A Novel DNA Nanosensor Based on CdSe/ZnS Quantum Dots and Synthesized Fe3O4 Magnetic Nanoparticles

Abstract

Although nanoparticle-enhanced biosensors have been extensively researched, few studies have systematically characterized the roles of nanoparticles in enhancing biosensor functionality. This paper describes a successful new method in which DNA binds directly to iron oxide nanoparticles for use in an optical biosensor. A wide variety of nanoparticles with different properties have found broad application in biosensors because their small physical size presents unique chemical, physical, and electronic properties that are different from those of bulk materials. Of all nanoparticles, magnetic nanoparticles are proving to be a versatile tool, an excellent case in point being in DNA bioassays, where magnetic nanoparticles are often used for optimization of the hybridization and separation of target DNA. A critical step in the successful construction of a DNA biosensor is the efficient attachment of biomolecules to the surface of magnetic nanoparticles. To date, most methods of synthesizing these nanoparticles have led to the formation of hydrophobic particles that require additional surface modifications. As a result, the surface to volume ratio decreases and nonspecific bindings may occur so that the sensitivity and efficiency of the device deteriorates. A new method of large-scale synthesis of iron oxide (Fe 3 O 4 ) OPEN ACCESSMolecules 2014, 19 4356 nanoparticles which results in the magnetite particles being in aqueous phase, was employed in this study. Small modifications were applied to design an optical DNA nanosensor based on sandwich hybridization. Characterization of the synthesized particles was carried out using a variety of techniques and CdSe/ZnS core-shell quantum dots were used as the reporter markers in a spectrofluorophotometer. We showed conclusively that DNA binds to the surface of ironoxide nanoparticles without further surface modifications and that these magnetic nanoparticles can be efficiently utilized as biomolecule carriers in biosensing devices.

An Overview of the Oil Palm Industry: Challenges and Some Emerging Opportunities for Nanotechnology Development

“…Other work had also been conducted by extracting the DNA of the infected seedlings. Hushiarian et al reported that the detection could be performed using magnetic nanoparticles as immobilized DNA via amide linkages [138,139]. Meanwhile, Dutse et al worked on ruthenium complexes as redox indicators and helped in the intercalation of DNA [140,141].…”

Metal Oxide Nanoparticles in Electroanalysis

“…Many methods of immobilization can be employed to maximize the number of the capture probes on the surface of the electrode. Some examples include using the Au‐S bond with gold nanoparticles 93–95, using biotin‐avidin interaction 96, amide linkage through carboxylic groups on the surface of nanoparticles 97 or through silane reactions to form aldehyde groups on the electrode surface 98. DNA detection is then performed after the target DNA is hybridized to the surface‐immobilized capture probes.…”

“…Not only can metal oxide nanoparticles be employed to improve the sensitivity of DNA detection through the increased surface area of metal oxide nanoparticles for the immobilization of capture probes and the function of certain metal oxide nanoparticles as electrical conductors or semiconductors, magnetic nanoparticles can also be employed for specific detection of magnetic particle‐bound DNA, such as the removal of non‐hybridized DNA before electrochemical detection 97, 104. Pal et al.…”

Detection of Quinoline in G. boninense-Infected Plants Using Functionalized Multi-Walled Carbon Nanotubes: A Field Study

“…Some methods have included polymerase chain reaction (PCR) amplification [ 12 , 13 , 14 ] but have encountered challenges of gene bank aberrations resulting from sequencing [ 2 , 13 , 15 ]. Other recent methods have used electrochemical sensors and have involved the complex process of extracting DNA from the infected part of a tree [ 16 , 17 , 18 , 19 ]. The disease has also been detected via hyperspectral data and imagery techniques [ 2 , 20 , 21 ] with the attendant problems of tying to observe palm leaves coupled at the top of palm canopies.…”