scholarly journals Biomedical potential of Anabaena variabilis NCCU-441 based Selenium nanoparticles and their comparison with commercial nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bushra Afzal ◽  
Durdana Yasin ◽  
Haleema Naaz ◽  
Neha Sami ◽  
Almaz Zaki ◽  
...  
Keyword(s):  
Color Change ◽  
Biomedical Application ◽  
High Surface ◽  
High Surface Area ◽  
Reduction Process ◽  
Cell Extract ◽  
Anabaena Variabilis ◽  
Selenium Nanoparticles ◽  
Biochemical Compounds ◽  
Antibacterial And Antifungal

AbstractSelenium nanoparticles (SeNPs) are gaining importance in the field of medicines due to their high surface area and unique properties than their other forms of selenium. In this study, biogenic selenium nanoparticles (B-SeNPs) were synthesized using cyanobacteria and their bioactivities (antioxidant, antimicrobial, anticancer and biocompatibility) were determined for comparison with commercially available chemically synthesized selenium nanoparticles (C-SeNPs). Color change of reaction mixture from sky blue to orange-red indicated the synthesis of biogenic SeNPs (B-SeNPs). UV–Vis spectra of the reaction mixture exhibited peak at 266 nm. During optimization, 30 °C of temperature, 24 h of time and 1:2 concentration ratio of sodium selenite and cell extract represented the best condition for SeNPs synthesis. Various functional groups and biochemical compounds present in the aqueous extract of Anabaena variabilis NCCU-441, which may have possibly influenced the reduction process of SeNPs were identified by FT-IR spectrum and GC–MS. The synthesized cyanobacterial SeNPs were orange red in color, spherical in shape, 10.8 nm in size and amorphous in nature. The B-SeNPs showed better anti-oxidant (DPPH, FRAP, SOR and ABTS assays), anti-microbial (antibacterial and antifungal) and anti-cancer activitities along with its biocompatibility in comparison to C-SeNPs suggesting higher probability of their biomedical application.

High surface area mesoporous SiC synthesized via nanocasting and carbothermal reduction process

2005 ◽  
Vol 40 (18) ◽  
pp. 5091-5093 ◽  
Author(s):  
AN-HUI LU ◽  
WOLFGANG SCHMIDT ◽  
WOLFGANG KIEFER ◽  
FERDI SCHÜTH
Keyword(s):  
Surface Area ◽  
Carbothermal Reduction ◽  
High Surface ◽  
High Surface Area ◽  
Reduction Process

Chitosan Aerogels Exhibiting High Surface Area for Biomedical Application: Preparation, Characterization, and Antibacterial Study

2011 ◽  
Vol 60 (12) ◽  
pp. 988-999 ◽  
Author(s):  
Kumari Rinki ◽  
Pradip K. Dutta ◽  
Andrew J. Hunt ◽  
Duncan J. Macquarrie ◽  
James H. Clark
Keyword(s):  
Surface Area ◽  
Biomedical Application ◽  
High Surface ◽  
High Surface Area ◽  
Antibacterial Study

Novel synthesis of high surface area SiC by carbothermal reduction process

2014 ◽  
Vol 19 (2) ◽  
pp. 155-159 ◽  
Author(s):  
J. Y. Hao ◽  
Y. Y. Wang ◽  
C. W. Gong ◽  
Y. M. Tian ◽  
L. P. Liang
Keyword(s):  
Surface Area ◽  
Carbothermal Reduction ◽  
High Surface ◽  
High Surface Area ◽  
Reduction Process ◽  
Novel Synthesis

scholarly journals Silica Nanoparticles for Biomedical Application: Challenges and Opportunities

2020 ◽  
Author(s):  
E.A. Mun ◽  
B.A. Zhaisanbayeva
Keyword(s):  
Silica Nanoparticles ◽  
Surface Area ◽  
Biomedical Application ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Drug Carriers ◽  
High Reactivity ◽  
Diagnostic Tools ◽  
Gene Delivery Vectors

Over the past few decades, nanoparticles have been attracting significant attention of researches in chemical, biomedical, pharmaceutical sciences, due to their unique physicochemical properties. This includes ultra small size, large surface area, good biocompatibility and high reactivity. In particular, nanoparticles are promising for pharmaceutical and biomedical fields, as they can be applied as drug carriers and diagnostic tools. Among nanomaterials for biomedical application, silica nanoparticles exhibit great potential due to their straightforward synthesis and separation, low cost, safety, biocompatibility and possibility to further functionalization. Silica nanoparticles have been attractive for pharmaceutical science due to their unique properties, such as tunable size, high surface area and large pore volume, and potential in biomedical application as drug and gene delivery vectors and bioimaging agents. However, some of their properties remain poorly investigated. This short communication discusses the main routes for synthesis of silica nanoparticles, their properties and opportunities for their application in pharmaceutical and biomedical industries, as well as a few challenges in the development of silica-based systems that need to be overcome.

