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Acid resistance enhancement of human tooth enamel surface by Nd:YAG laser and incorporating silver nanoparticles: in vitro study
摘要： Purpose This work was devoted to assess the use of Nd:YAG laser with and without nanosilver particles to enhance tooth resistance of dental enamel against carries. Method Forty-eight tooth samples were randomly divided into three main groups and received different treatments. Samples of group 1 were illuminated by a single pulse at different laser fluences, while those of group 2 received different number of laser pulses at fixed laser fluence, and finally the samples of group 3 received laser and colloidal silver nanoparticle treatments at different conditions. The samples were subjected to Vickers microhardness test, atomic force microscopy analysis, scanning electron microscopy observation, energy dispersive spectroscopy investigation, and demineralization and re-mineralization tests. Results Due to fast laser heating and quenching, a significant microhardness increase in the treated dental enamel samples was seen. This resulted in an improvement in the enamel resistance against acids because of the decrease in hydroxyapatite lattice stress and the reduction in enamel solubility. The addition of silver nanoparticles to the laser-treated enamel surface helped stabilize the granules of the enamel surface tissue under the effect of laser irradiation. The demineralization of laser-treated samples showed higher Ca/P ratios than control group, indicating a higher resistance against acids. Conclusion The combined laser illumination and the addition of silver nanoparticles lowered the tooth abrasion degree and increased tooth resistance to decay. The demineralized samples of all laser-treated samples had higher Ca/P ratios compared to the demineralized control sample. Laser energy has modified the Ca/P mineral ratio and forms steadier and lesser acid soluble compositions.
关键词： Nd:YAG laser,Tooth decay reduction,Demineralization rate,Dental enamel,Silver nanoparticles
更新于2025-09-11 14:15:04
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Manipulated interparticle gaps of silver nanoparticles by dendron-exfoliated reduced graphene oxide nanohybrids for SERS detection
摘要： We have successfully prepared a floating-typed surface-enhanced Raman scattering (SERS) substrate by the uniform nanoparticle arrays of silver nanoparticles (AgNPs) immobilized on the dendron-exfoliated reduced graphene oxide (rGO) nanosheets. These poly(urea/malonamide) dendrons were precisely synthesized, and then grafted on the dendron-exfoliated rGO nanosheets based on an efficient building block of dual functional 4-isocyanato-4′-(3,3-dimethyl-2,4-dioxo-azetidino)-diphenylmethane (IDD). By using dendron-rGO nanosheets as templates for hosting AgNPs, the particle size (D) and interparticle gap (W) of AgNPs could be manipulated by the incorporation of dendrons of various generations (0.5, 1.5, and 2.5 generations), evaluated by transmission electron microscopy. The results indicate that the nanohybrids with 1.5 generation-dendron exhibited stable, enormous, and linear-quantitative Raman enhancement in malachite green detection (1–100 ppm), due to the lowest W/D ratio (0.85 ± 0.60) and interparticle gap (7.60 ± 5.29 nm). The limit of detection (LOD) of malachite green is lower than 2.7 × 10?11 M (0.01 ppb). AgNPs@rGO-dendritic derivative nanohybrids as floating and flexible SERS substrates provide ultrasensitive and stable SERS detection in the solutions, which offers great potential for practical applications in detecting environmental pollutants.
关键词： Silver nanoparticles,Reduced graphene oxide nanosheets,Surface-enhanced Raman scattering detection,Dendritic polymers
更新于2025-09-11 14:15:04
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Single step formation of biocompatible bimetallic alloy nanoparticles of gold and silver using isonicotinylhydrazide
摘要： Manufacturing nanoparticles with controlled physicochemical properties using environment-friendly routes have potential to open new prospects for a variety of applications. Accordingly, several approaches have been established for manufacturing metal nanoparticles. Many of these approaches entail the use of hazardous chemicals and could be toxic to the environment, and cannot be used readily for biomedical applications. In the present work, we report a single step bio-friendly approach to formulate gold (Au), silver (Ag), and Au-Ag alloy nanoparticles with desired surface corona and composition isonicotinylhydrazide (INH) as a reducing agent. INH also functioned as a stabilizing agent by enabling a surface corona around the nanoparticles. Remarkably, within a single step INH could also provide a handle in regulating the composition of Au and Ag in bimetallic systems without any additional chemical modification. The physicochemical and surface properties of the different nanoparticles thus obtained have been examined by analytical, spectroscopic and microscopic techniques. Cell cytotoxicity (release of lactate dehydrogenase), cell viability and intracellular reactive oxygen species (ROS) assays confirmed that the Au, Ag, and Au-Ag bimetallic nanoparticles prepared with INH are biocompatible. Finally, the presence of organic surface corona of INH on the nanoparticles was found to impart peroxidase enzyme-like activity and antimycobacterial sensitivity to the nanoparticles.
