We demonstrate a convenient and cost-effective chemical approach for fabricating highly ordered Au nanoparticle arrays with sub-10-nm interparticle gaps. Near-field enhancements inside the interparticle gaps create uniform periodic arrays of well-defined "hot spots" exploitable for large surface-enhanced Raman spectroscopy (SERS) enhancements. A cetyltrimethylammonium bromide (CTAB) bilayer sur...

The structure of the recently synthesized mercaptosuccinic acid-protected Au6Ag7(SR)10 cluster has been elucidated by a DFT approach, following an isoelectronic substitution of seven Au atoms by Ag atoms on the [Au13(SR)10](+) cluster. After a systematic search for the lowest-energy isomers, it is demonstrated that its structure comprises one octahedral-like Ag6 core covered by two monoatomic d...

A stable, Ag55 cluster protected with 4-(tert-butyl)benzyl mercaptan (BBSH) was synthesized which exhibits two prominent absorption bands with maxima at 2.25 and 2.81 eV. A molecular ion peak at m/z 11 500 ± 20 in matrix assisted laser desorption ionization mass spectrum (MALDI MS), assigned to Ag55(BBS)31 was observed. Electrospray ionization (ESI MS) shows a prominent trication along with hig...

Eggshell membranes (ESMs) provide a unique, disulfide bond-rich surface. Thioglycolate reduction was used to generate thiol (-SH) groups on the ESM surface by S-S bond cleavage. The thiol-bearing ESMs (TESMs) were characterized by scanning electron microscopy and Raman spectroscopy. The fibrous network structure of the ESM is retained in the TESMs. TESMs adsorb both Se(IV) and Se(VI) but by dif...

The sensing mechanism of DNA with carbon nanotube– field effect transistor sensors is investigated by firstprinciples electronic structure calculations. We have investigated the interaction of individual DNA nucleobases (especially guanine and cytosine) with single walled carbon nanotubes (SWNTs), and compared the binding energies of various configurations including π-stacking and direct bondin...

Flexible, charged Pd nanosheets were prepared by using short chain thiolated carboxylic acids and amines. They could wrap around amine or hydroxyl functionalized micron-sized spheres driven by electrostatic interactions. Upon incubation with HepG2 cells, the positively charged cysteamine (CA) functionalized Pd nanosheets exhibited a much higher cytotoxicity, showing more than 80% cell death at ...

We characterize the room-temperature adsorption of single-stranded DNA homo-oligonucleotides from solution onto polycrystalline Au films, including competitive adsorption between all possible pairs of unmodified oligomers. Fourier transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy analysis of the resulting films shows that oligonucleotides adsorb with a strongly base-dependent...

A surface plasmon resonance sensor for Mycobacterium tuberculosis (MTB) deoxyribonucleic acid (DNA) is developed using repeatable telecommunication wavelength modulation based on optical fiber communications laser wavelength and stability. MTB DNA concentrations of 1 μg/mL and 10 μg/mL were successfully demonstrated to have the same spectral half-width in the dip for optimum coupling. The sensi...