Deposition Of Silver Nanoparticles Research Articles

In-situ deposition of silver nanoparticles onto glass by non-thermal plasma jet

In-situ deposition of silver nanoparticles onto glass by non-thermal plasma jet

Detection of water pollutants using super-hydrophobic porous silicon-based SERS substrates.

Super hydrophobic porous silicon surface is prepared using a wet chemical synthesis route. Scanning electron microscopic investigation confirms a correlation between pore size and reaction time. SERS substrates are prepared by silver nanoparticle deposition on porous silicon surface. They exhibit excellent characteristics in terms of sensitivity, reproducibility, stability, and uniformity. They could detect rhodamine 6G in femtomolar range with SERS enhancement factor of ~ 6.1 × 1012, which is best ever reported for these substrates. Molecule-specific sensing of water pollutants such as methylene blue, glyphosate, andchlorpyrifos, is demonstrated for concentrations well below their permissible limits along with excellent enhancement factors. Porous silicon substrate functionalized with Ag nanoparticles demonstrates to be a promising candidate for low-cost, long-life, reliable sensors for environmental conservation applications.

Colloidal carbon soot templated TiO2/Ag surface functionalized 3D printed metal brushes as new generation surface enhanced Raman scattering substrates

This present work demonstrated the functional transformation of 3D printed metal substrates into a new family of Surface-enhanced Raman Scattering substrates, a promising approach in developing SERS-based Point-of-care (PoC) analytical platforms. l-Powder Bed Fusion (l-PBF, Additive manufacturing or 3D printing technique) printed metal substrates have rough surfaces, and exhibit high thermal stability and intrinsic chemical inertness, necessitating a suitable surface functionalization approach. This present work demonstrated a unique multi-stage approach to transform l-PBF printed metal structures as recyclable SERS substrates by colloidal carbon templating, chemical vapor deposition, and electroless plating methods sequentially. The surface of the printed metal structures was functionalized using the colloidal carbon soot particles, that were formed by the eucalyptus oil flame deposition method. These carbon particles were shown to interact with the metals present in the printed structures by forming metal carbides and function as an adlayer on the surface. Subsequent deposition of TiO2 onto these templates led to strong grafting of TiO2 and retaining the fractal structure of the soot template onto the metal surface. Electroless deposition of silver nanoparticles resulted in the formation of fractally structured TiO2/Ag nanostructures and these functionalized printed metal structures were shown as excellent SERS substrates in enhancing the vibrational spectral features of Rhodamine B (RhB). The presence of TiO2 photocatalyst on the surface was shown to remove the RhB analyte from the surface under photochemical conditions, which enables the regeneration of SERS activity, and the substrate can be recycled. The migration of metals from the printed metal structures into the fractally ordered TiO2/Ag nanostructures was found to enhance the photocatalytic activity and increase the recyclability of these substrates. This study demonstrates the potential of 3D-printed Inconel metal substrates as next-generation recyclable SERS platforms, offering a substantial advancement over traditional colloidal, thin-film, flexible, and hard SERS substrates.

Functionalization of silver nanoparticles coating cotton fabrics through hydrothermal synthesis for improved antimicrobial properties

Deposition of silver nanoparticles (AgNPs) on the surfaces of cotton fabric (CF) is an approach for producing antimicrobial textile products. CF-AgNPs composites were fabricated ex situ using a simple hydrothermal synthesis of AgNPs, while the fabric was surface modified using a plasma to improve adhesion prior to coating. The morphology and chemical composition of CF-AgNPs nanocomposites were examined using UV–vis spectrophotometry (UV–vis), x-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Study results show uniform deposition of AgNPs on cotton fabrics. The CF-AgNPs composite material exhibits excellent laundering durability and antimicrobial performance against Gram-positive, Staphylococcus aureus and Gram-negative, Escherichia coli pathogens. These findings indicate that the developed fabric can be used in a wide range of biomedical applications, health care and various packaging systems.

