Surface-enhanced optical microscopy

In the following, it will be demonstrated that confocal surface-enhanced Raman microscopy is a powerful tool for exploring optical and spectroscopic properties of molecules adsorbed on silver and gold nanoparticles. It is shown that confocal Raman microscopy coupled with high-resolution electron microscopy has the potential to deliver detailed information about the structure of points of high Raman intensity the so-called hot spots. 

Figure 2.2 Optical probe of surface-enhanced microscopy proposed byj. Wessel. A metallic nanoparticle attached to a glass substrate confines and enhances the light field.

Label-free optical techniqnes for detecting bound proteins on microarrays have been recently reviewed. The advantage of these methods over labeling methods is that the native form of the analyte is preserved. These methods include SPR, surface-enhanced laser desorption/ionization mass spectrometry (SELDI-MS), atomic force microscopy " and fiber-optic methods. 

The effect, on dispersion and de-agglomeration in water, of electrostatic repulsion force arising from the surface potential and the double layer 1/x around particles has been investigate. Several suspensions of polystyrene latex in an agglomerated state were prepared where j/ and 1 x were controlled by the pH and electrolyte concentration respectively. These were accelerated in a convergent nozzle to give an external force and the resulting dispersions were examined by optical microscopy. It was found that the dispersion was enhanced with an increase in y/and 1/x. 

Fortunately, the success of surface science, optical and x-ray techniques in the last few decades has provided access for electrochemists to structural information of electrode/electrolyte interfaces. The optical and X-ray spectroscopic techniques have mainly been used in situ, i.e., in the presence of the bulk electrolyte. These techniques include EXAFS (extended x-ray absorption fine structure), SXS (surface x-ray scattering), XSff (x-ray standing wave technique, SERS (surface enhanced Raman scattering), NOM (nonlinear optical methods) IRS (infrared spectroscopy), MS (Mossbauer spectroscopy), RLS (radioactive labelling spectroscopy), STM (scanning tunneling microscopy), and... 

The A. coerulea material was poorly crystalline, showing a broad peak at 20° 20, but the spectrum for the alkali-treated material showed a broad peak at 10.72° and two peaks at 18.72° and 19.98° 20, with close similarity to the spectrum of authentic chitosan. Optical microscopy showed that the alkali-treated products, stained with Saphranine or with other stains, preserved the morphology of the fungus, with flattened and empty structures [30] (Fig. 1). This work introduced the concept that an extended surface area of the carbohydrate polymer leads to enhanced performance, as amply confirmed by most recent works dealing with chitin and chitosan nanofibrils. In fact, the partially re-acetylated chitosan (degree of acetylation 0.23) is promptly depolymerized by lysozyme, papain, and lipase thanks to the ideal degree of acetylation for maximum enzymatic activity. Remarkably, the re-acetylated... 

NEAR-FIELD SCANNING OPTICAL MICROSCOPY STUDIES OF THE FLUORESCENCE ENHANCEMENT ON THE SURFACE OF METAL NANOPARTICLES... 

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