scholarly journals UV Treatment of the Stabilizing Shell for Improving the Photostability of Silver Nanoparticles

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Silvia Rinaldi ◽  
Luigi Tarpani ◽  
Loredana Latterini
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Laser Scanning ◽  
Prolonged Exposure ◽  
Uv Light ◽  
Light Exposure ◽  
Uv Curing ◽  
Laser Scanning Microscopy ◽  
Localized Surface Plasmon ◽  
Confocal Laser

Silver nanoparticles or nanoclusters are quite sensitive to light exposure. In particular, irradiation in the localized surface plasmon resonance (LSPR) region brings about a drastic modification of their optical properties due to growth and reshaping of the nanoparticles. In order to obtain luminescent colloids, small silver colloidal nanoparticles were prepared in chloroform using vinylpyrrolidone oligomers as capping agent and their luminescence properties were used to control their stability upon prolonged exposure to visible light. The polymeric shell around the metal clusters was hardened through photo-cross-linking by UV light. This process did not alter the morphology and the optical properties of the nanoparticles but greatly improved the particle photostability as confirmed also by confocal laser scanning microscopy measurements. The data clearly show that UV curing of the stabilizing layer could be a simple postsynthetic procedure to obtain materials with stable properties.

scholarly journals Silver Nanoparticles Formation by Jatropha integerrima and LC/MS-QTOF-Based Metabolite Profiling

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2400
Author(s):  
Afrah E. Mohammed ◽  
Lamya Ahmed Al-Keridis ◽  
Ishrat Rahman ◽  
Modhi O. Alotaibi ◽  
Rasha Saad Suliman ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Laser Scanning ◽  
Antibacterial Effect ◽  
Therapeutic Potential ◽  
Laser Scanning Microscopy ◽  
Ultrastructural Changes ◽  
Confocal Laser ◽  
Synthesis Methods ◽  
Tem Analysis ◽  
Average Size

The broad application of metal nanoparticles in different fields encourages scientists to find alternatives to conventional synthesis methods to reduce negative environmental impacts. Herein, we described a safe method for preparing silver nanoparticles (J-AgNPs) using Jatropha integerrima leaves extract as a reducing agent and further characterize its physiochemical and pharmacological properties to identify its therapeutic potential as a cytotoxic and antimicrobial agent. The biogenic synthesized J-AgNPs were physiochemically characterized by ultraviolet-visible spectroscopy, dynamic light scattering (DLS), transmission electron microscope (TEM), and energy-dispersive X-ray spectroscopy. HPLC-DAD, followed by LC/MS and the Fourier-transform infrared spectroscopy (FTIR), was applied to detect the biomolecules of J. integerrima involved in the fabrication of NPs. Furthermore, J-AgNPs and the ampicillin-nanocomposite conjugate were investigated for their potential antibacterial effects against four clinical isolates. Finally, cytotoxic effects were also investigated against cancer and normal cell lines, and their mechanism was assessed using TEM analysis and confocal laser scanning microscopy (LSM). Ag ions were reduced to spherical J-AgNPs, with a zeta potential of −34.7 mV as well as an average size of 91.2 and 22.8 nm as detected by DLS and TEM, respectively. HPLC GC/MC analysis identified five biomolecules, and FTIR suggested the presence of proteins besides polyphenolic molecules; together, these molecules could be responsible for the reduction and capping processes during NP formation. Additionally, J-AgNPs displayed a strong antibacterial effect, although the ampicillin conjugated form had a very weak antibacterial effect. Furthermore, the NPs caused a reduction in cell viability of all the treated cells by initiating ultrastructural changes and apoptosis, as identified by TEM and LSM analysis. Therefore, J-AgNPs can be formed using the leaf extract from the J. integerrima plant. Furthermore, J-AgNPs may serve as a candidate for further biochemical and pharmacological testing to identify its therapeutic value.

scholarly journals Two-Sided Antibacterial Cellulose Combining Probiotics and Silver Nanoparticles

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2848
Author(s):  
Laura Sabio ◽  
Andrea Sosa ◽  
José M. Delgado-López ◽  
José M. Dominguez-Vera
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Infections ◽  
Laser Scanning ◽  
Opportunistic Pathogen ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Resistant Bacteria ◽  
Skin Infections ◽  
Antibiotic Resistant ◽  
Promising Strategy

