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Surface plasmons

Liuyang Zhang, Diwen Shi, Tang Jiao Huang, Ruizhe Huang, Hao Gong
By decorating nickel copper hydroxide (NCH) with Ag nanowires (Ag NWs), a 1.7 fold enhancement in areal capacitance (5.4 F cm(-2)) and a 1.8 fold increment in gravimetric capacitance (3182 F g(-1)) under light illumination were achieved. The improved supercapacitor performances of the composites under visible-light illumination were demonstrated and a reasonable explanation for this newly-discovered phenomenon was proposed. The plasmonic effect of Ag NWs was demonstrated by hot-electron generation. The decorated Ag NWs served as a stimulus for redox reactions...
November 17, 2017: Nanoscale
Patrick J Straney, Nathan A Diemler, Ashley M Smith, Zachary E Eddinger, Matthew S Gilliam, Jill E Millstone
We report the use of gold nanoparticle surface chemistry as a tool for site-selective noble metal deposition onto colloidal gold nanoparticle substrates. Specifically, we demonstrate that partial passivation of the gold nanoparticle surface using thiolated ligands can induce a transition from linear palladium island deposition to growth of palladium selectively at plasmonic hotspots on the edges or vertices of the underlying particle substrate. Further, we demonstrate the broader applicability of this approach with respect to substrate morphology (e...
November 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Matthew J Eibling, Christopher M MacDermaid, Zhaoxia Qian, Christopher J Lanci, So-Jung Park, Jeffery G Saven
Functionalization of nanoparticles with biopolymers has yielded a wide range of structured and responsive hybrid materials. DNA provides the ability to program length and recognition using complementary oligonucleotide sequences. Nature more often leverages the versatility of proteins, however, where structure, assembly, and recognition are more subtle to engineer. Herein, a protein was computationally designed to present multiple Zn(2+) coordination sites and cooperatively self-associate to form an antiparallel helical homodimer...
November 17, 2017: Journal of the American Chemical Society
J B Pendry, Paloma Arroyo Huidobro, Yu Luo, Emanuele Galiffi
In advanced field theories, there can be more than four dimensions to space, the excess dimensions described as compacted and unobservable on everyday length scales. We report a simple model, unconnected to field theory, for a compacted dimension realized in a metallic metasurface periodically structured in the form of a grating comprising a series of singularities. An extra dimension of the grating is hidden, and the surface plasmon excitations, though localized at the surface, are characterized by three wave vectors rather than the two of typical two-dimensional metal grating...
November 17, 2017: Science
Yong'an Tang, Tao Yang, Qiaoli Wang, Xiaoyan Lv, Xue Song, Hengte Ke, Zhengqing Guo, Xiaoqing Huang, Jun Hu, Zifu Li, Peng Yang, Xiangliang Yang, Huabing Chen
Photoactive noble metal nanoparticles are of increasing importance toward personalized cancer therapy in the field of precision nanomedicine. A critical challenge remains in the exploration of clinically potential noble metal nanoparticles for highly efficient cancer theranostics. Here, we introduce albumin-coordinated assembly of clearable Pt nanodots (Pt-NDs) with monodisperse nanostructure as high-performance theranostic agents for imaging-guided photothermal tumor ablation. We precisely manipulate the reduction and growth of tetravalent Pt ions into ultrasmall nanodots through albumin-directed growth kinetics, thereby leading to the synthesis of monodisperse 6...
October 20, 2017: Biomaterials
Preston R Huft, Joshua D Kolbow, Jonathan T Thweatt, Nathan C Lindquist
We demonstrate dynamic trapping and manipulation of nanoparticles with plasmonic holograms. By tailoring the illumination pattern of an incident light beam with a computer-controlled spatial light modulator, constructive and destructive interference of plasmon waves create a focused hotspot that can be moved across a surface. Specifically, a computer-generated hologram illuminating the perimeter of a silver Bull's Eye nanostructure generates surface plasmons that propagate towards the center. Shifting the phase of the plasmon waves as a function of space gives complete control over the location of the focus...
November 16, 2017: Nano Letters
Xueke Duan, Juanjuan Ren, Fan Zhang, He Hao, Guowei Lu, Qihuang Gong, Ying Gu
Combining the advantages of both gap surface plasmons and evanescent waves, we demonstrate simultaneously large Purcell enhancement and efficient one- dimensional collection of photons at subwavelength scale in the coupled nanowire- nanorod system. The spontaneous emission can be enhanced by thousands of times based on the excitation of gap surface plasmons with strongly localized electromagnetic field. Emitted photons are directly collected by subwavelength-confined evanescent modes and guided along the nanowire...