Optimization of cotton SERS substrates based on different weave structures for surface trace detection

Cotton fabrics have been used to fabricate Surface-enhanced Raman spectroscopy (SERS) substrates due to their excellent properties such as flexibility, hygroscopicity, and large-scale production. The morphology of the SERS substrate has a great influence on the deposition of noble metal nanoparticles and affects the Raman-enhanced signal. Although numerous research reports have been conducted on SERS substrates made from cotton, there has been limited exploration on the impact of the weave structure of cotton fabric on SERS performance. Herein, the cotton SERS substrates were prepared by depositing silver nanoparticles (Ag NPs) on cotton fabrics with different weave structures by a simple vacuum-thermal evaporation method. The influence of substrate morphology on the deposition arrangement of Ag NPs and the enhancement of SERS performance was explored. The analysis findings demonstrate that the cotton SERS substrate displays exceptional Raman signal enhancement performance. Thereinto, the satin SERS substrate exhibited a stronger Raman signal due to its smoother surface favoring the deposition of Ag NPs. The limit of detection for p-aminothiophenol (PATP) was established at a low of 10−8 M, with an RSD value of 9.96%. Moreover, the satin SERS substrate demonstrated an enhancement factor of 5.18 × 105. In addition, it has excellent mechanical flexibility and good hygroscopicity, and thiram on the apple surface can be detected by simple wiping. Cotton SERS substrates show great potential in food safety analysis and monitoring. More importantly, this study provides assistance for the selection of SERS substrates for traditional cotton fabrics, and further promotes the broadening of the application fields of smart cotton fabrics.

Fabrication of Surface Enhanced Raman Spectroscopy based sensor using Ag NPs on copper tape flexible substrate

In this work, the authors have investigated the properties of thermally evaporated silver nanoarrays on copper tape (Ag/Cu) as flexible and reusable sensors for organic contaminants. Uniformly deposited silver nanoparticles (Ag NPs) with well-controlled sizes have formed by thermal evaporation. The deposition time is varied to obtain different morphology of the Ag nanoparticles. The Surface-enhanced Raman spectroscopy (SERS) efficiency has been optimized using Rhodamine 6G (R6G) as a test molecule. Morphological studies have also been carried out using scanning electron and atomic force microscopes. The Ag NPs on the copper tape-based sensor show a substantial enhancement in the order of 8.3x107 in the SERS signal for a deposition time of 10 s. Furthermore, we observe that as-prepared Ag/Cu tape can detect micro-molar alizarine red S (ARS), which exhibited excellent reproducibility as well. Hence, the flexible copper substrate proves to be a promising material for detecting environmental hazards at a meager cost.

Edge-site selective decoration of silver nanoparticles on TiO2 nanosheets for the rapid catalytic reduction of nitroarenes

In this study, we aim to construct an edge-site selective deposition of silver nanoparticles on TiO2 nanosheets (Ag-TiO2NSs) for the catalytic reduction of toxic nitroarenes (NAs) using NaBH4 medium. The as-prepared Ag-TiO2NSs were characterized by various analytical techniques such as XRD, HR-TEM, SEM-EDAX, elemental mapping and XPS analyses. The HR-TEM images confirmed that the Ag nanoparticles (AgNPs) size of around 3.05 ± 0.5 nm in diameter exhibited the selective growth specifically on the edges of the TiO2NSs. Additionally, it was observed that the TiO2NSs exhibited a high exposure of (101) facets. The prepared Ag-TiO2NSs catalyst exhibited remarkably high catalytic activity in the reduction of 4-nitrophenol (4-NP) (∼6 min, Kapp: 9.2 × 10−3 s−1 and TOF: 1.13 × 10−6 mol mg−1 min−1), which was comparable to or surpassing the catalytic performance of most of the previously reported Ag-based catalysts. Moreover, the catalyst showed an excellent catalytic reduction ability of other NAs such as 4-nitroaniline (4-NA) (∼10 min, 2.8 × 10−3 s−1), 4-(4-nitrophenyl)morpholine (4-NM) (∼8 min, 6.0 × 10−3 s−1), and 4-(2-fluoro-4-nitrophenyl)morpholine (4-FNM) (∼11 min, 4.2 × 10−3 s−1). In addition, the Ag-TiO2NSs exhibited commendable recyclability, with a minimal decrease in the activity over four consecutive recycling operations. The exceptional catalytic performance could be attributed to the smaller size of the AgNPs along with the synergistic effect between AgNPs and their interfacial contact with the (101) facet exposure of TiO2NSs. The Ag-TiO2NSs catalyst demonstrated the potential application for the catalytic reduction of 4-NP in a fixed bed reactor, operating under mild reaction conditions.

