scholarly journals Fluorescent Silver Nanoclusters Embedded in Hydrogel Matrix and Its Potential Use in Environmental Monitoring

2021 ◽  
Vol 11 (8) ◽  
pp. 3470
Author(s):  
Luca Burratti ◽  
Fabio De Matteis ◽  
Roberto Francini ◽  
Joohyun Lim ◽  
Christina Scheu ◽  
...  
Keyword(s):  
Solid State ◽  
Optical Sensors ◽  
Silver Nanoclusters ◽  
Photochemical Synthesis ◽  
Glycol Diacrylate ◽  
Transmission Electron ◽  
Hydrogel Matrix ◽  
Bio Imaging ◽  
Poly Ethylene ◽  
Application Fields

The optical absorption and fluorescence of silver nanoclusters (AgNCs) are widely exploited in many different application fields such as sensors, bio-imaging, drug delivery, etc. In the sensor field, optical devices are highly versatile thanks to their ease of fabrication and low costs and, therefore, are optimal candidates to replace expensive apparatuses commonly used. In this study, we synthesized AgNCs in aqueous phase by photochemical synthesis using poly methacrylic acid (PMAA) as a stabilizer. Colloidal water solutions of these NCs showed a very good sensitivity to Pb(II) ions, and in order to fabricate a solid-state sensor, we introduced them in a hydrogel material formed by poly(ethylene glycol) diacrylate with a molecular weight of 700 g/mol (PEGDA700). The systems were characterized using absorption and fluorescence spectroscopy and transmission electron microscopy (TEM). Finally, the sensitivity to Pb(II) ions has been tested with the aim to use these systems as solid-state optical sensors for water quality.

Synthesis of Fluorescent Ag Nanoclusters for Sensing and Imaging Applications

2018 ◽  
Vol 941 ◽  
pp. 2243-2248 ◽  
Author(s):  
Luca Burratti ◽  
Eleonora Bolli ◽  
Mauro Casalboni ◽  
Fabio de Matteis ◽  
Federico Mochi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Sensors ◽  
Bulk Material ◽  
Energy Levels ◽  
Silver Nanoclusters ◽  
Absorption Bands ◽  
Discrete Energy ◽  
Quantum Size ◽  
Transmission Electron ◽  
Bio Imaging

Metal nanoparticles have attracted more and more attention in the last years due to their unique chemical and physical properties which are very different from the metal bulk material. In particular, when the size of nanoparticles decreases below two nm, nanoparticles can be described as nanoclusters (NCs), and they present peculiar optical properties. The excited electrons in addition to specific absorption bands show also a bright luminescence related to the quantum size effect which produce discrete energy levels. Optical properties (absorption and fluorescence) of these NCs are widely used in many different applications in science and engineering, such as chemical sensors, fluorescent probes for bio imaging or in environmental issues. In the present study, we report on the synthesis of silver nanoclusters (AgNCs) in aqueous phase using silver nitrate as precursor salt and L-Glutathione (GSH) as stabilizer. AgNCs were characterized using absorption and fluorescence spectroscopy, and transmission electron microscopy (TEM). The strong absorption and luminescence shown by these NCs are very promising for a possible exploitation both as label for bioimaging and for optical sensors for heavy metal ions.

scholarly journals Composite Nanogels Based on Zeolite-Poly(ethylene glycol) Diacrylate for Controlled Drug Delivery

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 195 ◽  
Author(s):  
Catalina Paula Spatarelu ◽  
Anita-Laura (Radu) Chiriac ◽  
Bogdan Cursaru ◽  
Tanta-Verona Iordache ◽  
Ana-Mihaela Gavrila ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Ethylene Glycol ◽  
Natural Zeolite ◽  
Drug Loading ◽  
Controlled Drug Delivery ◽  
Poly Ethylene Glycol ◽  
Glycol Diacrylate ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Poly Ethylene

This study presents the design of novel composites nanogels, based on poly(ethylene glycol) diacrylate and natural zeolite particles, that are able to act as materials with controlled drug delivery properties. Natural zeolite–nanogels composite, with varying zeolite contents, were obtained by an inverse mini-emulsion technique and loaded with 5-fluorouracil, a widely used chemotherapeutic drug. Herein, the possibility of adjusting final properties by means of modifying the preparation conditions was investigated. The prepared composite nanogels are characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). In light of this tunable drug-loading capability, swelling behaviour, and cytotoxicity, these composite nanogels could be highly attractive as drug reservoirs.

