Hybrid Polystyrene-Plasmonic Systems as High Binding Density Biosensing Platforms.

Sensitive, accurate, and early detection of biomarkers is essential for prompt response to medical decisions for saving lives. Some infectious diseases are deadly even in small quantities and require early detection for patients and public health. The scarcity of these biomarkers necessitates signal amplification before diagnosis.

Laser-scribed conductive, photoactive transition metal oxide on soft elastomers for Janus on-skin electronics and soft actuators.

Laser-assisted fabrication of conductive materials on flexible substrates has attracted intense interests because of its simplicity, easy customization, and broad applications. However, it remains challenging to achieve laser scribing of conductive materials on tissue-like soft elastomers, which can serve as the basis to construct bioelectronics and soft actuators. Here, we report laser scribing of metallic conductive, photoactive transition metal oxide (molybdenum dioxide) on soft elastomers, coated with molybdenum chloride precursors, under ambient conditions.

Enhanced Third Harmonic Generation in Lead Bromide Perovskites with Ruddlesden-Popper Planar Faults.

Lead halide perovskites provide a test bed for exploring nonlinear optical properties. Although the underlying centrosymmetric crystal structure of 3D lead halide perovskites precludes the phenomenon of second harmonic generation, the third and higher-order harmonic generation are allowed. In this work, we probe the third harmonic generation (THG) from CsPbBr nanocrystals (NCs) and compare it to the THG from CsPbBr NCs with Ruddlesden-Popper planar faults (RP-CsPbBr), formed via postsynthetic fusion-growth.

Spontaneous emission rate enhancement with aperiodic Thue-Morse multilayer.

The emergence of multilayer metamaterials in the research field of enhancing spontaneous emission rates has recently received extensive attention. Previous research efforts mostly focus on periodic metal-dielectric multilayers in hyperbolic dispersion region; however, the influence of lattice order in subwavelength multilayers on spontaneous emission is rarely studied. Here, we observe the stronger Purcell enhancement of quantum dots coupled to the aperiodic metal-dielectric multilayer with Thue-Morse lattice order from elliptical to hyperbolic dispersion regions, compared to the periodic multilayer with the same metal filling ratio.

Ultrasensitive detection of lipoarabinomannan with plasmonic grating biosensors in clinical samples of HIV negative patients with tuberculosis.

Background: Timely diagnosis of tuberculosis disease is critical for positive patient outcomes, yet potentially millions go undiagnosed or unreported each year. Sputum is widely used as the testing input, but limited by its complexity, heterogeneity, and sourcing problems. Finding methods to interrogate noninvasive, non-sputum clinical specimens is indispensable to improving access to tuberculosis diagnosis and care.

Nanoscale surface reactions by laser irradiation of Al nanoparticles on MoO flakes.

Surface reactions between heated aluminum nanoparticles (Al NPs) and thin α-MoO sheets are investigated. Localized photothermal heating on Al NP clusters is provided by a Raman spectrometer laser, while enhanced heating rates and imaging resolution are enabled by the use of a plasmonic grating substrate. Prominent linear reaction zones extending from Al NPs in the 〈001〉 crystal direction are observed on the surface of the host MoO sheets after heating.

Ultra-broadband infrared absorption by tapered hyperbolic multilayer waveguides.

Ultra-broadband strong absorption over 92% covering the infrared wavelength range of 1~6μm is demonstrated by using the tapered hyperbolic Au-SiO multilayer waveguides on glass substrates. Such broadband absorption is formed by the stop-light modes at various wavelengths located at different waveguide widths. A planar hyperbolic waveguide model is built to determine the stop-light modes by considering both forward and backward guided modes.

Single-Molecule Surface Plasmon-Coupled Emission with Plasmonic Gratings.

The ability to image single molecules (SM) has been the dream of scientists for centuries, and because of the substantial recent advances in microscopy, individual fluorescent molecules can now be observed on a regular basis. However, the development of such imaging systems was not without dilemmas, such as the detection and separation of individual fluorescence emissions. One method to solve this problem utilized surface plasmon resonance (SPR) to enhance the emission intensity of SMs.

Plasmonic nano-protrusions: hierarchical nanostructures for single-molecule Raman spectroscopy.

Classical methods for enhancing the electromagnetic field from substrates for spectroscopic applications, such as surface-enhanced Raman spectroscopy (SERS), have involved the generation of hotspots through directed self-assembly of nanoparticles or by patterning nanoscale features using expensive nanolithography techniques. A novel large-area, cost-effective soft lithographic technique involving glancing angle deposition (GLAD) of silver on polymer gratings is reported here. This method produces hierarchical nanostructures with high enhancement factors capable of analyzing single-molecule SERS.

Room temperature Coulomb blockade effects in Au nanocluster/pentacene single electron transistors.

Single-electron transistors incorporating single ∼1 nm gold nanocluster (AuNCs) and pentacene as a complex charge transport system have been used to study the quantum Coulomb blockade and its single electron tunnelling behaviour at room temperature (RT) (300 K). Monodisperse ultra-small (0.86 ± 0.

Experimental characterization of optical nonlocality in metal-dielectric multilayer metamaterials.

The optical nonlocality in metal-dielectric multilayer metamaterials is characterized experimentally as a function of the angle of incidence with respect to the TE-polarized incident light. The physical mechanism of the difference between the nonlocal effective permittivity and the effective-medium-theory-based effective permittivity depending on the incident angle is theoretically revealed through the analysis of the band structure, the dispersion relation, and the iso-frequency contours according to the transfer-matrix method. Such effective permittivity difference is also retrieved in the metal-dielectric multilayers based on the measured transmission and reflection spectra.

Sub-2 nm size and density tunable platinum nanoparticles using room temperature tilted-target sputtering.

This paper describes a tilted-target RF magnetron sputter deposition system to grow nanoparticles in a controlled way. With detailed characterization of ultra-high density (up to 1.1 × 10¹³ cm⁻²) and ultra-small size Pt nanoparticles (0.

Transparent Electrode Materials for Simultaneous Amperometric Detection of Exocytosis and Fluorescence Microscopy.

We have developed and tested transparent microelectrode arrays capable of simultaneous amperometric measurement of oxidizable molecules and fluorescence imaging through the electrodes. Surface patterned microelectrodes were fabricated from three different conducting materials: Indium-tin-oxide (ITO), nitrogen-doped diamond-like carbon (DLC) deposited on top of ITO, or very thin (12-17 nm) gold films on glass substrates. Chromaffin cells loaded with lysotracker green or acridine orange dye were placed atop the electrodes and vesicle fluorescence imaged with total internal reflection fluorescence (TIRF) microscopy while catecholamine release from single vesicles was measured as amperometric spikes with the surface patterned electrodes.

Microwell device for targeting single cells to electrochemical microelectrodes for high-throughput amperometric detection of quantal exocytosis.

Electrochemical microelectrodes are commonly used to detect spikes of amperometric current that correspond to exocytosis of oxidizable transmitter from individual vesicles, i.e., quantal exocytosis.