The constant increase of antibiotic-resistant bacteria demands the design of novel antibiotic-free materials. The combination of antibacterials in a biocompatible biomaterial is a very promising strategy to treat infections caused by a broader spectrum of resistant pathogens. Here, we combined two antibacterials, silver nanoparticles (AgNPs) and living probiotics (Lactobacillus fermentum, Lf), using bacterial cellulose (BC) as scaffold. By controlling the loading of each antibacterial at opposite BC sides, we obtained a two-sided biomaterial (AgNP-BC-Lf) with a high density of alive and metabolically active probiotics on one surface and AgNPs on the opposite one, being probiotics well preserved from the killer effect of AgNPs. The resulting two-sided biomaterial was characterized by Field-Emission Scanning Electron Microscopy (FESEM) and Confocal Laser Scanning Microscopy (CLSM). The antibacterial capacity against Pseudomonas aeruginosa (PA), an opportunistic pathogen responsible for a broad range of skin infections, was also assessed by agar diffusion tests in pathogen-favorable media. Results showed an enhanced activity against PA when both antibacterials were combined into BC (AgNP-BC-Lf) with respect to BC containing only one of the antibacterials, BC-Lf or AgNP-BC. Therefore, AgNP-BC-Lf is an antibiotic-free biomaterial that can be useful for the therapy of topical bacterial infections.

scholarly journals Taxon- and senescence-specific fluorescence of colored leaves from the Pliocene Willershausen Lagerstätte, Germany

PalZ ◽  
2021 ◽  
Author(s):  
Klaus Wolkenstein ◽  
Gernot Arp
Keyword(s):  
Laser Scanning ◽  
Uv Light ◽  
Degradation Products ◽  
Emission Spectra ◽  
Plant Macrofossils ◽  
Laser Scanning Microscopy ◽  
Fluorescence Properties ◽  
Confocal Laser ◽  
Lower Saxony ◽  
Coal Macerals

AbstractUV-light-induced fluorescence is widely used in the study of coal macerals and palynological samples, but to date has not been described in great detail for plant macrofossils. Here, we report the characteristics of bright UV-light-induced fluorescence of various fossil angiosperm leaf taxa from the Upper Pliocene of Willershausen, Lower Saxony, Germany. The fluorescence is exceptional, since different fluorescence colors ranging from green to yellow to red can be observed and fluorescence properties are found to be related to genera. Using confocal laser scanning microscopy, fluorescence was studied in detail and emission spectra were obtained that allowed to differentiate broad groups of fluorophores. Fluorescence emissions attributed to chlorophyll degradation products demonstrate that fluorescence can be used as an indicator for exceptional chemical preservation of leaf fossils. Comparison with present-day senescing plants suggests that the fluorescence differences in the fossil leaves are mainly caused by taxon-specific degeneration of organic compounds during senescence. The occurrence of various leaf taxa with different fluorescence properties, preserved under identical conditions of fossilization, indicate that diagenesis was not crucial for the differences in leaf fluorescence.

scholarly journals Antibacterial Photodynamic Inactivation of Fagopyrin F from Tartary Buckwheat (Fagopyrum tataricum) Flower against Streptococcus mutans and Its Biofilm

2021 ◽  
Vol 22 (12) ◽  
pp. 6205
Author(s):  
Jaecheol Kim ◽  
Suna Kim ◽  
Kiuk Lee ◽  
Ryun Hee Kim ◽  
Keum Taek Hwang
Keyword(s):  
Streptococcus Mutans ◽  
Laser Scanning ◽  
Light Exposure ◽  
Laser Scanning Microscopy ◽  
Tartary Buckwheat ◽  
Plate Count ◽  
Confocal Laser ◽  
Light Sources ◽  
Photodynamic Inactivation ◽  
Fagopyrum Tataricum

