Session: Analytical Division Poster:

Our research efforts focus on the development of diagnostic sensors, specifically for bacterial detection. The sensor concept is based on DNA aptamers which are artificial, single-stranded DNA molecules typically shorter than 100 nucleotides. Aptamers continue to be widely used for analytical detection and diagnostic applications as they display the ability to bind, and therefore identify, specific target molecules with remarkably high selectivity based on their tertiary structure.
We isolated aptamers with high affinity to p57 or Major Soluble Antigen (MSA), the principal antigenic protein found on the surface of Renibacterium salmoninarum, which is responsible for bacterial kidney disease in salmonids. Specifically, we targeted the R2c sub-construct from region 2 which contains a putative DNA-binding domain and therefore is believed to be a good binding site for aptamers. Aptamers were identified from a large, random pool through a process called Systematic Evolution of Ligands by Exponential amplification (SELEX). After the SELEX cycles, aptamers were then sequenced to determine the aptamer(s) with the largest binding affinity to the DNA-binding domain in R2C.
The current SELEX method has been modified to incorporate graphene oxide. This approach is based on recent findings that ssDNA can interact strongly via p-p stacking with graphene oxide sheets, making graphene oxide an excellent tool to help enrich pools of DNA with high affinity to the target and much-increased efficiency. The method eliminates the use of affinity chromatography to immobilize the target, making the entire process much simpler, rapid, and cost-effective.

Brady R Layman

Undergraduate Student, Eastern Oregon University

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