Nanoporous Gold Leaves: preparation, optical characterization and biosensing capabilities (original) (raw)
Related papers
Optics express, 2015
We demonstrated an enhanced surface plasmon resonance (SPR) detection by incorporating a nanoporous gold film on a thin gold substrate. Nanoscale control of thickness and roughness of the nanoporous layer was successfully accomplished by oblique angle deposition. In biosensing experiments, the results obtained by biotin-streptavidin interaction showed that SPR samples with a nanoporous gold layer provided a notable sensitivity improvement compared to a conventional bare gold film, which is attributed to an excitation of local plasmon field and an increased surface reaction area. Imaging sensitivity enhancement factor was employed to estimate an overall sensor performance of the fabricated samples and an optimal SPR structure was determined. Our approach is intended to show the feasibility and extend the applicability of the nanoporous gold film-mediated SPR biosensor to diverse biomolecular binding events.
Structure and Applications of Gold in Nanoporous Form
2017
Nanoporous gold (np-Au) has many interesting and useful properties that make it a material of interest for use in many technological applications. Its biocompatible nature and ability to serve as a support for self-assembled monolayers of alkanethiols and their derivative make it a suitable support for the immobilization of carbohydrates, enzymes, proteins, and DNA. Its chemically inert, physically robust and conductive high-surface area makes it useful for the design of electrochemistry-based chemical/bio-sensors and reactors. Furthermore, it is also used as solid support for organic molecular synthesis and biomolecules separation. Its enhanced optical property has application in design of plasmonics-based sensitive biosensors. In fact, np-Au is one of the few materials that can be used as a transducer for both optical and electrochemical biosensing. Due to the presence of low-coordination surface sites, np-Au shows remarkable catalytic activity for oxidation of molecules like carb...
Nanoporous gold plasmonic structures for sensing applications
Optics Express, 2011
The fabrication, characterization and functionalization of periodically patterned nanoporous gold layers is presented. The material shows plasmonic properties in the near infrared range, with excitation and propagation of surface plasmon polaritons. Functionalization shows a marked enhancement in the optical response in comparison with evaporated gold gratings, due to a great increase of the active surface. Due to its superior response, nanoporous gold patterns appear promising for the realization of compact plasmonic platforms for sensing purposes.
Optical characterization of supported gold nanoparticles for plasmonic biosensors
CAS 2010 Proceedings (International Semiconductor Conference), 2010
Gold nanoparticles (AuNP) continue rising a strong interest for research and especially in the field of biosensors as attested by growing number of publications. One reason is that AuNP exhibit an optical response dominated by the localised surface plasmon resonance (LSPR) that is highly sensitive to the molecular environment. This paper describes the preparation of monodisperse supported AuNP and their characterization by optical UV-visible spectroscopy. It is shown how the surface density of AuNP can be extracted from the spectra, using a complementary check against AFM images. An example of a plasmonic biosensor capable of the specific recognition of avidin is presented.
Patterned nanoporous-gold thin layers: Structure control and tailoring of plasmonic properties
A robust and reproducible preparation of self-standing nanoporous gold leaves (NPGL) is presented, with optical characterization and plasmonic behaviour analysis. Nanoporous gold (NPG) layers are tipically prepared as thin films on a bulk substrate. Here we present an alternative approach consisting in the preparation of NPGL in the form of a self-standing film. This solution leads to a perfectly symmetric configuration where the metal is immersed in a homogeneous medium and in addition can support the propagation of symmetric and antisymmetric plasmonic modes. With respect to bulk gold, NPG shows metallic behaviour at higher wavelengths, suggesting possible plasmonic applications in the near / medium infrared range. In this work the plasmonic properties in the wide wavelength range from the ultraviolet up to the mid-infrared range have been investigated.
Application of Gold Nanoparticle to Plasmonic Biosensors
International journal of molecular sciences, 2018
Gold nanoparticles (GNPs) have been widely utilized to develop various biosensors for molecular diagnosis, as they can be easily functionalized and exhibit unique optical properties explained by plasmonic effects. These unique optical properties of GNPs allow the expression of an intense color under light that can be tuned by altering their size, shape, composition, and coupling with other plasmonic nanoparticles. Additionally, they can also enhance other optical signals, such as fluorescence and Raman scattering, making them suitable for biosensor development. In this review, we provide a detailed discussion of the currently developed biosensors based on the aforementioned unique optical features of GNPs. Mainly, we focus on four different plasmonic biosensing methods, including localized surface plasmon resonance (LSPR), surface-enhanced Raman spectroscopy (SERS), fluorescence enhancement, and quenching caused by plasmon and colorimetry changes based on the coupling of GNPs. We be...
Nanomaterials
Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning pore and ligament sizes. The np-Au electrodes that are prepared using electrochemical techniques are robust and are easier to handle for their use in electrochemical biosensing. Here, we review different electrochemical strategies for the preparation, post-modification, and characterization of np-Au along with the synergistic use of both electrochemistry and np-Au for applications in biosensing.
Designing Efficient Plasmonic Biosensors Based on Gold Metallic Nanostructures
Journal of nanotechnology and smart materials , 2023
The increasing need for plasmonic bio-sensing devices that require analytical platforms which are efficient, instant, extreme sensitivity, and real-time response, have yielded a significant change in the design them in recent years. The development of sensors based on plasmonic nanostructures has exhibited the best quality approach to integrate them in the lab-on-chip platforms with miniaturization and multiplexing. The main goal of this study was to design a highly sensitive nano-sensor based on metallic nanostructures and to investigate the effect of size and shape on the optical properties of metallic nanoparticles in very large spectral range (λ =500-1200 nm) using simulation for nanoparticles of sizes (D = 100-200 nm). In particular, the optical properties of gold nanoparticles were investigated using the Finite-Difference Time-Domain (FDTD) method. The wavelength corresponding to the maximum scattering redshifts (shift to longer wavelengths) were observed as the nanoparticle size increased. The influences of Au NP size and shape were analyzed in detail. The gold nanoparticle diameter between 100 nm to 200 nm is used in determine the shifting of the surface plasmon resonance. The results in this work indicated that the position of the plasmon resonance wavelength for gold nanoparticle was redshift when the size of gold nanoparticle was increased. Data was collected after designing the simulation of nanoplasmonic structures using Finite-Difference-in Time-Domain (FDTD) software. The major finding showed that adjusting of Au nanoparticles sizes/diameters and varying the sensing environment enhanced the resonance wavelength shift; this increased the sensitivity of Au nanoparticles. This study offers a new insight regarding biosensors based on plasmonic nanoparticles and it will provide opportunities for developing Plasmon-enabled applications in biomedicine.