November 16, 2017: Nanotechnology
Weina Zhang, Juan Li, Hongxiang Lei, Baojun Li
By introducing an 18 nm-thick Au nanofilm, selective enhancement of green emission from Lanthanide-doped (β-NaYF4: Yb3+/Er3+) upconversion nanoparticles (UCNPs) is demonstrated. The Au nanofilm is deposited on a microfiber surface by the sputtering method and then covered with the UCNPs. The plasma on the surface of the Au nanofilm can be excited by launching a 980 nm-wavelength laser beam into the microfiber, resulting in an enhancement of the local electric field and a strong thermal effect. A 36-fold luminescence intensity enhancement of the UCNPs at 523 nm is observed with no obvious reduction in the photostability of the UCNPs...
November 16, 2017: ACS Applied Materials & Interfaces
Beibei Liu, Shuo Wang, Karl Aston, Kevin J Koeller, Shahrzad Fanny Hakami Kermani, Carlos H Castañeda, M José Scuderi, Rensheng Luo, James K Bashkin, W David Wilson
Minor-groove binding hairpin polyamides (PAs) bind specific DNA sequences. Synthetic modifications can improve PA-DNA binding affinity and include flexible modules, such as β-alanine (β) motifs to replace pyrroles (Py), and increasing compound charge using N-terminal cationic substituents. To better understand the variations in kinetics and affinities caused by these modifications on PA-DNA interactions, a comprehensive set of PAs with different numbers and positions of β and different types of N-cationic groups was systematically designed and synthesized to bind their cognate sequence, the λB motif...
November 16, 2017: Organic & Biomolecular Chemistry
A K Bhunia, T Kamilya, S Saha
In this paper, we have used spectroscopic and electron microscopic analysis to monitor the time evolution of the silver nanoparticles (Ag NP)-human hemoglobin (Hb) corona formation and to characterize the interaction of the Ag NPs with Hb. The time constants for surface plasmon resonance binding and reorganization are found to be 9.51 and 118.48 min, respectively. The drop of surface charge and the increase of the hydrodynamic diameter indicated the corona of Hb on the Ag NP surface. The auto correlation function is found to broaden with the increasing time of the corona formation...
2017: Nano Convergence
Manu M Joseph, Jyothi B Nair, Kaustabh Kumar Maiti, Sreelekha Therakathinal T
Biopolymer capped gold nanoparticles (AuNPs) were perceived for tracing biodistribution in a solid tumor mice through surface-enhanced Raman scattering (SERS) fingerprinting. In this strategy, a robust and ecofriendly green chemistry approach was adopted to construct galactoxyloglucan (PST001) endowed AuNPs (PST-GNPs) with cancer-cell-selective toxic nature and excellent biocompatibility. Plasmonically enhanced light scattering properties facilitated PST-GNPs to be a superior SERS substrate with high Raman signal enhancement...
November 15, 2017: Biomacromolecules
Zhijun Li, Kim A Munro, Iraklii I Ebralidze, Mina R Narouz, J Daniel Padmos, Hongxia Hao, Cathleen M Crudden, J Hugh Horton
Surface plasmon resonance (SPR)-based biosensing is a powerful tool to study the recognition processes between biomole-cules in real-time without need for labels. The use of thiol chemistry is a critical component in surface functionalization of various SPR biosensor surfaces on gold. However, its use is hampered by the high propensity for oxidation of the gold-thiol linkage even in ambient atmosphere, resulting in a short lifetime of SPR sensor chips unless strict precautions are taken. Herein, we describe an approach to overcome this limitation by employing highly robust self-assembled monolayers (SAMs) of alkylated N-heterocyclic carbenes (NHCs) on gold...
November 15, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Lars Friedrich, Petra Kornberger, Claudia T Mendler, Gabriele Multhoff, Markus Schwaiger, Arne Skerra
We describe the selection of Anticalins against a common tumour surface antigen, human Hsp70, using functional display on live E. coli cells as fusion with a truncated EspP autotransporter. While found intracellularly in normal cells, Hsp70 is frequently exposed in a membrane-bound state on the surface of tumour cells and, even more pronounced, in metastases or after radiochemotherapy. Employing a recombinant Hsp70 fragment comprising residues 383-548 as target, Anticalins were selected from a naive bacterial library...
November 27, 2017: Biological Chemistry
Yang Li, Meng Kang, Junjun Shi, Ke Wu, Shunping Zhang, Hongxing Xu
Coherently adding up signal wave from different locations are a prerequisite for realizing efficient nonlinear optical processes in traditional optical configurations. While nonlinear optical processes in plasmonic waveguides with subwavelength light confinement are in principle desirable for enhancing nonlinear effects, so far it has been difficult to improve the efficiency due to the large momentum mismatch. Here we demonstrate, using remotely excited surface plasmon polaritons (SPPs), axial collimated but transversely divengent second harmonic (SH) generation in a single silver nanowire - monolayer molybdenum disulfide hybrid system...