关键词： enzyme-like,physicochemical,Gold-silver nanoparticles,antimycobacterial,isonicotinylhydrazide,biocompatible
更新于2025-09-11 14:15:04
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Fabrication of Luminescent Antireflective Coatings with CaMoO4:Eu3+/Ag Composite Structure
摘要： Highly transparent and luminescent CaMoO4:Eu3+/Ag composite films were fabricated on glass substrates as multifunctional antireflective (AR) coatings. The films were deposited through a combination of a sol–gel dip-coating technique and a hot water treatment. With the addition of an aluminum source in coating solutions, the sol–gel-derived films underwent a remarkable microstructural change during the hot water treatment due to the reaction between an amorphous alumina phase and water. This change brought both an antireflective effect (suppression of Fresnel reflection) and luminescence enhancement (suppression of total internal reflection) to the films. The introduction of Ag nanoparticles into the films further increased luminescence intensity without losing the antireflective effect.
关键词： calcium molybdate,silver nanoparticles,antireflective coatings,europium,nanocomposite,sol–gel method,photoluminescence
更新于2025-09-11 14:12:44
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Synthesis of silver nanoparticles by atmospheric-pressure pulsed discharge plasma in a slug flow system
摘要： Application of nonequilibrium atmospheric-pressure plasma has been proven as a medium for silver particle formation in slug flow reactor systems. Argon gas was introduced in the slug flow reactor system in the gas phase. In the liquid phase, silver nitrate (AgNO3) with and without the addition of starch was dissolved in distilled water. The flow rates of the liquid and gas phases were 1.5 and 0.15 ml min?1, respectively. A yellow-colored solution product was obtained when the feed solution containing starch was fed. The optical emission spectrum showed that silver atoms were detected clearly at 328 nm. The ultraviolet–visible spectroscopy analysis showed that the solution products seemed to absorb light between 380 and 440 nm, corresponding to silver nanoparticle generation. Transmission electron microscopy revealed that the monodispersed silver nanoparticles were formed in a spherical morphology with diameter less than 10 nm on average. ? 2018 The Japan Society of Applied Physics
关键词： atmospheric-pressure pulsed discharge plasma,starch,silver nitrate,silver nanoparticles,slug flow system
更新于2025-09-10 09:29:36
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Electrospinning 3D Nanofiber Structure of Polycaprolactone Incorporated with Silver Nanoparticles
摘要： This study presents a one-station 3D fabrication technique of nano?brous scaffold for tissue engineering. A divergence static electric ?eld was introduced in an electrospinning system to induce a self-assembly of aligned polycaprolactone (PCL) nano?bers into a tunable 3D architecture with thickness ranging from 2 to 12 mm. Silver nanoparticles were incorporated into the PCL solution to alter the electrical conductivity. Human ?broblast cells were cultured on the pure PCL nano?ber scaffolds in vitro for 7 days. It was found that the occurrence of nano?ber bridging phenomenon depended on the solution viscosity. The minimum viscosity to form a 3D nano?ber structure was higher than that to form a 2D nano?ber mat. The homogeneity of nano?ber distribution within the 3D space was positively correlated with the electrical conductivity and the weight of the nano?bers. In the cell culture test, ?broblasts proliferated on the scaffold and organized as an aligned matrix which mimicked the microstructure of native musculoskeletal tissues.
关键词： Tissue engineering,3D nano?ber structure,Electrospinning,Polycaprolactone,Silver nanoparticles
更新于2025-09-10 09:29:36
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Optical and Photoacoustic Properties of Colloidal Silver Nanoparticles Solutions
摘要： The study has aimed to investigate optical and photoacoustic properties of some colloidal silver nanoparticles at different concentration over the time. The phase purity with crystal structure of silver nanoparticles were studied using X-ray diffraction (XRD) and was confirmed by Transmission Electron Microscopy (TEM). Optical property was changed during the variable concentration of nanoparticles and duration time of sample. The absorbance of silver colloidal solutions is increased, when concentration increases but decreased with respective to the longer period of sample. Absorption peaks and stability of particles in solutions is influenced by the duration time of solution and its concentration. The low concentration-based solutions fall in the absorbance over the times. The observed PA signal is subjected by the factor of parameters; such as, pump wavelengths, energy, repetition rate, concentrations, and temperature. Stability of fluorescence and absorption peaks are influenced by the concentration of particles and time period of colloidal solution. Effects on PA signal with fluorescent and absorption peaks upon the concentration was also significant.
