the 4-NHS-CPBA to mirror the attachment of the boronic acid onto an amine functionalized glass nanopore. Lastly, a sugar displacement assay was performed and analyzed via UV-Vis spectrometry to determine the binding affinity of several monosaccharides to the amine bound boronic acid receptor. Ultimately, the results of this study will act as a bridge between solution based and solid state chemistry for our boronic acid saccharide sensor. This would lead to further improvements in the field of non-enzymatic saccharide sensors for blood glucose monitoring.