Local Surface Plasmonic Resonance, Surface-Enhanced Raman Scattering, Photoluminescence, and Photocatalytic Activity of Hydrothermal Titanate Nanotubes Coated with Ag Nanoparticles

In this work, we successfully fabricated homogeneous hydrothermal titanate nanotubes (TNTs) coated with Ag nanoparticles (NPs) and elucidated the role of Ag NPs on local surface plasmonic resonance, surface-enhanced Raman scattering, and the enhanced photocatalytic activity of TNT/Ag nanocomposite. The results showed that the photodegradation process reached equilibrium in just ~5 min for the TNT/Ag nanocomposite, which was much shorter than that of the TNT sample (~90 min). TEM micrographs showed that Ag NPs were well dispersed on the walls of the nanotubes. XRD patterns and Raman spectra indicated that the TNTs were in the monoclinic structure of H2Ti3O7. Furthermore, Raman active modes of the TNTs were significantly enhanced in the TNT/Ag sample, which was attributed to surface-enhanced Raman spectroscopy. The enhanced photocatalytic activity of the TNT/Ag sample was explained by UV-vis diffuse reflectance spectroscopy and photoluminescence emission spectroscopy, which showed local surface plasmonic resonance-induced visible light absorption enhancement and effective charge separation, respectively.

Strong Modulation of Short Wind Waves and Ka-Band Radar Return Due to Internal Waves in the Presence of Surface Films. Theory and Experiment

Strong variability of Ka-band radar backscattering from short wind waves on the surface of water covered with surfactant films in the presence of internal waves (IW) was studied in wave tank experiments. It has been demonstrated that modulation of Ka-band radar return due to IW strongly depends on the relationship between the phase velocity of IW and the velocity of drifting surfactant films. An effect of the strong increase in surfactant concentration was revealed in convergent zones, associated with IW orbital velocities in the presence of a “resonance” surface steady current, the velocity of which was close to the IW phase velocity. A phenomenological model of suppression and modulations in the spectrum of small-scale wind waves due to films and IW was elaborated. It has been shown that backscatter modulation could not be explained by the modulation of free (linear) millimeter-scale Bragg waves, but was associated with the modulation of bound (parasitic) capillary ripples generated by longer, cm–dm-scale waves—a “cascade” modulation mechanism. Theoretical analysis based on the developed model was found to be consistent with experiments. Field observations which qualitatively illustrated the effect of strong modulation of Ka-band radar backscatter due to IW in the presence of resonance drift of surfactant films are presented.

Graphene-Based Biosensors for Detection of Biomarkers

The development of biosensors with high sensitivity and low-detection limits provides a new direction for medical and personal care. Graphene and graphene derivatives have been used to prepare various types of biosensors due to their excellent sensing performance (e.g., high specific surface area, extraordinary electronic properties, electron transport capabilities and ultrahigh flexibility). This perspective review focuses on graphene-based biosensors for quantitative detection of cancer-related biomarkers such as DNA, miRNA, small molecules and proteins by integrating with different signal outputting approaches including fluorescent, electrochemistry, surface plasmon resonance, surface enhanced Raman scattering, etc. The article also discussed their challenges and potential solutions along with future prospects.

Role of chemical interface damping for tuning chemical enhancement in resonance surface-enhanced Raman scattering of plasmonic gold nanorods

Chemical interface damping in plasmonic gold nanoparticles is closely connected with chemical enhancement in resonance SERS.

Graphene-Based Biosensors for Detection of Biomarkers

The development of biosensors with high sensitivity and low-detection limits provides a new direction for medical and personal care. Graphene and graphene derivatives have been used to prepare various types of biosensors due to their excellent sensing performance (e.g. high specific surface area, extraordinary electronic properties, electron transport capabilities and ultrahigh flexibility). This perspective review focuses on graphene-based biosensors for quantitative detection of cancer related biomarkers such as DNA, miRNA, small molecules and proteins by integrating with different signal outputting approaches including fluorescent, electrochemistry, surface plasmon resonance, surface enhanced Raman scattering etc. The article also discussed their challenges and potential solutions along with future prospects.