Functional DNA based nanosensors for environmental monitoring

ANA SOL PEINETTI; YI LU

Newry, Maine

Conferencia; Environmental Nanotechnology - Gordon Research Conferences; 2019

Gordon Research Conferences

In the Lu group, we develop highly sensitive and selective portable sensors for on-site, real-time, trace amount quantification of a broad range of environmental contaminant. By conjugating functional DNA (DNAzymes and aptamers) obtained from in vitro selection process with either fluorophore and quencher molecules and nanomaterials, we have developed new classes of fluorescent, colorimetric, and MRI agents, for detecting metal ions and a wide range of other targets with high sensitivity (down to 14 pM) and selectivity (> 1 million fold selectivity). In this work, we will present the results on developing sensors for waterborne infectious pathogens.We have used in vitro selection process to obtain an aptamer for a waterborne virus, Human Adenovirus (HAdV). Here, we aimed to push the boundaries of the selection process to distinguish the functionality of the virus (differentiate between active -infectious- and inactive virus) without knowing the inactivation mechanism, exploiting a rational design of the selection pressure to reach a maximum level of selectivity. Up to date, microbiology-based techniques are the only available method to differentiate the infectious states of the virus by performing assays with virus specific host cells that take several days.[14] After 11 round of selection we have obtain an aptamer that has a high affinity for the infectious HAdV with a Kd of 0.1nM. Furthermore, this aptamer presents great selectivity toward the active HAdV, while the signal for the inactive form of HAdV and other waterborne virus, Coxsackie virus, is low. This is the first evidence, of the best of our knowledge, of a molecular recognition element that can be used to distinguish the infectivity status of the virus. This open the opportunity for the on-site detection of virus with this level of differentiation capability. Also, we are developing a novel detection method that allows single molecule detection on a portable device. On one hand, DNA isothermal amplification, is used to convert each aptamer/DNAzyme binding event into multiple signal generating molecules within a relatively short period of time. On the other hand, this reaction happen in the confinement nanopore, reaching ultrasensitive detection of the target. So far, we have demonstrated that it is possible to detect a single DNA molecule in 2 mL.