Plasmonic Nanostructures for Solar and Biological Application

The electromagnetic absorption properties of plasmonic nanostructures were utilized to develop mesoscopic sites for highly efficient photothermal generation steam, SERS biosensing, and light-triggered cellular delivery uptake. Plasmonic nanostructures embedded in common thermal solutions produces vapor without the requirement of heating the fluid volume. When particles are dispersed in water at ambient temperature, energy is directed primarily to vaporization of water into steam, with a much smaller fraction resulting in heating of the fluid. Solar illuminated aqueous nanoparticle solution can drive water-ethanol distillation, yielding fractions significantly richer in ethanol content than simple thermal distillation and also produced saturated steam destroying Geobacillus stearothermophilus bacteria in a compact solar powered autoclave. Subwavelength biosensing sites were developed using the plasmonic properties of gold nanoshells to investigate the properties of aptamer (DNA) target complexes. Nanoshells are tunable core-shell nanoparticles whose resonant absorption and scattering properties are dependent on core/shell thickness ratio. Nanoshells were used to develop a label free detection method using SERS to monitor conformational change induced by aptamer target binding. The conformational changes to the aptamers induced by target binding were probed by monitoring the aptamer SERS spectra reproducibility. Furthermore, nanoshells can serve as a nonviral light-controlled delivery vector for the precise temporal and spatial control of molecular delivery in vitro. The drug delivery concept using plasmonic vectors was shown using a monolayer of ds-DNA attached to the nanoshell surface and the small molecular “parcel” intercalated inside ds-DNA loops. DAPI, a fluorescent dye, was used as the molecular parcel to visualize the release process in living cells. Upon laser illumination at the absorption resonance the nanoshell converts photon energy into heat producing a local temperature gradient that induces DNA dehybridization, releasing the intercalated molecules

Plasmonic Gadolinium Oxide Nanomatryoshkas: Bifunctional Magnetic Resonance Imaging Enhancers for Photothermal Cancer Therapy

Nanoparticle-assisted laser-induced photothermal therapy (PTT) is a promising method for cancer treatment; yet, visualization of nanoparticle uptake and photothermal response remain a critical challenge. Here, we report a magnetic resonance imaging-active nanomatryoshka (Gd2O3-NM), a multilayered (Au core/Gd2O3 shell/Au shell) sub-100 nm nanoparticle capable of combining T1 MRI contrast with PTT. This bifunctional nanoparticle demonstrates an r1 of 1.28 × 108 mM-1 s-1, an MRI contrast enhancement per nanoparticle sufficient for T1 imaging in addition to tumor ablation. Gd2O3-NM also shows excellent stability in an acidic environment, retaining 99% of the internal Gd(3). This report details the synthesis and characterization of a promising system for combined theranostic nanoparticle tracking and PTT

Waste remediation

A system including a steam generation system and a chamber. The steam generation system includes a complex and the steam generation system is configured to receive water, concentrate electromagnetic (EM) radiation received from an EM radiation source, apply the EM radiation to the complex, where the complex absorbs the EM radiation to generate heat, and transform, using the heat generated by the complex, the water to steam. The chamber is configured to receive the steam and an object, wherein the object is of medical waste, medical equipment, fabric, and fecal matter

Cooling systems and hybrid A/C systems using an electromagnetic radiation-absorbing complex

A method for powering a cooling unit. The method including applying electromagnetic (EM) radiation to a complex, where the complex absorbs the EM radiation to generate heat, transforming, using the heat generated by the complex, a fluid to vapor, and sending the vapor from the vessel to a turbine coupled to a generator by a shaft, where the vapor causes the turbine to rotate, which turns the shaft and causes the generator to generate the electric power, wherein the electric powers supplements the power needed to power the cooling unit

MRI Active Gold Nanoshells for MRI Guided Localized Photothermal Therapy

https://openworks.mdanderson.org/sumexp21/1252/thumbnail.jp

Evolution of light-induced vapor generation at a liquid-immersed metallic nanoparticle

When an Au nanoparticle in a liquid medium is illuminated with resonant light of sufficient intensity, a nanometer scale envelope of vapor -a “nanobubble”- surrounding the particle, is formed. This is the nanoscale onset of the well-known process of liquid boiling, occurring at a single nanoparticle nucleation site, resulting from the photothermal response of the nanoparticle. Here we examine bubble formation at an individual metallic nanoparticle in detail. Incipient nanobubble formation is observed by monitoring the plasmon resonance shift of an individual, illuminated Au nanoparticle, when its local environment changes from liquid to vapor. The temperature on the nanoparticle surface is monitored during this process, where a dramatic temperature jump is observed as the nanoscale vapor layer thermally decouples the nanoparticle from the surrounding liquid. By increasing the intensity of the incident light or decreasing the interparticle separation, we observe the formation of micron sized bubbles resulting from the coalescence of nanoparticle-“bound” vapor envelopes. These studies provide the first direct and quantitative analysis of the evolution of light-induced steam generation by nanoparticles from the nanoscale to the macroscale, a process that is of fundamental interest for a growing number of applications

Nanoparticle-Mediated, Light-Induced Phase Separations

Nanoparticles that both absorb and scatter light, when dispersed in a liquid, absorb optical energy and heat a reduced fluid volume due to the combination of multiple scattering and optical absorption. This can induce a localized liquid–vapor phase change within the reduced volume without the requirement of heating the entire fluid. For binary liquid mixtures, this process results in vaporization of the more volatile component of the mixture. When subsequently condensed, these two steps of vaporization and condensation constitute a distillation process mediated by nanoparticles and driven by optical illumination. Because it does not require the heating of a large volume of fluid, this process requires substantially less energy than traditional distillation using thermal sources. We investigated nanoparticle-mediated, light-induced distillation of ethanol-H₂O and 1-propanol-H₂O mixtures, using Au–SiO₂ nanoshells as the absorber-scatterer nanoparticle and nanoparticle-resonant laser irradiation to drive the process. For ethanol-H₂O mixtures, the mole fraction of ethanol obtained in the light-induced process is substantially higher than that obtained by conventional thermal distillation, essentially removing the ethanol-H₂O azeotrope that limits conventional distillation. In contrast, for 1-propanol-H₂O mixtures the distillate properties resulting from light-induced distillation were very similar to those obtained by thermal distillation. In the 1-propanol-H₂O system, a nanoparticle-mediated, light-induced liquid–liquid phase separation was also observed