Braided silk sutures coated with photoreduced silver nanoparticles for eradicating Staphylococcus aureus and Streptococcus mutans infections

BackgroundInfections resulting from surgical procedures and wound closures continue to pose significant challenges in healthcare settings. To address this issue, the investigators have developed antibacterial non-resorbable braided silk sutures using in situ deposited silver nanoparticles (AgNPs) and investigated their efficacy in eradicating Staphylococcus aureus and Streptococcus mutans infections. MethodsThe braided silk sutures were modified through a simple and efficient in situ photoreduction method, resulting in the uniform distribution of AgNPs along the suture surface. The synthesized AgNPs were characterized using scanning electron microscopy (SEM), dynamic light scattering analysis (DLS) and Fourier Transform Infrared Spectroscopy analysis (FTIR) confirming their successful integration onto the silk sutures. The antibacterial activity of the nanoparticle coated sutures were compared and evaluated with non-coated braided silk sutures through in vitro assays against both S. aureus and S. mutans. ResultsThe surface and cross-sectional analysis of the treated sutures revealed a uniform and homogeneous distribution of silver particles achieved through the photoreduction of silver solution. This observation confirms the successful coating of silver nanoparticles (AgNPs) on the sutures. The antimicrobial studies conducted, demonstrated significant reductions in bacterial colonies when exposed to the silver nanoparticle-coated sutures. Notably, the width of the inhibition zone surrounding the coated sutures remained consistently wide and stable for duration up to 7 days. This sustained and robust inhibitory effect against gram-positive bacteria, specifically S. aureus and S. mutans, serves as strong evidence of the antibacterial efficacy of the coated sutures. ConclusionThe coating of silk sutures with AgNPs provided a significant and effective antibacterial capacity to the surgical sutures, with this activity being sustained for a period of 7 days. This suggests that AgNPs-in situ photoreduction deposited sutures have the potential to effectively manage S. aureus and S. mutans infections.

Fabrication of an Optoplasmonic Raft with Improved SERS Performance Detecting Methamphetamine through Bubble Enrichment.

In this work, a novel raft-like structure that combines noble metal nanoparticles (NPs) with an interconnected layer of hemispherical dielectric shell was fabricated and characterized. It was discovered that this hybrid material can enhance the optoplasmonic interaction between plasmonic and dielectric components, thereby improving the sensing performance in surface-enhanced Raman spectroscopy (SERS). Varied geometric parameters of the fabricated optoplasmonic raft, including the inner diameter and thickness of the dielectric shell, were attempted and analyzed through numerical simulation and experimental SERS measurements. With particular size, thickness, and incident orientation, the silica shell focuses the incident optical flow into the deposited silver NPs, undergoing similar near-field focusing behavior in comparison with other optoplasmonic entities. This optoplasmonic raft floating on the water surface is able to harvest the target molecules effectively through bubble enrichment, which rapidly captures and concentrates analytes from the aqueous phase. With a limited sampling time, the sensing performance of the developed optoplasmonic raft is improved by applying the optimized parameters involved in bubble enrichment. The substrates and corresponding enrichment method were implemented in the detection of methamphetamine (METH), achieving a limit of detection (LOD) down to 0.035 nM. As for practical onsite detection, the developed substrate and bubbling strategy were applied in an assembled set, employing a portable Raman spectrometer and an air pump. This set is able to detect METH dissolved in regular commercial beer, which is quite competent in the investigation of drug abuse.

Integration of a recyclable silver substrate for in situ surface-enhanced Raman spectroscopy in digital microfluidics.

We report a new chip-integrated recyclable SERS substrate, achieved by photochemical deposition of silver nanoparticles onto titanium dioxide (TiO2) thin film. Facilitated by the photocatalytic activity of titanium dioxide the SERS substrate can be recycled for multiple analysis. This enables quasi-real time detection of various compounds in an automated and reusable DMF-SERS platform.

Eco-friendly preparation and characterization of high-performance electrothermal graphene-AgNPs/lignocellulose composites.

