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Hu M.,University of Central Florida | Hu M.,Hewlett - Packard | Ghoshal A.,University of Central Florida | Marquez M.,YNano LLC | Kik P.G.,University of Central Florida
Journal of Physical Chemistry C | Year: 2010

We present an experimental study of the tunability of the silver nanoparticle localized plasmon resonance in close proximity to a gold film. Broad-band tuning of the silver particle plasmon resonance from blue wavelengths into the near-IR region can be achieved due to strong electromagnetic coupling between the nanoparticle and the metal film. When the thickness of a thin silica spacer layer between the metal nanoparticle and the metal film is altered, the resonance frequency shifts. Single particle spectroscopy of over 250 isolated silver nanoparticles revealed evidence for the excitation of both horizontal and vertical plasmon modes. Distinct resonance features observed in the scattering spectra were assigned to specific modes based on a dipole-dipole interaction model. The experimental results suggest that low-loss silver nanoparticles can be used in surface-enhanced spectroscopy studies throughout the entire visible spectrum. The use of frequency-tuned spherical metal nanoparticles on solid substrates could lead to thermally stable substrates for plasmon-enhanced sensing applications, including surface-enhanced Raman scattering and refractive index based biodetection methods. © 2010 American Chemical Society.


He P.,Texas A&M University | Kim H.,Texas A&M University | Luo D.,Texas A&M University | Marquez M.,YNano LLC | Cheng Z.,Texas A&M University
Applied Physics Letters | Year: 2010

Applications of electric field, using either dc or high-frequency ac field, have shown many advantages in emulsification. We further develop this technique by a detailed study on low-frequency ac electro-flow-focusing (EFF) microfluidic emulsification. Counter-intuitively, the droplet size variation is not monotonic with the electric field, in contrary to the dc-EFF emulsification. This phenomenon originates from a relaxation oscillation of flow rate through the Taylor cone. Particularly, a continuous droplet size decrease was obtained at the voltage ramp-up stage. This emulsification process was modeled in analog to the accumulation and release of charges in an RC electric circuit with an adjustable resistor. © 2010 American Institute of Physics.


Liu J.,Virginia Commonwealth University | Shen Z.,CAS Beijing National Laboratory for Molecular | Lee S.-H.,Dong - A University | Marquez M.,YNano LLC | McHugh M.A.,Virginia Commonwealth University
Journal of Supercritical Fluids | Year: 2010

Electrospinning is combined with the PCA (precipitation with a compressed fluid antisolvent) process (ES-PCA) to produce micron to submicron polymeric fibers with open-cell or hollow core morphology. CO2 is used as the compressed gas of choice and the impact of CO2 pressure (density) on fiber morphology is demonstrated for the poly(vinyl pyrrolidone) (PVP)-dichloromethane, PVP-ethanol, poly(vinylidenefluoride) (PVDF)-dimethylacetamide, and PVDF-dimethyl formamide systems. CO2, which is in excess for this process, rapidly extracts solvent from the surface of the liquid jet to form a vitrified polymer skin and also dissolves into the liquid jet and induces the polymer-solvent solution to phase separate. The ES-PCA technique has the advantage that fiber morphology can be easily controlled via pressure and pressures in excess of 100 bar are not needed to obtain a variety of different fiber morphologies. The fiber formation process correlates closely with the binary solvent-CO2 and ternary polymer-solvent-CO2 phase behavior. © 2010 Elsevier B.V. All rights reserved.


Shirk K.,Purdue University | Steiner C.,Purdue University | Kim J.W.,Hanyang University | Marquez M.,YNano LLC | Martinez C.J.,Purdue University
Langmuir | Year: 2013

We investigated the assembly of colloidal silica crystals inside double emulsion drops generated in microcapillary microfluidic devices. The double emulsions are composed of an aqueous suspension of monodisperse silica particles in the inner drop surrounded by a PDMS oil drop that acts as a semipermeable membrane for the diffusion of water into or out of the inner drop in the presence of an osmotic gradient. Imposing a high osmotic pressure in the continuous phase induces water diffusion out of the inner drop, increasing the silica volume fraction (φsilica) and leading to the formation of a spherical colloidal silica crystal. Silica suspensions with no salt or low salt concentration (<10-3 M) formed colloidal crystals with φsilica up to 0.68. Monodisperse spherical colloidal silica crystals with sizes ranging from 16 to 133 μm were generated by varying the device geometry, flow-rate ratios, and initial silica fraction. At salt concentrations > 10-3 M, the electrostatic repulsion is reduced, and crystallization is suppressed. Crystals were preserved in a hydrogel matrix or inside a silicone rubber shell. This study demonstrates a robust path for controlled colloidal assembly inside double emulsion drops. © 2013 American Chemical Society.


Patent
Ynano Llc | Date: 2010-03-17

A micro-scale artificial gland is disclosed in the form of an independent unit for promoting biological activity. The artificial gland includes cells formed in a membrane enclosing a reservoir. The reservoir is a bio-reactor capable of containing a product of activity of the cells. The reservoir comprises a gas, a liquid, and a gel and preferably also contains nanoparticles, a buffer, a surfactant, and, a gel precursor. The reservoir may also contain cells. Nanoparticles may also surround the artificial gland to form a protective coating. A variety of methods are disclosed for making the artificial gland by directed assembly of cells into the artificial micro-gland by gel, liquid or bubble templating. All involve coating the surface of gel, droplet or bubble with the living cells and the stabilizing the cells on the surface of gels, droplets or bubbles.


Trademark
Ynano Llc | Date: 2010-04-21

Yeast based biological preparations for medical use.


Trademark
Ynano Llc | Date: 2010-04-16

Biological preparations, namely, biochemical preparations for medical or veterinary use, namely, recombinant protein, enzymes, recombinant human enzymes, recombinant human enzymes in bacteria, algae, yeast, and eukaryotic cells, recombinant human drug-metabolizing enzymes; biological preparations, namely, reagents for use in development of monoclonal antibodies for medical use; biological preparations, namely, reagents for use in development of polyclonal antibodies for medical use; biochemical preparations containing enzymes for medical purposes; biochemical preparations containing enzymes for pharmaceutical purposes; biological preparations, namely, bacterial, algae, yeast, and eukaryotic cell membranes for medical use; biological preparations, namely, reagents in kit form for medical use.


Trademark
Ynano Llc | Date: 2010-05-27

Biological preparations for medical purposes.


Trademark
Ynano Llc | Date: 2010-05-27

Biological preparations, namely, biochemical preparations for medical or veterinary use, namely, recombinant protein, enzymes, recombinant human enzymes, recombinant human enzymes in bacteria, algae, yeast, and eukaryotic cells, recombinant human drug-metabolizing enzymes; biological preparations, namely, reagents for use in development of monoclonal antibodies for medical use; biological preparations, namely, reagents for use in development of polyclonal antibodies for medical use; biochemical preparations containing enzymes for medical purposes; biochemical preparations containing enzymes for pharmaceutical purposes; biological preparations, namely, bacterial, algae, yeast, and eukaryotic cell membranes for medical use; biological preparations, namely, reagents in kit form for medical use.


Trademark
Ynano Llc | Date: 2010-05-27

Biological preparations for medical purposes.

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