Shrink-induced silica multiscale structures for enhanced fluorescence from DNA microarrays.

We describe a manufacturable and scalable method for fabrication of multiscale wrinkled silica (SiO2) structures on shrink-wrap film to enhance fluorescence signals in DNA fluorescence microarrays. We are able to enhance the fluorescence signal of hybridized DNA by more than 120 fold relative to a planar glass slide. Notably, our substrate has improved detection sensitivity (280 pM) relative to planar glass slide (11 nM).

Single-nanoparticle near-infrared surface plasmon resonance microscopy for real-time measurements of DNA hybridization adsorption.

A novel 814 nm near-infrared surface plasmon resonance (SPR) microscope is used for the real-time detection of the sequence-selective hybridization adsorption of single DNA-functionalized gold nanoparticles. The objective-coupled, high numerical aperture SPR microscope is capable of imaging in situ the adsorption of single polystyrene and gold particles with diameters ranging from 450 to 20 nm onto a 90 μm × 70 μm area of a gold thin film with a time resolution of approximately 1-3 s. Initial real-time SPR imaging (SPRI) measurements were performed to detect the accumulation of 40 nm gold nanoparticles for 10 min onto a gold thin film functionalized with a 100% complementary DNA surface at concentrations from 5 pM to 100 fM by counting individual particle binding events.

Electrodeposition of polydopamine thin films for DNA patterning and microarrays.

The controlled electrodeposition of functional polydopamine (PDA) thin films from aqueous dopamine solutions is demonstrated with a combination of electrochemistry, atomic force microscopy (AFM), and surface plasmon resonance (SPR) measurements. PDA micropatterns are then fabricated by electrodeposition on micrometer length scale gold electrodes and used for attaching amino-modified single-stranded DNA (ssDNA). After hybridization with fluorescently labeled ssDNA, the fluorescence microscopy characterization reveals that: (i) PDA can be toposelectively deposited at the microscale and (ii) electrochemically deposited PDA can be functionalized with amino-terminated ssDNA using the same chemistry as that for spontaneously deposited PDA.

Fabrication of DNA microarrays on polydopamine-modified gold thin films for SPR imaging measurements.

Polydopamine (PDA) films were fabricated on thin film gold substrates in a single-step polymerization-deposition process from dopamine solutions and then employed in the construction of robust DNA microarrays for the ultrasensitive detection of biomolecules with nanoparticle-enhanced surface plasmon resonance (SPR) imaging. PDA multilayers with thicknesses varying from 1 to 5 nm were characterized with a combination of scanning angle SPR and AFM experiments, and 1.3 ± 0.

Furan hydrogenation over Pt(111) and Pt(100) single-crystal surfaces and Pt nanoparticles from 1 to 7 nm: a kinetic and sum frequency generation vibrational spectroscopy study.

Sum frequency generation surface vibrational spectroscopy and kinetic measurements using gas chromatography have been used to systematically study the adsorption and hydrogenation of furan over Pt(111) and Pt(100) single-crystal surfaces and size-controlled 1.0-nm, 3.5-nm and 7.