Arrangement Of Silver Nanostructures on Permeable Silicon and Examination of Their Optical Properties

Considers of nanostructures created beneath different modes of submersion testimony of silver on permeable silicon (PS) for their utility as dynamic substrates in monster Raman spectroscopy (SRS) are displayed. PS was shaped by anodizing monocrystalline silicon in an aqueous-alcoholic arrangement of hydrofluoric corrosive. The reflection spectra of the gotten silver nanostructures on PC have been examined. It is uncovered that to form ideal conditions for SERS spectroscopy utilizing silver nanostructures on PC, it is vital to utilize an energizing laser with a wavelength of 400–450 nm.

Direct Writing on Paper Substrate to Prepare Silver Electrode Structures for Flexible Sensors

With the rapid development of the electronics industry, electronic products based on silicon and glass substrates electronic products will gradually be unable to meet the rising demand. Flexibility, environmental protection, and low costs are important for the development of electronic products. In this study, an efficient and low-cost method for preparing silver electrode structures by direct writing on paper has been demonstrated. Based on this method, a flexible paper-based sensor was prepared. The liquid printing ink used mainly comprises a precursor liquid without pre-prepared nanomaterials. The precursor liquid is transparent with good fluidity. Simple direct writing technology was used to write on the paper substrate using the precursor ink. When the direct-writing paper substrate was subsequently heated, silver nanostructures precipitated from the precursor liquid ink onto the paper substrate. The effect of different temperatures on the formation of the silver nanostructures and the influence of different direct writing processes on the structures were studied. Finally, a paper-based flexible sensor was prepared for finger-bending signal detection. The method is simple to operate and low in cost and can be used for the preparation of environment-friendly paper-based devices.

Silver Nanostructures: Limited Sensitivity of Detection, Toxicity and Anti-Inflammation Effects

Nanosilver with sizes 1–100 nm at least in one dimension is widely used due to physicochemical, anti-inflammatory, anti-angiogenesis, antiplatelet, antifungal, anticancer, antibacterial, and antiviral properties. Three modes of the nanosilver action were suggested: “Trojan horse”, inductive, and quantum mechanical. The Ag+ cations have an affinity to thiol, amino, phosphate, and carboxyl groups. Multiple mechanisms of action towards proteins, DNA, and membranes reduce a risk of pathogen resistance but inevitably cause toxicity for cells and organisms. Silver nanoparticles (AgNP) are known to generate two reactive oxygen species (ROS)-superoxide (•O2−) and hydroxyl (•OH) radicals, which inhibit the cellular antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and cause mechanical damage of membranes. Ag+ release and replacement by electrolyte ions with potential formation of insoluble AgCl result in NP instability and interactions of heavy metals with nucleic acids and proteins. Protein shells protect AgNP core from oxidation, dissolution, and aggregation, and provide specific interactions with ligands. These nanoconjugates can be used for immunoassays and diagnostics, but the sensitivity is limited at 10 pg and specificity is restricted by binding with protective proteins (immunoglobulins, fibrinogen, albumin, and others). Thus, broad implementation of Ag nanostructures revealed limitations such as instability; binding with major blood proteins; damage of proteins, nucleic acids, and membranes; and immunosuppression of the majority of cytokines.

Photodegradation of Biohazardous Dye Brilliant Blue R Using Organometallic Silver Nanoparticles Synthesized through a Green Chemistry Method

Nowadays, nanostructures having tremendous chemical and physical properties are gaining attention in the biomedical industry. However, when they are prepared through classical methods (physical and chemical), they are often non-biocompatible and toxic. Considering the mentioned factors, in this research, organometallic silver nanostructures (OMAgNs) have been prepared by the green chemistry method using the acetone, methanol, and methanol-hexane-based extracts of the medicinally important plant Cichorium intybus. Secondary metabolites from C. intybus can be used as an alternative to synthetic reagents at an industrial scale to manufacture biosafe and economical nanostructures with enhanced physicochemical parameters. Prepared nanostructures were characterized using SEM, XRD, FTIR, TGA, UV, and zeta potential measurement. SEM analysis revealed different shapes of OMAgNs, prepared with various extracts. XRD analysis showed the crystallinity of the nanostructures. FTIR spectroscopy helped to identify groups of compounds present in the extracts and used for the OMAgNs synthesis. Out of the three tested OMAgNs, those prepared with methanol extract were selected due to the highest obtained yield and stability (highest negative zeta potential) and were tested as a cost-efficient and active agent to photodegrade organic pollutant, Brilliant Blue R, using energy from sunlight. A decrease in UV-VIS absorbance confirmed the rapid degradation of the dye.

Fluorescence Enhancement via Dual Coupling of Dye Molecules with Silver Nanostructures

We demonstrate the enhancement of fluorescence emitted from dye molecules coupled with two surface plasmons, i.e., silver nanoparticles (AgNPs)-induced localized surface plasmons (LSP) and thin silver (Ag) film supported surface plasmons. Excitation light is illuminated to a SiO2 layer that contains both rhodamine 110 molecules and AgNPs. AgNPs enhances excitation rates of dye molecules in their close proximity due to LSP-induced enhancement of local electromagnetic fields at dye excitation wavelengths. Moreover, the SiO2 layer on one surface of which a 50 nm-thick Ag film is coated for metal cladding (air on the other surface), acts as a waveguide core at the dye emission wavelengths. The Ag film induces the surface plasmons which couple with the waveguide modes, resulting in a waveguide-modulated version of surface plasmon coupled emission (SPCE) for different SiO2 thicknesses in a reverse Kretschmann configuration. We find that varying the SiO2 thickness modulates the fluorescent signal of SPCE, its modulation behavior being in agreement with the theoretical simulation of thickness dependent properties of the coupled plasmon waveguide resonance. This enables optimization engineering of the waveguide structure for enhancement of fluorescent signals. The combination of LSP enhanced dye excitation and the waveguide-modulated version of SPCE may offer chances of enhancing fluorescent signals for a highly sensitive fluorescent assay of biomedical and chemical substances.