scholarly journals BIOFUNCTIONALIZATION OF GOLD NANOSHELLS

2018 ◽  
Vol 56 (5) ◽  
Author(s):  
Nghiem Thi Ha Lien

Gold nanoshells were grown on monodispersed and aminopropyltriethoxysilane (APTES) functionalized silica nanoparticles cores with varying sizes ranging from 40-180 nm, which were prepared by Stober route. Gold shells were deposited onto the surface of silica NPs by using tetrakis(hydroxymethyl) phosphonium chloride  and electroless gold plating method. The coverage of the gold nanoshells on the surfaces of the silica NPs was evaluated using surface plasmon resonance spectra and scanning electron microscope.

2022 ◽  
Vol 7 (1) ◽  
pp. 76-85
Author(s):  
Athiah Masykuroh ◽  
Heny Puspasari

Biosintesis Nano partikel perak (NPP) pada penelitian ini dilakukan dengan bantuan ekstrak air tanaman keladi sarawak Alocasia macrorrhizos sebagai bioreduktor dengan variasi konsentrasi larutan AgNO3 sebesar 0,05 M ; 0,10 M dan 0,15 M. Studi keberhasilan pembentukan NPP didasarkan pada pengamatan perubahan warna dan terbentuknya Surface Plasmon Resonance (SPR) dengan bantuan instrumen Spektofotometer UV-Visibel dan Scanning Electron Microscope (SEM). Uji Aktivitas antibakteri dilakukan dengan metode difusi kertas cakram. Hasil analisis menunjukkan bahwa NPP terbentuk maksimum pada panjang gelombang maksimum 450,00 nm yaitu pada variasi konsentrasi larutan AgNO3 0,15 M. Uji morfologi menggunakan SEM menunjukkan partikelnya berbentuk batang (nanorods) dengan ukuran diameter rata-rata masing-masing variasi 826,44 nm (0,05 M), 283,44 nm (0,10 M) dan 266,33 nm (0,15 M). NPP hasil biosintesis menunjukkan aktivitas antibakteri terhadap kedua jenis bakteri Staphylococcus aureus dan Escherichia coli pada pengenceran konsentrasi masing-masing variasi NPP sebesar 50%. Kata kunci :nanopartikel perak, keladi sarawak, staphylococcus aureus, escherichia coli


2021 ◽  
Vol 7 (1) ◽  
pp. 12-20
Author(s):  
Athiah Masykuroh ◽  
Nadia Nia Nurulita

Nowadays silver nanoparticles (AgNPs) synthesized so often by plant extracts as a reductor. The synthesis of AgNPs was carried out by Citrus microcarpa Bunge fruit peel extract a reductor in various extract concentrations (10, 15, and 20%), concentration of AgNO3 solution of 0.15M and temperature of 700C. The presence of AgNPs was determined by color test and the formation of Surface Plasmon Resonance (SPR) using UV-Vis Spectrophotometer while to determine the morphology and size of the nanoparticles using Scanning Electron  Microscope (SEM). The results of the analysis showed that AgNPs was formed at colloidal phase with dark brown color with wavelengths of 457.30 nm, 478.90 nm, and 422.80 nm for variation concentration of 10, 15 and 20% with slightly spherical, slightly elongated and jagged morphology with average size of 253.8 nm (10%), 254.2 nm (15%) and 253.9 nm (20%).


Author(s):  
R. E. Ferrell ◽  
G. G. Paulson

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.


Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.


Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.


Author(s):  
S. Takashima ◽  
H. Hashimoto ◽  
S. Kimoto

The resolution of a conventional transmission electron microscope (TEM) deteriorates as the specimen thickness increases, because chromatic aberration of the objective lens is caused by the energy loss of electrons). In the case of a scanning electron microscope (SEM), chromatic aberration does not exist as the restrictive factor for the resolution of the transmitted electron image, for the SEM has no imageforming lens. It is not sure, however, that the equal resolution to the probe diameter can be obtained in the case of a thick specimen. To study the relation between the specimen thickness and the resolution of the trans-mitted electron image obtained by the SEM, the following experiment was carried out.


Author(s):  
R. F. Schneidmiller ◽  
W. F. Thrower ◽  
C. Ang

Solid state materials in the form of thin films have found increasing structural and electronic applications. Among the multitude of thin film deposition techniques, the radio frequency induced plasma sputtering has gained considerable utilization in recent years through advances in equipment design and process improvement, as well as the discovery of the versatility of the process to control film properties. In our laboratory we have used the scanning electron microscope extensively in the direct and indirect characterization of sputtered films for correlation with their physical and electrical properties.Scanning electron microscopy is a powerful tool for the examination of surfaces of solids and for the failure analysis of structural components and microelectronic devices.


Author(s):  
S. Saito ◽  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda

Field emission scanning electron microscope (FESEM) features extremely high resolution images, and offers many valuable information. But, for a specimen which gives low contrast images, lateral stripes appear in images. These stripes are resulted from signal fluctuations caused by probe current noises. In order to obtain good images without stripes, the fluctuations should be less than 1%, especially for low contrast images. For this purpose, the authors realized a noise compensator, and applied this to the FESEM.Fig. 1 shows an outline of FESEM equipped with a noise compensator. Two apertures are provided gust under the field emission gun.


Author(s):  
Emil Bernstein

An interesting method for examining structures in g. pig skin has been developed. By modifying an existing technique for splitting skin into its two main components—epidermis and dermis—we can in effect create new surfaces which can be examined with the scanning electron microscope (SEM). Although this method is not offered as a complete substitute for sectioning, it provides the investigator with a means for examining certain structures such as hair follicles and glands intact. The great depth of field of the SEM complements the technique so that a very “realistic” picture of the organ is obtained.


Author(s):  
C.V.L. Powell

The overall fine structure of the eye in Placopecten is similar to that of other scallops. The optic tentacle consists of an outer columnar epithelium which is modified into a pigmented iris and a cornea (Fig. 1). This capsule encloses the cellular lens, retina, reflecting argentea and the pigmented tapetum. The retina is divided into two parts (Fig. 2). The distal retina functions in the detection of movement and the proximal retina monitors environmental light intensity. The purpose of the present study is to describe the ultrastructure of the retina as a preliminary observation on eye development. This is also the first known presentation of scanning electron microscope studies of the eye of the scallop.


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