Multiplexed Aptasensors and Amplified DNA Sensors Using Functionalized Graphene Oxide: Application for Logic Gate Operations

Abstract

Graphene oxide (GO) is implemented as a functional matrix for developing fluorescent sensors for the amplified multiplexed detection of DNA, aptamer-substrate complexes, and for the integration of predesigned DNA constructs that activate logic gate operations. Fluorophore-labeled DNA strands acting as probes for two different DNA targets are adsorbed onto GO, leading to the quenching of the luminescence of the fluorophores. Desorption of the probes from the GO, through hybridization with the target DNAs, leads to the fluorescence of the respective label. By coupling exonuclease III, Exo III, to the system, the recycling of the target DNAs is demonstrated, and this leads to the amplified detection of the DNA targets (detection limit 5 × 10(-12) M). Similarly, adsorption of fluorophore-functionalized aptamers against thrombin or ATP onto the GO leads to the desorption of the aptamer-substrate complexes from GO and to the triggering of the luminescence corresponding to the respective fluorophore, thus, allowing the multiplexed analysis of the aptamer-substrate complexes. By designing functional fluorophore-labeled DNA constructs and their interaction with GO, in the presence (or absence) of nucleic acids, or two different substrates for aptamers, as inputs, the activation of the "OR" and "AND" logic gates is demonstrated.

Fluorescent sensors using DNA-functionalized graphene oxide

“…This released the target molecule to go to the next catalytic cycle. The authors achieved a detection limit of 5 pM DNA, which was significantly better than the ~1 nM limit without the signal amplification strategy [130].…”

Potential uses of G-quadruplex-forming aptamers

“…12). Other approaches for thrombin detection have recently been reviewed in a paper by Tucker et al (2012), and a novel approach for the optical detection of thrombin by multiplexed aptasensors using functionalized graphene oxide and logic gate operations have recently been reported by Liu et al (2012).…”

Exponential amplification of DNA with very low background using graphene oxide and single-stranded binding protein to suppress non-specific amplification

“…Based on this consideration, we describe a new technique for reducing the background signal in EXPAR by employing graphene oxide (GO), a water-dispersible modification of graphene that presents oxygen-containing functional groups [18][19][20][21][22]. GO has been used to harbor single-stranded templates (i.e., separating the enzyme from the template) in the detection of nucleic acids and proteins [23,20,24].…”