Showing papers by "Sabahudin Hrapovic published in 2005"
TL;DR: This communication reveals new and unique optical properties with respect to enhanced fluorescence of gold nanorods as they elongate and a novel strategy for DNA hybridization studies based on monitoring the fluorescence intensity of gold Nanorods has been demonstrated.
113 citations
TL;DR: In this paper, a putrescine oxidase (POx) was used to construct an amperometric biosensor using a modified glassy carbon electrode, which exhibited current response within 10 µm with a detection limit of 500 µm.
Abstract: γ-Aminopropyltriethoxysilane (APTES)-induced solubilization of multi-wall carbon nanotube CNTs allowed for the modification of electrode surfaces. APTES also served as an immobilization matrix for putrescine oxidase (POx) to construct an amperometric biosensor. Although CNTs modified by APTES acted as semiconductors to reduce the exposed sensing surface, we reasoned that nanoscale “dendrites” of CNTS modified by APTES formed a network and projected outwards from the electrode surface and acted like bundled ultra-microelectrodes that allowed access to the active site and facilitated direct electron transfer to the immobilized enzyme. Our biosensor was able to efficiently monitor direct electroactivity of POx at the electrode surface. The putrescine biosensor prepared using the modified glassy carbon electrode exhibited current response within 10 s with a detection limit of 500 nM.
50 citations
TL;DR: A simple wet chemical method involving only ultrasonic processing in dilute ceric sulfate was used to functionalize carbon nanotubes, resulting in the destruction of SWCNTs to produce nonconducting amorphous carbon.
Abstract: A simple wet chemical method involving only ultrasonic processing in dilute ceric sulfate (CS) was used to functionalize carbon nanotubes (CNTs). Unexpectedly, single-walled and multiwalled carbon nanotubes (SWCNTs and MWCNTs) were cut, oxidized, and disintegrated by sonication in 0.1 N CS for 2-5 h. Transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction spectroscopy (XRD), Raman scattering, and photoacoustic Fourier transform infrared spectroscopy (FTIR) were used to probe wall damage during the chemical processing. Cyclic voltammetry and impedance spectroscopy were used to evaluate the conductivity of the CS-treated CNTs. This one-step process resulted in the destruction of SWCNTs to produce nonconducting amorphous carbon. MWCNTs were oxidized and converted to graphitic materials and amorphous carbon with retained conductivity.
45 citations
TL;DR: The modified electrode was good for at least 80 repeated measurements of 4 microM chlorobenzene with a storage stability of 1 month at room temperature and the deactivation of the electrode activity was associated with the loss of platinum nanoparticles from the nanocomposite structure.
Abstract: Pt−Zn porphyrin nanocomposites have been synthesized using zinc porphyrin and dihydrogen hexachloroplatinate in the presence of light and ascorbic acid. TEM and AFM imaging revealed that Pt nanoparticles with an average diameter of ∼3.5 nm were embedded within the Zn porphyrin matrix. The glassy carbon electrode was modified with Nafion-stabilized Pt−Zn porphyrin nanocomposites and used for dehalogenation of carbon tetrachloride, chloroform, pentachlorophenol, chlorobenzene, and hexachlorobenzene as five test models. The Pt−Zn porphyrin nanocomposite-modified electrode exhibited catalytic activity for the reduction of organohalides at −1.0 V versus Ag/AgCl. Raman signatures confirmed the dehalogenation of chlorobenzene by the nanocomposite-modified electrode. The above two aliphatic and three aromatic organohalides had detection limits of 0.5 μM with linearity up to 8 μM. The modified electrode was good for at least 80 repeated measurements of 4 μM chlorobenzene with a storage stability of 1 month at room...
8 citations