November 15, 2017: Nano Letters
Seung-Hoon Lee, Seung Woo Lee, Taegon Oh, Sarah Hurst Petrosko, Chad A Mirkin, Jae-Won Jang
Plasmon-induced interfacial charge separation (PICS) is one of the key processes responsible for the improved conversion efficiencies of energy-harvesting devices that incorporate metal nanostructures. In this letter, we reveal a mechanism of PICS by visualizing (with nanometer-scale resolution) and characterizing plasmon-exciton coupling between p-type poly(pyrrole) (PPy) nanowires (NWs) and Ag nanoparticles (NPs) using light-irradiated Kelvin probe force microscopy (KPFM). Under blue-light irradiation, the Ag NPs are expected to donate electrons to the PPy NWs via a hot electron injection process...
November 15, 2017: Nano Letters
Zheng Wang, Dan Shao, Zhimin Chang, Mengmeng Lu, Yingshuai Wang, Juan Yue, Dian Yang, Mingqiang Li, Qiaobing Xu, Wen-Fei Dong
There is a pressing need to develop nanoplatforms that integrate multimodal therapeutics to improve treatment responses and prolong the survival of patients with unresectable hepatocellular carcinoma (HCC). Mesoporous silica-coated gold nanomaterials have emerged as a novel multifunctional platform combining tunable surface plasmon resonance and mesoporous properties that exhibit multimodality properties in cancer theranostics. However, their reduced radiation-absorption efficiency and limited surface area hinder their further radiochemotherapeutic applications...
November 17, 2017: ACS Nano
Tianhan Liu, Timothy D Keiper, Xiaolei Wang, Guang Yang, Daniel T Hallinan, Jianhua Zhao, Peng Xiong
The ability to create micro/nano patterns of organic self-assembled monolayers (SAMs) on semiconductor surfaces is crucial for fundamental studies and applications in a number of emerging fields in nanoscience. Here, we demonstrate the direct patterning of thiolate SAMs on oxide-free GaAs surface by dip-pen nanolithography (DPN) and micro-contact printing (μCP), facilitated by a process of surface etching and passivation of the GaAs. A quantitative analysis on the molecular diffusion on GaAs was conducted by examining the writing of nanoscale dot and line patterns by DPN, which agrees well with surface diffusion models...
November 15, 2017: ACS Applied Materials & Interfaces
Dmitry V Petrov, Alexey R Zaripov, Nikita A Toropov
The Letter demonstrates a possibility to enhance the Raman scattering of a gaseous medium due to an enhanced electromagnetic field caused by the excitation of propagating surface plasmon polaritons (PSPPs) on a silver holographic grating. Efficiency of collinear and noncollinear schemes of PSPP excitation on a metal-gaseous medium interface was studied. When using a collinear scheme, we registered an eightfold enhancement of the Raman scattering of atmospheric nitrogen and oxygen, where the average gain near the PSPP-active surface was ∼4×10(3)...
November 15, 2017: Optics Letters
Shurun Tan, Leung Tsang
An efficient scatterer-free full-wave solution for plane wave scattering from a half-space of two-dimensional (2D) periodic scatterers is derived using broadband Green's function. The Green's function is constructed using band solutions of the infinite periodic structure, and it satisfies boundary conditions on all the scatterers. A low wavenumber extraction technique is applied to the Green's function to accelerate the convergence of the modal expansion. This facilitates the Green's function with low wavenumber extraction (BBGFL) to be evaluated over a broadband as the modal solutions are independent of wavenumber...
November 15, 2017: Optics Letters
Wenzuo Wei, Ruijin Hong, Ming Jing, Wen Shao, Chunxian Tao, Dawei Zhang
Tunablity of localized surface plasmon resonance (LSPR) in doped semiconductor nanoparticles (NPs), which represents an important characteristic in LSPR sensor applications, still remains a challenge. Here, indium tin oxide/indium tin alloy (ITO/In-Sn) bilayer films were deposited by electron beam evaporation and the properties, such as LSPR and surface morphology, were investigated by UV-vis-NIR double beam spectrophotometer and atomic force microscopy (AFM), respectively. By simply engineering the thickness of ITO/In-Sn NPs without any microstructure fabrications, LSPR wavelength of ITO NPs can be largely tuned from 858 to 1758 nm...
November 15, 2017: Nanotechnology
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