Recently, aptamers have emerged as an innovative strategy for biosensing tools and biomedical diagnostic applications. Given their high affinity and specificity towards unique target molecules, herein, we explore the potential of these oligonucleotide sequences to target a detrimental contaminant found in drinkable water, inorganic arsenic (i.e., As3+, As5+). Initially, the aptasensor was fabricated by grafting the thiol-end of the aptamer onto a gold electrode. Then, to test the aptamer’s interaction with arsenic, the modified electrode was submerged in a sodium arsenite solution. Such process is expected to produce strong interactions between arsenic ions and the immobilized aptamers. The electrochemical performance of the sensor was characterized by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). EIS changes in resistance provided insight about the surface interactions of the electrodes. Specifically, an increase in electron transfer resistance is expected once the modified electrode comes in contact with the arsenic. Experimental results show that the degree of resistance correlates well with the concentration of the target molecule. Such data indicate that our aptasensor can be further developed as an out-of-lab arsenic sensing platform. The capacity of our system to detect arsenic trioxide and arsenic pentoxide in water could reveal a new generation of water remediation nanotechnology.

Towards an arsenic-specific aptasensor based on AuNPs/thiol interactions

253rd National Meeting (2017)

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