Dendritic amplification of DNA analysis by oligonucleotide-functionalized Au-nanoparticles

An OsII–Bisbipyridine–4‐Picolinic Acid Complex Mediates the Biocatalytic Growth of Au Nanoparticles: Optical Detection of Glucose and Acetylcholine Esterase Inhibition

“…Several control experiments and complementary experiments were performed to elucidate the mechanism of formation of the particles. Figure 1 curves c-g depicts the absorption spectra of the system upon the specific exclusion of the AuCl 4 À , in the absence of [Os-(bpy) 2 PyCO 2 H] 2 + , but in the presence of O 2 , upon the exclusion of citrate from the system, and upon the exclusion of glucose or GOx from the system, respectively. The control experiments reveal that in none of these systems Au NPs are formed and that the effective formation of the Au NPs depends on the presence of all of the components in the system.…”

“…The AuCl 4 À buffer solution includes an absorbance increase towards the UV region (see inset, curve b). Addition of AuCl 4 À to the Os II solution changes the structured Os II -complex spectrum; this indicates that AuCl 4 À oxidizes the Os II complex to the Os III species, [17] see Figure 1, inset, curve c. This set of experiments allows us to formulate the mechanism of Au NPs growth in the composite system (see Scheme 1). The Os II -complex 1, acts as electron-transfer mediator for the catalytic growth of the particles.…”

“…In the absence of the Os II complex, the O 2 -mediated oxidation of glucose by GOx proceeds to yield H 2 O 2 . Previous studies have suggested that H 2 O 2 may act as a reducing agent for AuCl 4 À to form Au NPs. [16] Nonetheless, under the present experimental conditions the H 2 O 2 -stimulated growth of the particles is excluded (cf.…”

“…[3] Similarly, nucleic acid-modified Au NPs were used as "weight labels" for the microgravimetric quartz crystal microbalance analysis of DNA. [4] The catalytic properties of metal NPs towards the deposition of metals were extensively used for the amplified biosensing of antigen-antibody complexes, [5] DNA hybridization processes [6] and aptamerprotein binding. [7] For example, the catalytic enlargement of Au NP-labeled DNA complexes between electrodes was used for the biosensing of DNA by conductivity measurements.…”

Amplified Surface Plasmon Resonance Based DNA Biosensors, Aptasensors, and Hg2+ Sensors Using Hemin/G‐Quadruplexes and Au Nanoparticles

“…Among the different sensing platforms, numerous studies have implemented metal nanoparticles in the development of optical, [4] electrical, [5] field-effect transistor, [6] or microgravimetric nucleic acids-based biosensors. [7] Specifically, the development of amplified DNA-based sensor systems has gained substantial interest that was directed toward the development of sensitive detection schemes. [8] Enzymes [9] or metal nanoparticles [10] were used as catalytic labels for amplifying DNA-sensing or aptamer-sensing events.…”