The concentration ratio of glycated to non-glycated forms of various blood proteins can be used as a diagnostic
measure in diabetes to determine a history of glycemic compliance. Depending on a protein’s half-life in blood,
compliance can be assessed from a few days to several months in the past, which can then be used to provide additional
therapeutic guidance. Current glycated protein detection methods are limited in their ability to measure multiple proteins,
and are susceptible to interference from other blood pathologies. In this study, we developed and characterized DNA
aptamers for use in Surface Plasmon Resonance (SPR) sensors to assess the blood protein hemoglobin. The aptamers
were developed by way of a modified Systematic Evolution of Ligands by Exponential Enrichment (SELEX) process
which selects DNA sequences that have a high binding affinity to a specific protein. DNA products resulting from this
process are sequenced and identified aptamers are then synthesized. The SELEX process was performed to produce
aptamers for a glycated form of hemoglobin. Equilibrium dissociation constants for the binding of the identified aptamer
to glycated hemoglobin, hemoglobin, and fibrinogen were calculated from fitted Langmuir isotherms obtained through
SPR. These constants were determined to be 94 nM, 147 nM, and 244 nM respectively. This aptamer can potentially be
used to create a SPR aptamer based biosensor for detection of glycated hemoglobin, a technology that has the potential to
deliver low-cost and immediate glycemic compliance assessment in either a clinical or home setting.
|