Graphene-based (Gr-based) electrothermal heaters, due to their light weight, low electrical resistance, high thermal conductivity, and easy accessibility, have attracted widespread attention in the field of electrothermal heating. To achieve a high steady-state temperature in electrothermal heaters under low voltage, here we constructed a Gr-based film with low electrical resistance. Firstly, we employed non-toxic vitamin C to reduce silver nitrate for the in situ chemical deposition of silver nanoparticles (AgNPs) on the Gr surface. The SEM results confirmed that the AgNPs were uniformly deposited on the Gr surface. The synergistic interaction between AgNPs and Gr provided high-speed electrons transport paths for the film. On the other hand, we employed biodegradable lignocellulose fiber (LCF) as a dispersant and film-forming agent. The aromatic ring structure of LCF interacts with Gr via π-π interactions, aiding the dispersion of Gr in aqueous solutions. SEM results revealed that LCF permeated through the surfaces and interstices of the two-dimensional Gr sheets, providing mechanical support for the composite film. This approach enables the creation of freestanding Gr-AgNPs/LCF electrothermal composites. The resistivity and electrothermal results demonstrated that the obtained 20 wt% Gr-based composite film possessed low electrical resistance (5.4 Ω sq-1) and exhibited an outstanding saturated temperature of 214 °C under a very low input voltage of 7 V. The preparation method of this Gr-based composite film is simple, easy to operate, and environmentally friendly, providing a new reference for the preparation of eco-friendly and high-performance resistance heating electronics.

Fabrication of Ag-perovskite substrates for surface-enhanced Raman scattering via all-vacuum deposition

The first all-vacuum deposition for fabricating perovskite-based substrates for surface-enhanced Raman scattering (SERS) is reported. While thermal deposition of silver nanoparticles is commonly employed to generate Ag substrates for SERS...

Construction of durable antibacterial cellulose textiles through grafting dynamic disulfide-containing amino-compound and nanosilver deposition

Cotton textile is very comfortable to wear, and also provides an ideal environment for bacterial propagation, easily causing harm to human health. In order to address this issue, various antibacterial techniques are employed for cotton finishing. However, some processes are complex and involve the use of environmentally unfriendly chemicals. In this work, a durable and efficient antibacterial cotton fabric was prepared via grafting of an amino-compound containing dynamic disulfide bonds, and then in-situ deposition of silver nanoparticles (AgNPs). Briefly, the reactive α-lipoic acid-modified polyethyleneimine (mPEI) was introduced to the cotton fibers via thiol-ene click reaction. Subsequently, the amino groups and dynamically-generated sulfhydryl groups in the mPEI molecules were used to initiate the ultrafast reduction of silver ions without the participation of additional reductant, constructing a stable antibacterial layer on fiber surface. The results reveal that the amino and thiol groups of mPEI could form coordination bonds with the deposited silver nanoparticles, and the antibacterial ability of AgNP@cotton-g-mPEI fabric remains at a high level even after 20 washing cycles. After 30 min of contact with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the antibacterial rates against both bacteria reached 99.99 %. Meanwhile, the network matrix constructed by the recombination of the dynamic disulfide bonds in mPEI endows the cotton fabric with detectable wrinkle resistance and encouraging anti-ultraviolet effect. The present work provides a novel alternative for preparation of durable and efficient antibacterial textiles.

Flexible multiscale cavity with omnidirectionality and high stability for in-site SERS detection of nanoplastics on oyster

Nanoplastics are widespread and pose a potential threat to human health. In this work, we designed a flexible multiscale cavity structured (MCS) surface-enhanced Raman scattering (SERS) substrate decorating Ni3S2 nanocavity on a modified polyvinylidene fluoride (PVDF) microcavity. The dense two-dimensional Ni3S2 nanosheets can provide a large surface area for the deposition of plasmonic silver nanoparticles (Ag NPs), increasing the density and strength of the “hotspots”. Additionally, the nanocavity (width ∼500 nm), formed by the nanosheet surroundings, offers not only electromagnetic enhancement of the cavity mode for SERS but also a crucial detection site for nanoplastics attachment. This effectively addresses the challenge of SERS detection due to the scale mismatch between nanoplastics (>50 nm) and conventional “hotspots” (<10 nm). Moreover, the flexible imprinted PVDF microcavity endows the proposed substrate with omnidirectional “hotspots” enhancement, ensuring the signal stability and the feasibility of in-site detection of the actual sample. As a result, we achieved the successful in-site detection of polystyrene (PS) spheres of different sizes on the surface of oysters, with a detection limit of 10-3 mg/mL for 50 nm diameter. The flexible multiscale cavity SERS substrate is expected to show great potential in food safety and environmental monitoring.