The objective of this study was to determine reactive oxygen species (ROS) produced by fagopyrin F-rich fraction (FFF) separated from Tartary buckwheat flower extract exposed to lights and to investigate its antibacterial photodynamic inactivation (PDI) against Streptococcus mutans and its biofilm. ROS producing mechanisms involving FFF with light exposure were determined using a spectrophotometer and a fluorometer. S. mutans and its biofilm inactivation after PDI treatment of FFF using blue light (BL; 450 nm) were determined by plate count method and crystal violet assay, respectively. The biofilm destruction by ROS produced from FFF after exposure to BL was visualized using confocal laser scanning microscopy (CLSM) and field emission scanning electron microscope (FE-SEM). BL among 3 light sources produced type 1 ROS the most when applying FFF as a photosensitizer. FFF exposed to BL (5 and 10 J/cm2) significantly more inhibited S. mutans viability and biofilm formation than FFF without the light exposure (p < 0.05). In the PDI of FFF exposed to BL (10 J/cm2), an apparent destruction of S. mutans and its biofilm were observed by the CLSM and FE-SEM. Antibacterial PDI effect of FFF was determined for the first time in this study.

scholarly journals Ultraviolet Light Induces Apoptosis via Direct Activation of CD95 (Fas/APO-1) Independently of Its Ligand CD95L

1998 ◽  
Vol 140 (1) ◽  
pp. 171-182 ◽  
Author(s):  
Yoshinori Aragane ◽  
Dagmar Kulms ◽  
Dieter Metze ◽  
Gabriele Wilkes ◽  
Birgit Pöppelmann ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Uv Light ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Critical Event ◽  
Hacat Cells ◽  
Death Domain ◽  
Natural Ligand ◽  
Keratinocyte Cell Line Hacat ◽  
Induced Apoptosis

Induction of apoptosis in keratinocytes by UV light is a critical event in photocarcinogenesis. Although p53 is of importance in this process, evidence exists that other pathways play a role as well. Therefore, we studied whether the apoptosis-related surface molecule CD95 (Fas/APO-1) is involved. The human keratinocyte cell line HaCaT expresses CD95 and undergoes apoptosis after treatment with UV light or with the ligand of CD95 (CD95L). Incubation with a neutralizing CD95 antibody completely prevented CD95L-induced apoptosis but not UV-induced apoptosis, initially suggesting that the CD95 pathway may not be involved. However, the protease CPP32, a downstream molecule of the CD95 pathway, was activated in UV-exposed HaCaT cells, and UV-induced apoptosis was blocked by the ICE protease inhibitor zVAD, implying that at least similar downstream events are involved in CD95- and UV-induced apoptosis. Activation of CD95 results in recruitment of the Fas-associated protein with death domain (FADD) that activates ICE proteases. Immunoprecipitation of UV-exposed HaCaT cells revealed that UV light also induces recruitment of FADD to CD95. Since neutralizing anti-CD95 antibodies failed to prevent UV-induced apoptosis, this suggested that UV light directly activates CD95 independently of the ligand CD95L. Confocal laser scanning microscopy showed that UV light induced clustering of CD95 in the same fashion as CD95L. Prevention of UV-induced CD95 clustering by irradiating cells at 10°C was associated with a significantly reduced death rate. Together, these data indicate that UV light directly stimulates CD95 and thereby activates the CD95 pathway to induce apoptosis independently of the natural ligand CD95L. These findings further support the concept that UV light can affect targets at the plasma membrane, thereby even inducing apoptosis.

scholarly journals Efficacy of diode laser and sonic agitation of Chlorhexidine and Silver-nanoparticles in infected root canals

2020 ◽  
Vol 23 (3) ◽  
Author(s):  
Latifa Mohamed Abdelgawad ◽  
Niven Asmail ◽  
Somia Abdel Latif ◽  
Ali Mohamed Safaan
Keyword(s):  
Silver Nanoparticles ◽  
Diode Laser ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Root Canals ◽  
Infected Root ◽  
Study Results ◽  
Significant Difference ◽  
Group 2

