Biomedical subjects

J Anthony Smith

Publications and source records attributed to J Anthony Smith.

4 recordsLinked to original sources

PubMed2005

Gold-polyaniline composite. Part I. Moving electrochemical interface.

The controlled growth of gold nanoclusters in polyaniline is predicated by the ability of PANI to switch from conducting to insulating form and by the fact that imine nitrogens form a strong complex with chloroaurate anions. The principal technique used in this study has been chronopotentiometric stripping. The chronopotentiograms indicate that the electrochemical interface for the Pt/Au/polyaniline/electrolyte shifts back and forth from the solution/PANI interface to Au/PANI interface. By adjusting experimental conditions the size and the size distribution of Au clusters can be controlled.

Aniline Compounds↗

PubMed2005

Gold-polyaniline composites. Part II. Effects of nanometer sized particles.

The amount of electronic charge transferred between gold particles and polyaniline depends not only on the electron affinity of the two materials but also on the size of the gold particles. As measured by X-ray photoelectron spectroscopy, for particles < approximately 5 nm the binding energy of the electrons is size dependent. This "nano-effect" has its origin in the electrostatics of particles. It is demonstrated as a measurable shift of the binding energy of the Au(4f7/2) photoelectrons emitted from Au particles embedded in a polyaniline matrix. Gold nanoparticle size was evaluated by high resolution transmission electron microscopy.

Aniline Compounds↗

PubMed2004

Plastic tip arrays for force spectroscopy.

The mechanical stability and viability of molecules investigated with the atomic force microscope (AFM) continue to be limiting factors in the duration of force spectroscopy measurements. In an effort to circumvent this problem, we have fabricated an all-plastic array of over 30 000 tips with dimensions similar to common AFM probes using silicon micromolding techniques. This approach enables rapid fabrication of tip arrays with improved properties, as compared to tip arrays made entirely of silicon.

Gold↗

PubMed2004

Acridones and quinacridones: novel fluorophores for fluorescence lifetime studies.

Two new families of fluorescent probe, acridones and quinacridones, whose fluorescence lifetime can be altered to produce a range of lifetimes from 3 ns to 25 ns are described. Both families of fluorophore have fluorescence lifetimes which are unaffected by pH in the range of 5 to 9 and show a marked resistance to photobleaching. The probes have been modified to allow them to be attached to biomolecules and the labelling of a neuropeptide (substance P) is described. The labelled peptides have the same fluorescence lifetime as the free fluorophore. Quinacridone, with an emission around 550 nm offers a long fluorescence lifetime, photostable alternative to fluorescein.

Acridines↗