Poly(ethylene Glycol) Diacrylate-Nanogels Synthesized by Mini-emulsion Polymerization

2019 ◽  
Vol 56 (3) ◽  
pp. 514-519
Author(s):  
Anita Laura Radu ◽  
Ana Mihaela Gavrila ◽  
Bogdan Cursaru ◽  
Catalina Paula Spatarelu ◽  
Teodor Sandu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ethylene Glycol ◽  
Biomedical Applications ◽  
Gel Permeation Chromatography ◽  
Poly Ethylene Glycol ◽  
Glycol Diacrylate ◽  
Synthesis Parameters ◽  
Transmission Electron ◽  
Hydrophilic Lipophilic Balance ◽  
Poly Ethylene

New nanogels (NGs) with tailored properties were obtained using a mini-emulsion technique, from poly(ethylene glycol) diacrylate (PEGDA) self-crosslinking macromers of various molecular weight. By modifying synthesis parameters (hydrophilic-lipophilic balance, emulsifier and the ratio of organic-aqueous medium), optimum recipes of NGs were selected. Therefore, the molecular weight distribution and the functionalization degree of the PEGDA2000 macromer were assessed by Gel Permeation Chromatography (GPC) and Nuclear Magnetic Resonance (NMR), respectively. Furthermore, the PEGDA-NGs were investigated by Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) for size distributions and morphology. DLS and TEM results confirm that these new PEGDA-NGs hold potential for biomedical applications.

scholarly journals A Combined Approach of Double Network Hydrogel and Nanocomposites Based on Hyaluronic Acid and Poly(ethylene glycol) Diacrylate Blend

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2454 ◽  
Author(s):  
Alfredo Ronca ◽  
Ugo D’Amora ◽  
Maria Raucci ◽  
Hai Lin ◽  
Yujiang Fan ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Ethylene Glycol ◽  
Sol Gel ◽  
Poly Ethylene Glycol ◽  
Double Network ◽  
Glycol Diacrylate ◽  
Physico Chemical ◽  
Hydrogel Matrix ◽  
Poly Ethylene ◽  
Sol Gel Synthesis

In this study, an innovative polymer blend, based on double network (DN) approach, has been developed by integrating a poly(ethylene glycol) diacrylate (PEGDA) network into a chemically modified hyaluronic acid sodium salt (HAs) hydrogel matrix. Here, the HAs was chemically functionalized with photocrosslinkable moieties by reacting with maleic anhydride (MAA) to obtain a maleated hyaluronic acid (MaHA). Furthermore, nanocomposite DN hydrogels were suitably prepared by physical blending of hydroxyapatite nanoparticles (HAp), obtained by sol-gel synthesis, within the hydrogel. Physico-chemical, thermal, morphological and mechanical analyses were performed. Results showed enhanced mechanical properties and a homogenous microstructure as highlighted by mechanical and morphological investigations. This suggests that nanocomposite DN hydrogels are promising candidates for biomedical applications.