Objective: To assess the efficacy of agitation of chlorohexidine (CHX) and Silver nanoparticles “AgNps” with 810nm diode laser or sonic endoactivator compared to side –vented needle on infected root canals with Enterococcus “E” Faecalis biofilms. Material and Methods: Sixty-five extracted human premolars with single oval canals were instrumented by protaper system up to F3. Biofilms of E. faecalis were generated based on a previously established protocol. Two teeth were used to check the biofilm formation, then the remaining Teeth were randomly divided into three equal experimental groups according to agitation techniques used: group 1 (810 nm diode laser with 1 watt), group 2 (sonic endoactivator) and group 3 (Side vented needle). Each group was further divided into three equal subgroups according to the irrigant solution into; subgroup A: chlorohexidine, subgroup B: silver nanoparticles and subgroup C: distilled water: Confocal laser scanning microscopy “CLSM” was used to assess bacterial viability. Data were analyzed by appropriate statistical analyses with P = 0.05. Results: Regarding the activation method, all groups had a significantly high percentage of dead bacteria (P < 0.05). However, Laser was significantly the highest and Endoactivator the least (P < = 0.001). Diode laser agitation of AgNps irrigant showed the highest reduction percentage of bacteria (78.1%) with a significant difference with both CHX and water irrigation, Conclusion: Under the condition of the present study; results reinforced that laser activation is a useful adjunct, 810 nm diode laser agitation of AgNps or chlorhexidine was more effective in disinfection of oval root canals than endoactivator and side vented needle techniques.KeywordsDentinal infection; Silver-nanoparticles; chlorohexidine; agitation; Diode Laser; Sonic endoactivator. 

Detecting exodermal Casparian bands in vivo and fluid-phase endocytosis in onion (Allium cepa L.) roots

2001 ◽  
Vol 79 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Ewa Cholewa ◽  
Carol A Peterson
Keyword(s):  
Laser Scanning ◽  
Uv Light ◽  
Fluid Phase ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Running Water ◽  
Casparian Bands ◽  
Fluid Phase Endocytosis ◽  
Casparian Band

Maturation of the exodermis involves development of a Casparian band, a structure that blocks the apoplastic movement of ions. The position at which this band is formed is not readily predictable, since it depends on species and growing conditions. Until now, Casparian band detection necessitated destructive methods which involved sectioning or clearing the roots. In the present study, a method for detecting exodermal Casparian bands in vivo is presented. Undisturbed onion roots were incubated for 2 h in 0.1% 8-hydroxy-1,3,6-pyrenetrisulphonate (PTS) and then thoroughly rinsed in running water. Under UV light, the tracer was evident in the cortex of the root regions with an immature exodermis but not in older regions of the root where the Casparian band had developed. PTS had entered the protoplasts of the cortical cells in the younger part of the root and had not been removed by rinsing. The first order kinetics of uptake, and insensitivity to external pH and probenecid indicated that PTS entered the cell by fluid-phase endocytosis. PTS-loaded vesicles that released their contents into the vacuole were seen using confocal laser scanning microscopy. When applied to undisturbed, whole root systems, PTS was not detected in aqueous extracts of the leaves. Thus, there is no major apoplastic bypass in healthy onion roots.Key words: exodermis, Casparian bands, apoplastic bypass, PTS, fluid-phase endocytosis.

scholarly journals Fluorescence lifetime imaging of red yeast Cystofilobasidium capitatum during growth

2018 ◽  
Vol 2 (2) ◽  
pp. 114-120 ◽  
Author(s):  
Martin Vanek ◽  
Filip Mravec ◽  
Martin Szotkowski ◽  
Dana Byrtusova ◽  
Andrea Haronikova ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Laser Scanning ◽  
Light Exposure ◽  
Laser Scanning Microscopy ◽  
Model Systems ◽  
Confocal Laser ◽  
Fluorescence Lifetime Imaging ◽  
Lifetime Imaging ◽  
Red Yeast

AbstractRed yeast Cystofilobasidium capitatum autofluorescence was studied by means of confocal laser scanning microscopy (CLSM) to reveal distribution of carotenoids inside the cells. Yeasts were cultivated in 2L fermentor on glucose medium at permanent light exposure and aeration. Samples were collected at different times for CLSM, gravimetric determination of biomass and HPLC determination of pigments. To compare FLIM (Fluorescence Lifetime Imaging Microscopy) images and coupled data (obtained by CLSM) with model systems, FLIM analysis was performed on micelles of SDS:ergosterol and SDS:coenzyme Q with different content of ergosterol and coenzyme Q, respectively, and with constant addition of beta-carotene. Liposomes lecithin:ergosterol:beta-carotene were investigated too. Two different intracellular forms of carotenoids were observed during most of cultivations, with third form appeared at the beginning of stationary phase. Observed behavior is probably due to formation of some kind of carotenoid protective system in membranes of different compartments of yeast cell, especially cytoplasmic membrane.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

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