R. P. Andres

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This paper reports the creation of Au nanoparticles (AuNP) that are soluble in aqueous solution over a broad range of pH and ionic strength values and that are capable of selective uptake by folate receptor positive (FR+) cancer cells. A novel poly(ethylene glycol) (PEG) construct with thioctic acid and folic acid coupled on opposite ends of the polymer(More)
The weak binding of preformed metallic clusters to atomically smooth substrates has presented an impediment to the study of supported nanometer-size clusters using scanning probe techniques. The sweeping of supported clusters on flat substrates by a scanning probe tip has been identified as a problem. Unless special precautions are taken, only those(More)
By using as sources supersonic jets of hydrogen or helium containing small concentrations of heavier molecules we have been able to obtain molecular beams with kinetic energies of the heavy molecules well into the range above I electron volt. A variety of molecules have been successfully accelerated. Intensities of 10(16) to 10(17) heavy molecules per(More)
We review current research on the electronic properties of nanoscale metallic islands and clusters deposited on semiconductor substrates. Reported results for a number of nanoscale metal-semiconductor systems are summarized in terms of their fabrication and characterization. In addition to the issues faced in large-area metal-semiconductor systems,(More)
Field-ion microscopy ~FIM! is used to resolve the atomic structure and orientation of individual nanometersize Au clusters supported on sharp tips of W, Pt, and a Pt/Ir alloy. The FIM images from a single cluster illustrate that the technique is capable of providing atomically resolved images of supported nanometer-size clusters in an ultrahigh vacuum(More)
Monolayers of resorcinarene tetraene 1 on gold nanoclusters could be crosslinked by olefin metathesis into a nondesorptive shell. Crosslinking conditions were optimized by monitoring olefin metathesis of 1 by H NMR spectroscopy and obtaining empirical rate constants. Gel permeation chromatography (GPC) was found to be a useful tool for evaluating the(More)
The development and characterization of high-performance nanocontacts to n-GaAs are reported. The nanocontacts can be made to both undoped and p-doped low-temperature-grown GaAs ~LTG:GaAs! cap layers. The geometry of the nanocontact is well characterized and requires the deposition of a 4 nm single-crystalline Au cluster onto an ohmic contact structure(More)
Self-assembly (‘building’) approaches can provide well-controlled structures and assemblies at the nanometer scale, but typically do not provide the specific structures or functionalities required for robust nanoelectronic circuits. One approach to realize high-density nanoelectronic circuits is to combine self-assembly techniques with more conventional(More)
A new strategy for stabilizing inorganic nanoparticles in nonpolar solutions is described. Resorcinarenes 1-3 were synthesized and evaluated as surfactants because of their large concave headgroups with multiple contact sites. Au nanoparticles ranging from 3-20 nm in diameter were generated in the vapor phase and dispersed into dilute hydrocarbon solutions(More)