关键词： silver nanoparticles,photoluminescence,photoacoustic,absorption
更新于2025-09-10 09:29:36
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A field-deployable surface-enhanced Raman scattering (SERS) method for sensitive analysis of silver nanoparticles in environmental waters
摘要： The proliferation of silver nanoparticles (AgNPs) in the environment and resultant transport into aquatic systems have raised concerns regarding their potential toxicity to various organisms. These environmental and ecological concerns demand reliable AgNP detection methods which can measure environmentally relevant quantities of AgNPs in real aquatic systems. This study developed a method that couples a rapid vacuum filtration technique with a portable Raman spectrometer to achieve on-site detection of ultra-low levels of AgNPs in typical and complex aquatic systems. To extract and detect AgNPs, aluminum chloride and ferbam were added for AgNP aggregation and labelling, respectively. The AgNP aggregates were filtered through a membrane, and their presence and quantity were determined based upon the surface-enhanced Raman scattering (SERS) peak intensity of ferbam. Under the optimized conditions, the extraction efficiencies are 99 ± 0.001% in ultrapure water and 98 ± 0.025% in marine water for 1 mg/L AgNPs. This method enables simple volume adjustment and improves the consistency of AgNP distribution on the membrane. The performance of the method was evaluated in different environmental waters, including marine water, fresh waters (pond water, river water, and reservoir outlet water) and drinking waters (municipal tap water and well water), with highest signal intensity in marine water and lowest signals in fresh waters. The signal intensity difference was suggested to be caused by the amount of natural organic matter (NOM) in these environmental waters. Using pond water as an example, the interference was minimized by changing the aggregating salt from AlCl3 to MgCl2, and AgNPs as low as 5 μg/L were reliably detected with a volume of 100 mL. At the same volume, the developed method was sensitive enough to detect 1 μg/L AgNPs in marine water and also holds promise for assessing the time-dependent transformation of AgNPs.
关键词： Silver nanoparticles (AgNPs),Portable method,Environmental waters,Surface-enhanced Raman spectroscopy (SERS)
更新于2025-09-10 09:29:36
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EXTRACELLULAR AND INTRACELLULAR SYNTHESIS OF SILVER NANOPARTICLES
摘要： The cellular synthesis of nanoparticle is a green process and alternative for a conventional process for the preparation of silver nanoparticles. In our research, focus has been given to the development of an efficient and eco-friendly viable process for the synthesis of silver nanoparticles using cancer and non-cancerous cells, a cell culture that was isolated. The results of this investigation are observed that silver nanoparticles could be induced to synthesis intra- and extra-cellularly using mammalian cells such as cancerous and non-cancerous cells. The silver nanoparticles are synthesized by the cancer and non-cancerous cells such as HeLa (Homo sapiens, human), SiHa, and human embryonic kidney-293 cell lines. The silver nanoparticles were characterized by ultraviolet (UV)-visible spectroscopy, transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). The silver nanoparticles exhibited maximum absorbance at 415 nm in UV-visible spectroscopy. The XRD confirms the characteristic of the crystal lattice of silver nanoparticles by observing three peaks: Peak at 38 is due to reflection from (111), peak at 44 is due to reflection from (200), and peak at 65 is due to reflection from (220). TEM images showed the formation of stable silver nanoparticles in the cell lines. The method of extraction of intracellular/extracellular synthesis of silver nanoparticles was inexpensive, simple, and effective in large scale with no need to use of complex process equipment. The cancer cell considered as a biological factory at nanoscale dimension which continued to grow after synthesis of silver nanoparticles. The silver reduction by these cancer cells has occurred through energy-dependent processes that lead to the high output of this reaction. Hence, this new approach of using a mammalian cell for the successful synthesis of nanosized silvers could be easily scaled up, which establishes its commercial viability and also useful in the drug delivery and drug targeting.
关键词： Cancer cells,Biosynthesis and characteristics of silver nanoparticles,Silver nanoparticles
更新于2025-09-09 09:28:46
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Preyssler-based nanocomposite as a magnetic photocatalyst: synthesis, characterisation and its photocatalytic activity for decolourisation of rhodamine B
摘要： In this work, the authors prepared a novel magnetic photocatalyst by grafting of Preyssler-type polyoxometalate, H14 [NaP5 W30 O110] onto Fe3O4 nanoparticles via an internal layer of silver nanoparticles. The obtained nanocomposite has been characterised by electron dispersive X-ray, transmission electron microscopy and scanning electron microscopy. The activity of the synthesised nanomagnetic photocatalyst was tested by the photocatalytic decolourisation of rhodamine B under UV light irradiation in the study’s designed reactor. It was found that, compared to pure Preyssler, decolourisation of rhodamine B was occurred four times faster using the synthesised magnetic nanocomposite with easy separation. The magnetic nanocatalyst was separated after ending the reaction and recycled. It just showed 2–3% decrease in catalytic activity after four recycling.
关键词： Preyssler-type polyoxometalate,Fe3O4 nanoparticles,photocatalytic decolourisation,rhodamine B,magnetic photocatalyst,silver nanoparticles
更新于2025-09-09 09:28:46