One-step silver coating of polypropylene surgical mask with antibacterial and antiviral properties

Face masks can filter droplets containing viruses and bacteria minimizing the transmission and spread of respiratory pathogens but are also an indirect source of microbes transmission.A novel antibacterial and antiviral Ag-coated polypropylene surgical mask obtained through the in situ and one-step deposition of metallic silver nanoparticles, synthesized by silver mirror reaction combined with sonication or agitation methods, is proposed in this study.SEM analysis shows Ag nanoparticles fused together in a continuous and dense layer for the coating obtained by sonication, whereas individual Ag nanoparticles around 150 nm were obtained combining the silver mirror reaction with agitation. EDX, XRD and XPS confirm the presence of metallic Ag in both coatings and also oxidized Ag in samples by agitation. A higher amount of Ag nanoparticles is deposited on samples by sonication, as calculated by TGA. Further, both coatings are biocompatible and show antibacterial properties: coating by sonication caused 24 % and 40 % of bacterial reduction while coating by agitation 48 % and 96 % against S. aureus and E. coli, respectively. At 1 min of contact with SARS-CoV-2, the coating by agitation has an antiviral capacity of 75 % against 24 % of the one by sonication. At 1 h, both coatings achieve 100 % of viral inhibition. Nonetheless, larger samples could be produced only through the silver mirror reaction combined with agitation, preserving the integrity of the mask.In conclusion, the silver-coated mask produced by silver mirror reaction combined with agitation is scalable, has excellent physico-chemical characteristics as well as significant biological properties, with higher antimicrobial activities, providing additional protection and preventing the indirect transmission of pathogens.

Green synthesis of magnetic silver nanocomposite: the photocatalytic performance of nanocomposite to decolorize organic dyes

ABSTRACT The magnetite-silver nanocomposites (Fe3O4-Ag NCs) were synthesized via a facile and green process by Citrus sinensis peel extract. The deposition of silver nanoparticles (NPs) was confirmed by observing an absorption peak at the maximum wavelength at 422 nm in the suspension solution of samples, which is related to silver surface plasmon resonance (SPR). The characteristic diffraction patterns of Fe3O4 and Ag phases were characterized utilizing the XRD patterns and the average size of the crystals was 21 nm. The photocatalytic behavior of Fe3O4-Ag NCs was studied for the destruction of three organic dyes methyl green (MG), methyl orange (MO), and methylene blue (MB) below UV radiation. The effect of the amount of photocatalyst and volume of hydrogen peroxide as an oxidant in the process of dye degradation was also investigated. The complete degradation time of dyes MB, MG, and MO under UV irradiation in the presence of 0.002 g Fe3O4-Ag NCs were 57, 33, and 49 min, respectively. The time of degradation reactions showed the high photocatalytic performance of Fe3O4-Ag NCs. These results proved that the synergistic effect of magnetite in the role of supporting the silver NPs was a significant contribution to the excellent decolorization behavior of Fe3O4-Ag NCs.

Construction of SERS chip based on silver nanoparticles and detection of sports doping β-agonists

