Graphene oxide and DNA aptamer based sub-nanomolar potassium detecting optical nanosensor

Abstract

Quantum-dot (QD) based nanosensors are frequently used by researchers to detect small molecules, ions and different biomolecules. In this article, we present a sensor complex/system comprised of deoxyribonucleic acid (DNA) aptamer, gold nanoparticle and semiconductor QD, attached to a graphene oxide (GO) flake for detection of potassium. As reported herein, it is demonstrated that QD-aptamer-quencher nanosensor functions even when tethered to GO, opening the way to future applications where sensing can be accomplished simultaneously with other previously demonstrated applications of GO such as serving as a nanocarrier for drug delivery. Herein, it is demonstrated that the DNA based thrombin binding aptamer used in this study undergoes the conformational change needed for sensing even when the nanosensor complex is anchored to the GO. Analysis with the Hill equation indicates the interaction between aptamer and potassium follows sigmoidal Hill kinetics. It is found that the quenching efficiency of the optical sensor is linear with the logarithm of concentration from 1 pM to 100 nM and decreases for higher concentration due to unavailability of aptamer binding sites. Such a simple and sensitive optical aptasensor with minimum detection capability of 1.96 pM for potassium ion can also be employed in-vitro detection of different physiological ions, pathogens and disease detection methods.

Homogenous Magneto-Fluorescent Nanosensor for Tumor-Derived Exosome Isolation and Analysis

“…Nanosensor provides a homogeneous platform for low-cost and sensitive proteins measurement, which is a promising solution for the POCT analysis toward tumor-derived exosomal proteins. For example, graphene oxide (GO), a novel two-dimensional carbon nanomaterial with excellent water solubility, strong adsorption capacity, and fluorescent quenching ability, was widely employed in high selective aptamer-based fluorescence nanosensors. , However, even if the aptamer has advantages including high affinity and excellent specificity, they provide limited signal output by 1:1 combining with target proteins. Hence, it is necessary to improve the detection sensitivity through signal amplification strategies.…”

Development of a ssDNA aptamer system with reduced graphene oxide (rGO) to detect nonylphenol ethoxylate in domestic detergent

“…Brillouin zone 16 and a nearly constant optical absorption; thus, optically excited species can be quenched by resonance energy transfer via excitation of electron-hole pairs in the graphene. [17][18][19] Herein, we describe the identification and development of a specific aptamer sequence to NP12 which is a kind of NPEs. In short, we screened aptamers with rGO to screen the aptamer against an immobilized target and characterized positive sequences with rGO and gold nanoparticles (AuNP).…”

“…Graphene was used as a substrate for the nonspecific adsorption of a fluorescent dye‐labeled aptamer for noncovalent assembly. Graphene has a linear band dispersion around the corners of its Brillouin zone and a nearly constant optical absorption; thus, optically excited species can be quenched by resonance energy transfer via excitation of electron‐hole pairs in the graphene …”

Development of a Novel ssDNA Sequence for a Glycated Human Serum Albumin and Construction of a Simple Aptasensor System Based on Reduced Graphene Oxide (rGO)

“…In this work, graphene was also used as a substrate for nonspecific adsorption of fluorescent dye-labeled aptamers in SELEX process. Graphene has a linear band dispersion around the corners of its Brillouin zone (BZ) and a nearly constant optical absorption; thus, optically excited species can be quenched by resonance energy transfer via excitation of electron-hole pairs in the graphene [ 40 , 41 , 42 , 43 , 44 ]. Besides, using this principle, rGO system was used to characterize binding affinity and specificity of aptamers against the target as well.…”