Micropatterning of Poly (Ethylene Glycol)-Diacrylate (PEG-DA) Hydrogel by Soft-Photolithography for Analysis of Cell-Biomaterial Interactions

2009 ◽  
Vol 2 ◽  
pp. 3-14 ◽  
Author(s):  
Karthikeyan Subramani ◽  
M.A. Birch
Keyword(s):  
Ethylene Glycol ◽  
Three Dimensional ◽  
Poly Ethylene Glycol ◽  
Contact Printing ◽  
Pdms Stamp ◽  
Glycol Diacrylate ◽  
Dimethyl Siloxane ◽  
Hydrogel Matrix ◽  
Poly Ethylene ◽  
Innovative Techniques

Poly (ethylene glycol) hydrogel (PEG) micropatterns fabricated by photolithography and various other microfabrication techniques have been used as a platform to analyze cell-biomaterial interactions in cell culture studies. Numerous innovative techniques have been described about photolithography and the use of Poly (dimethyl siloxane) stamp (PDMS) based pressure moulding technique for the microfabrication of PEG hydrogel micropatterns. We herein this literature describe a simple and a versatile method for fabricating Poly (ethylene glycol) hydrogel-diacrylate (PEG-DA) hydrogel micropatterns using the ‘Soft-photolithography’ technique which is a combination of pressure moulding using a PDMS stamp and photolithography. Using this simple technique, PEG-DA hydrogel micropatterns were fabricated on a silicon substrate of varying dimensions from 40μm to 10μm within the same substrate. Such a three-dimensional microenvironment with varying sizes can serve as an excellent platform to study cell behaviour in culture. These PEG-DA hydrogel micropatterns can further be functionalized by adding a variety of biomolecular cues within the PEG-DA hydrogel matrix or these biomolecules can be patterned on the PEG-DA micropatterns after photopolymerization using micro-contact printing for analysis of cell-biomaterial interactions and tissue engineering purposes.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

Transmission Electron Microscopy of an Aluminum-Silver-Stainless Steel Solid State Bond

1985 ◽  
Vol 43 ◽  
pp. 172-173
Author(s):  
M. J. Carr ◽  
J. F. Shewbridge ◽  
T. O. Wilford
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Specimen Preparation ◽  
Dimensional Control ◽  
Tem Analysis ◽  
Metal Parts ◽  
Dissimilar Metal ◽  
Transmission Electron ◽  
Short Time

Strong solid state bonds are routinely produced between physical vapor deposited (PVD) silver coatings deposited on sputter cleaned surfaces of two dissimilar metal parts. The low temperature (200°C) and short time (10 min) used in the bonding cycle are advantageous from the standpoint of productivity and dimensional control. These conditions unfortunately produce no microstructural changes at or near the interface that are detectable by optical, SEM, or microprobe examination. Microstructural problems arising at these interfaces could therefore easily go undetected by these techniques. TEM analysis has not been previously applied to this problem because of the difficulty in specimen preparation. The purpose of this paper is to describe our technique for preparing specimens from solid state bonds and to present our initial observations of the microstructural details of such bonds.

Observation of solid-state reaction between a thin yttria film and a (0001) α-alumina substrate

1994 ◽  
Vol 52 ◽  
pp. 644-645
Author(s):  
J. R. Heffelfinger ◽  
C. B. Carter
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Solid State Reaction ◽  
Yttrium Aluminum Garnet ◽  
Secondary Phase ◽  
Ceramic Composites ◽  
Alumina Substrate ◽  
Transmission Electron ◽  
Alumina Fibers ◽  
Optical Applications

Transmission-electron microscopy (TEM), scanning-electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were used to investigate the solid-state reaction between a thin yttria film and a (0001) α-alumina substrate. Systems containing Y2O3 (yttria) and Al2O3 (alumina) are seen in many technologically relevant applications. For example, yttria is being explored as a coating material for alumina fibers for metal-ceramic composites. The coating serves as a diffusion barrier and protects the alumina fiber from reacting with the metal matrix. With sufficient time and temperature, yttria in contact with alumina will react to form one or a combination of phases shown by the phase diagram in Figure l. Of the reaction phases, yttrium aluminum garnet (YAG) is used as a material for lasers and other optical applications. In a different application, YAG is formed as a secondary phase in the sintering of AIN. Yttria is added to AIN as a sintering aid and acts as an oxygen getter by reacting with the alumina in AIN to form YAG.

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