@article{moses_brewer_kraemer_fuierer_lowe_agbasi_sauthier_franzen_2007, title={Detection of DNA hybridization on indium tin oxide surfaces}, volume={125}, ISSN={["0925-4005"]}, DOI={10.1016/j.snb.2007.03.009}, abstractNote={Abstract Indium tin oxide (ITO) surfaces were modified with ssDNA by coupling oligonucleotides to a monolayer of 12-phosphonododecanoic acid (12-PDA) on ITO surfaces. This coupling involved the formation of an amide bond between the carboxylic acid moiety of 12-PDA to the amine group of a 5′-aminopropyl-labeled single strand of DNA. The self-assembled monolayer of 12-PDA and surface-attached oligonucleotides were characterized by X-ray photoelectron and reflectance FTIR spectroscopy. Detection of selective surface DNA hybridization was achieved by labeling the target ssDNA with gold nanoparticles. The presence of gold nanoparticles was probed using X-ray photoelectron spectroscopy, stripping voltammetry, atomic force microscopy, thermography, photoelectrochemistry (chronoamperometry) and cyclic voltammetry (CV). CV was used to successfully detect DNA hybridization for nanoparticle concentrations as low as 10 pM when using the gold nanoparticles bound to an ITO electrode as catalysts for the electrochemical oxidation of FeCl2. The studies described here provided the basis for surface attachment methodology for various electrochemical and thermographic sensing methods that use ITO thin films as a substrate.}, number={2}, journal={SENSORS AND ACTUATORS B-CHEMICAL}, author={Moses, Selina and Brewer, Scott H. and Kraemer, Stephan and Fuierer, Ryan R. and Lowe, Lisa B. and Agbasi, Chiamaka and Sauthier, Marc and Franzen, Stefan}, year={2007}, month={Aug}, pages={574–580} }
 @article{cerruti_sauthier_leonard_liu_duscher_feldheim_franzen_2006, title={Gold and silica-coated gold nanoparticles as thermographic labels for DNA detection}, volume={78}, ISSN={["1520-6882"]}, DOI={10.1021/ac0600555}, abstractNote={The infrared emissivity of Au and silica-coated Au nanoparticles (Au NPs) deposited on indium tin oxide substrates was investigated. NPs were irradiated with laser light at a frequency close to the Au plasmon resonance band, and the blackbody radiation emitted as a result was monitored with an IR camera equipped with an InAs array detector. The differences in temperature before and after laser irradiation were recorded (T-jumps) and were found to be directly proportional to the number of particles present on the slide and to the laser power used in the experiment. Coating Au NPs with silica increased the measured T-jumps 2−5 times, depending on the thickness of the silica shell. This was in agreement with the observation that silica has a much higher IR emissivity than Au. Both Au and silica-coated Au NPs were then tested as labels for thermographic DNA detection. Target DNA concentrations as low as 100 pM were recorded when Au NPs were used as labels and as low as 10 pM when silica-coated Au NPs were used.}, number={10}, journal={ANALYTICAL CHEMISTRY}, author={Cerruti, Marta G. and Sauthier, Marc and Leonard, Donovan and Liu, Dage and Duscher, Gerard and Feldheim, Daniel L. and Franzen, Stefan}, year={2006}, month={May}, pages={3282–3288} }
 @article{moses_brewer_lowe_lappi_gilvey_sauthier_tenent_feldheim_franzen_2004, title={Characterization of single- and double-stranded DNA on gold surfaces}, volume={20}, ISSN={["0743-7463"]}, DOI={10.1021/la0492815}, abstractNote={Single- and double-stranded deoxy ribonucleic acid (DNA) molecules attached to self-assembled monolayers (SAMs) on gold surfaces were characterized by a number of optical and electronic spectroscopic techniques. The DNA-modified gold surfaces were prepared through the self-assembly of 6-mercapto-1-hexanol and 5‘-C6H12SH -modified single-stranded DNA (ssDNA). Upon hybridization of the surface-bound probe ssDNA with its complimentary target, formation of double-stranded DNA (dsDNA) on the gold surface is observed and in a competing process, probe ssDNA is desorbed from the gold surface. The competition between hybridization of ssDNA with its complimentary target and ssDNA probe desorption from the gold surface has been investigated in this paper using X-ray photoelectron spectroscopy, chronocoulometry, fluorescence, and polarization modulation−infrared reflection absorption spectroscopy (PM−IRRAS). The formation of dsDNA on the surface was identified by PM−IRRAS by a dsDNA IR signature at ∼1678 cm-1 that was confirmed by density functional theory calculations of the nucleotides and the nucleotides' base pairs. The presence of dsDNA through the specific DNA hybridization was additionally confirmed by atomic force microscopy through colloidal gold nanoparticle labeling of the target ssDNA. Using these methods, strand loss was observed even for DNA hybridization performed at 25 °C for the DNA monolayers studied here consisting of attachment to the gold surfaces by single Au−S bonds. This finding has significant consequence for the application of SAM technology in the detection of oligonucleotide hybridization on gold surfaces.}, number={25}, journal={LANGMUIR}, author={Moses, S and Brewer, SH and Lowe, LB and Lappi, SE and Gilvey, LBG and Sauthier, M and Tenent, RC and Feldheim, DL and Franzen, S}, year={2004}, month={Dec}, pages={11134–11140} }
 @article{sauthier_carroll_gorman_franzen_2002, title={Nanoparticle Layers Assembled through DNA Hybridization:  Characterization and Optimization}, volume={18}, ISSN={["0743-7463"]}, DOI={10.1021/la0112763}, abstractNote={The hybridization of nanoparticle-labeled DNA targets to surface-attached DNA probes has been investigated. Scanning tunneling microscopy (STM) and Raman and Fourier transform infrared (FTIR) spectroscopy were used to elucidate surface morphology, coverage, and the presence of aggregates. The factors that affect surface coverage, such as probe density, labeled target concentration, and particle size, were systematically investigated by STM in order to determine the best set of experimental conditions allowing the formation of dense monolayers with a minimal number of surface defects for both 5(′1) nm and 10(′2) nm gold nanoparticle labels on the target strand. Grazing-angle FTIR spectroscopy demonstrates that DNA is largely oriented once the labeled targets hybridized to the probes. Raman microscopy was used to probe the surface for the presence of large aggregates that would give rise to large scattering signals. Both STM and optical experiments provide evidence that dense surface layers can be formed without extensive aggregation. Nonselective binding was shown to be a function of the target concentration and nanoparticle size. Propensity for both aggregation and nonspecific binding is greater for 10(′2) nm than for 5(′1) nm gold nanoparticles.}, number={5}, journal={Langmuir}, author={Sauthier, M.L. and Carroll, R.L. and Gorman, C.B. and Franzen, S.}, year={2002}, pages={1825–1830} }