Development of Mesoporous Magnetic Hydroxyapatite Nanocrystals

2018 ◽  
Vol 916 ◽  
pp. 161-165
Author(s):  
Hsi Chin Wu ◽  
J.Y. Lin ◽  
Tzu Wei Wang
Keyword(s):  
Biomedical Application ◽  
Lattice Structure ◽  
Drug Loading ◽  
High Surface ◽  
High Surface Area ◽  
3T3 Cells ◽  
One Step ◽  
Hydroxyapatite Nanocrystals ◽  
20 Nm

Mesoporous magnetic hydroxyapatite nanocrystals (MPmHAp NCs) were successfully prepared through one-step co-precipitate process. From the results, the MPmHAp NCs kept HAp lattice structure and had short rod-like morphology with superparamagnetic property. The size of MPmHAp was 60-80 nm in length and 10-20 nm in width. It also had excellent cell viability when coculture with 3T3 cells in vitro. In addition, MPmHAp NCs not only possessed mesoporous architecture with high surface area for effective drug loading capacity and drug release. The above results indicate that the biocompatible MPmHAp NCs showed great potential as multifunctional therapeutic nanoagent for biomedical application.

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

Electron holography of catalysts

1995 ◽  
Vol 53 ◽  
pp. 416-417
Author(s):  
A. K. Datye ◽  
D. S. Kalakkad ◽  
L. F. Allard ◽  
E. Völkl
Keyword(s):  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Atomic Scale ◽  
Nano Particles ◽  
Phase Image ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Phase Information ◽  
Particle Structure

The active phase in heterogeneous catalysts consists of nanometer-sized metal or oxide particles dispersed within the tortuous pore structure of a high surface area matrix. Such catalysts are extensively used for controlling emissions from automobile exhausts or in industrial processes such as the refining of crude oil to produce gasoline. The morphology of these nano-particles is of great interest to catalytic chemists since it affects the activity and selectivity for a class of reactions known as structure-sensitive reactions. In this paper, we describe some of the challenges in the study of heterogeneous catalysts, and provide examples of how electron holography can help in extracting details of particle structure and morphology on an atomic scale.Conventional high-resolution TEM imaging methods permit the image intensity to be recorded, but the phase information in the complex image wave is lost. However, it is the phase information which is sensitive at the atomic scale to changes in specimen thickness and composition, and thus analysis of the phase image can yield important information on morphological details at the nanometer level.

Structure and composition of metal particles in Pt-Sn/Al2O3 bimetallic catalysts

1990 ◽  
Vol 48 (4) ◽  
pp. 278-279
Author(s):  
A. Sachdev ◽  
J. Schwank
Keyword(s):  
Bimetallic Catalysts ◽  
Bimetallic Catalyst ◽  
Size Structure ◽  
High Surface ◽  
High Surface Area ◽  
Metal Particles ◽  
Alloy Formation ◽  
Particle Size Range ◽  
Oxide Supports ◽  
Petroleum Fractions

Platinum - tin bimetallic catalysts have been primarily utilized in the chemical industry in the catalytic reforming of petroleum fractions. In this process the naphtha feedstock is converted to hydrocarbons with higher octane numbers and high anti-knock qualities. Most of these catalysts contain small metal particles or crystallites supported on high surface area insulating oxide supports. The determination of the structure and composition of these particles is crucial to the understanding of the catalytic behavior. In a bimetallic catalyst it is important to know how the two metals are distributed within the particle size range and in what way the addition of a second metal affects the size, structure and composition of the metal particles. An added complication in the Pt-Sn system is the possibility of alloy formation between the two elements for all atomic ratios.

Intercalation of First Row Transition Metals inside Covalent-Organic Frameworks (COF): a Strategy to Fine Tune the Electronic Properties of Porous Crystalline Materials

2018 ◽  
Author(s):  
Srimanta Pakhira ◽  
Jose Mendoza-Cortes
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Electronic Properties ◽  
High Surface ◽  
Electronic Devices ◽  
High Surface Area ◽  
Main Role ◽  
Covalent Organic Frameworks ◽  
Porous Network ◽  
Crystalline Materials

<div>Covalent organic frameworks (COFs) have emerged as an important class of nano-porous crystalline materials with many potential applications. They are intriguing platforms for the design of porous skeletons with special functionality at the molecular level. However, despite their extraordinary properties, it is difficult to control their electronic properties, thus hindering the potential implementation in electronic devices. A new form of nanoporous material, COFs intercalated with first row transition metal is proposed to address this fundamental drawback - the lack of electronic tunability. Using first-principles calculations, we have designed 31 new COF materials <i>in-silico</i> by intercalating all of the first row transition metals (TMs) with boroxine-linked and triazine-linked COFs: COF-TM-x (where TM=Sc-Zn and x=3-5). This is a significant addition considering that only 187 experimentally COFs structures has been reported and characterized so far. We have investigated their structure and electronic properties. Specifically, we predict that COF's band gap and density of states (DOSs) can be controlled by intercalating first row transition metal atoms (TM: Sc - Zn) and fine tuned by the concentration of TMs. We also found that the $d$-subshell electron density of the TMs plays the main role in determining the electronic properties of the COFs. Thus intercalated-COFs provide a new strategy to control the electronic properties of materials within a porous network. This work opens up new avenues for the design of TM-intercalated materials with promising future applications in nanoporous electronic devices, where a high surface area coupled with fine-tuned electronic properties are desired.</div>

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

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