Functional Nucleic Acid-Directed Assembly of Nanomaterials and Their Applications as Colorimetric and Fluorescent Sensors for Trace Contaminants in Water

This chapter highlights some of the major strengths of combining nucleic acids with nanotechnology: Nucleic acids provide a general class of molecules that can be selected to recognize a variety of different contaminants; In vitro selection can be utilized to tailor the sensitivity and specificity of the nucleic acid for the contaminant, so as to obtain better sensors; Functional nucleic acids can be readily labeled with fluorophores and inorganic nanoparticles to obtain sensors with tunable dynamic ranges; The sensors can be assembled into dipstick tests and devices for ease of use, longer shelf life, and regeneration. In spite of the generality of nucleic acid sensors, there still exist challenges in selecting nucleic acids for certain kinds of analytes, such as anions like perchlorate or nitrate, which are negatively charged and thus are repelled by the negatively charged backbone of nucleic acids. It is important to explore newer selection strategies to overcome these and further expand the repertoire of analytes recognized.