Biosensors use biomolecules, such as enzymes, to recognize a particular molecule of interest and ideally produce an easily measured signal. A single enzyme may be capable of serving as a biosensor, but often a second enzyme that is capable of reacting with the product of the sensing enzyme is necessary to generate this signal. Horseradish peroxidase is commonly used because it reacts with products from numerous enzymes, including glucose oxidase, and a chromogenic substrate to produce a product that is both visible and easily monitored with simple instrumentation. Alternative biomolecules are increasingly being used alongside or in place of protein enzymes in biosensors. For example, deoxyribozymes are single-stranded DNA sequences that mimic protein enzymes, yet are readily synthesized and stable under a variety of conditions, making them ideal components for biosensors. A challenge in pairing enzymatic components in a biosensor is how to optimize the product transfer from the sensing component to the signaling component. Immobilization and localization may be used to combat product diffusion in solution, thereby enhancing communication between components and resulting in an improved signaling system. One approach is to immobilize enzymatic components on a multiply-branched DNA scaffold, known as comb-branched DNA, which will secure components within close and adjustable proximity. To demonstrate the utility of comb-branched DNA in biosensors, we are immobilizing glucose oxidase and a peroxidase deoxyribozyme on comb-branched DNA and testing the ability of this construct to sense glucose. Efforts on constructing this glucose biosensor and comparisons of signaling activity to assays of enzymatic components free in solution will be discussed.

Using comb-branched DNA to construct deoxyribozyme-based biosensors

253rd National Meeting (2017)

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