Sports doping is a persistent challenge in competitive sports, undermining the integrity of athletic competitions and posing health risks to athletes. This study focuses on the development of a surface-enhanced Raman spectroscopy (SERS) chip for the detection of β-agonists, such as clenbuterol, ractopamine, and salbutamol, which are commonly abused as performance-enhancing drugs. The SERS chip was constructed by depositing silver nanoparticles (AgNPs) onto activated carbon (AC) as a substrate, utilizing their plasmonic properties and ease of synthesis. The successful loading of AgNPs onto AC was confirmed by SEM imaging, demonstrating a uniform distribution of AgNPs on the surface of AC. The SERS chip exhibited enhanced sensitivity in detecting β-agonists compared to conventional methods. The SERS signals of the analytes decreased with decreasing concentrations, indicating the chip's ability to detect low-concentration analytes. Notably, the AC/AgNPs composite demonstrated stronger SERS signals compared to AgNPs alone, attributed to the improved loading efficiency and electromagnetic field enhancement provided by the AC substrate. The detection limit of the AC/AgNPs SERS chip for clenbuterol, ractopamine, and salbutamol was found to be 0.003 mg/L, 0.001 mg/L, and 0.007 mg/L, respectively. The developed SERS chip offers rapid and sensitive detection of β-agonists in sports doping control. It overcomes the limitations of conventional methods, such as immunoassays and chromatographic techniques, in terms of sensitivity, selectivity, and sample preparation time. The application of SERS in anti-doping efforts holds great promise for maintaining fair and clean sports competitions.

Stretchable textile with ultra-high electromagnetic interference shielding performance based on porous wrinkled conductive network

The soaring growth of flexible electronic devices has boosted the demand for electromagnetic interference (EMI) shielding materials with excellent stretchability, stability and even breathability. However, it is still a challenge to develop conductive materials with outstanding stretchable EMI shielding performance. In this work, we developed a textile with porous wrinkled conductive network through in situ polydopamine-assisted deposition of silver nanoparticles (AgNPs) on wrinkled fiber mat and polydimethylsiloxane post modification. This unique wrinkled conductive networks endows the textile with excellent electrical conductivity (103700 S/m), good breathability, superhydrophobicity, and ultra-high stretchable EMI shielding properties. The EMI shielding effectiveness (EMI SE) of the textile reaches 101.1 dB in unstretched state and still maintains at 94.1 dB at 100 % tensile strain. The superhigh EMI SE under such a high strain is much higher than the previously reported results so far. Moreover, the textile shows exceptionally good cyclic tensile durability under 100 % stain. After 1000 tensile cycles with 100 % strain, the EMI SE of sample only drops by 3.8 %. This work provides a new path for developing stretchable high EMI shielding performance materials, which is of great significance to solve the EMI problems of emerging flexible and wearable electronic devices.

In-situ deposition of silver nanoparticles on cuprous oxide hollow spheres for sensitive and recyclable SERS sensing in solution based on electromagnetic and chemical enhancement

In order to achieve widespread application of surface-enhanced Raman spectroscopy (SERS) technique for practical sensing illegal additives in food, it is crucial to construct a reliable SERS substrate that offers both high sensitivity and reusability. This work utilized a simple and rapid in-situ deposition method to deposit Ag nanoparticles onto hollow Cu2O nanospheres, resulting in the formation of Cu2O/Ag nanocomposites with photocatalytic and SERS properties. These nanocomposites were employed as a hopeful SERS analysis for effective sensing of colorant additives in fruit juice, including methylene blue (MB) and rhodamine 6G (R6G). Impressively, the nanocomposites exhibited an exceptional detection limit of 10−9 M for the color agents and demonstrated a strong linear relationship between SERS intensities and the logarithmic concentration (R2 ≥ 0.95). The hollow structure of Cu2O provided low density and long-term dispersion stability in solution, which are beneficial for real-time monitoring the additives in liquid food. The excellent SERS performance can be attributed to the electromagnetic effect of Ag metals and the chemical enhancement of Cu2O semiconductors, as confirmed by the N 1 s XPS spectra from MB. Furthermore, the Cu2O/Ag nanocomposites efficiently degraded dye molecules under UV light irradiation within a short period of 45 min. So, the nanocomposites exhibited practical recyclability, as demonstrated by their consistent performance over five cycles of SERS sensing. These findings highlight their significant potent for SERS sensing trace pollutants and ecological restoration by photocatalytic reaction in the future.

Role of Particle Shape, Substrate Streaming Potential, and Ionic Strength in Kinetics and Spatial Distribution of Electrostatically Deposited Silver Nanoparticles

Role of Particle Shape, Substrate Streaming Potential, and Ionic Strength in Kinetics and Spatial Distribution of Electrostatically Deposited Silver Nanoparticles