Laser Ablation In Liquid Research Articles

Enhanced Characteristics of Iron Oxide Nanoparticles for Efficient Pollutant Degradation via Pulsed Laser Ablation in Liquid

Enhanced Characteristics of Iron Oxide Nanoparticles for Efficient Pollutant Degradation via Pulsed Laser Ablation in Liquid

Development of silver nanocubes created by pulsed laser ablation in liquid

This paper describes a simple approach for creating silver (Ag) nanocubes using pulsed laser ablation in a liquid medium. The development of nanocubical formations of Ag obtained by laser ablation using Nd: YAG laser was conducted for 5, 10, 15, and 20[Formula: see text]min. The surface morphological analysis was performed using field-emission scanning electron microscopy (FESEM) to show the formation of silver nanocubes with edge lengths ranging from 150[Formula: see text]nm to 250[Formula: see text]nm. The UV-visible spectroscopy demonstrates that the concentration of Ag nanostructures, evidenced by the characteristic localized surface plasmon resonance band near 400[Formula: see text]nm in the colloidal solution containing Ag nanoparticles, increased with the increasing laser ablation duration from 5[Formula: see text]min to 20[Formula: see text]min. The growth mechanism for Ag nanocubes can be easily understood with the change in laser ablation time from 5 to 10, 15, and then 20[Formula: see text]min. The Ag sheets with no specific shape start to develop after 5 min of laser ablation, and after 10[Formula: see text]min, larger particles form. Then, after 15[Formula: see text]min, a small number of cube-like nanostructures with rough and uneven edges was obtained. At the end of 20[Formula: see text]min, a complete cubic formed with fine and distinct edges and a very large amount of nanocubes. The elemental silver signal was present in Ag nanocubes, as revealed by the energy-dispersive X-ray spectroscopy (EDS) spectra. The produced Ag nanocubes may be used to construct two-dimensional nanocomposites with practical applications in the electrical, optoelectronic, electrochemical, and biological areas.

Laser-optimized Pt-Y alloy nanoparticles embedded in Pt-Y oxide matrix for high stability and ORR electrocatalytic activity

The development of active yet stable catalysts for oxygen reduction reaction (ORR) is still a major issue for the extensive permeation of fuel cells into everyday technology. While nanostructured Pt catalysts are to date the best available systems in terms of activity, the same is not true for stability, particularly under operating conditions. In this work, PtXY alloy nanoparticles are proposed as active and durable electrocatalysts for ORR. PtXY nanoalloys are synthesized and further optimized by laser ablation in liquid followed by laser fragmentation in liquid. The novel integrated laser-assisted methodology succeeded in producing PtxY nanoparticles with the ideal size (<10 nm) of commercial Pt catalysts, yet resulting remarkably more active with E1/2 = 0.943 V vs. RHE, specific activity = 1095 μA cm−2 and mass activity > 1000 Ag−1. At the same time, the nanoalloys are embedded in a fine Pt oxide matrix, which allows a greater stability of the catalyst than the commercial Pt reference, as directly verified on a gas diffusion electrode.

Prospects for Ultrafast Observation of Femtosecond Laser Ablation in Liquid(Invited)

Prospects for Ultrafast Observation of Femtosecond Laser Ablation in Liquid(Invited)

Uncovering gold nanoparticle synthesis using a microchip laser system through pulsed laser ablation in aqueous solution

A compact, low-power microchip laser system is utilized for pulse laser ablation in liquids, and the impact of solution viscosity on the efficiency of gold nanoparticle ablation in PVP solutions is explored.

Assessment of laser-synthesized Si nanoparticle effects on myoblast motility, proliferation and differentiation: towards potential tissue engineering applications.

Due to their biocompatibility and biodegradability and their unique structural and physicochemical properties, laser-synthesized silicon nanoparticles (Si-NPs) are one of the nanomaterials which have been most studied as potential theragnostic tools for non-invasive therapeutic modalities. However, their ability to modulate cell behavior and to promote proliferation and differentiation is still very little investigated or unknown. In this work, ultrapure ligand free Si-NPs of 50 ± 11.5 nm were prepared by femtosecond (fs) laser ablation in liquid. After showing the ability of Si-NPs to be internalized by murine C2C12 myoblasts, the cytotoxicity of the Si-NPs on these cells was evaluated at concentrations ranging from 14 to 224 μg mL-1. Based on these findings, three concentrations of 14, 28 and 56 μg mL-1 were thus considered to study the effect on myoblast differentiation, proliferation and motility at the molecular and phenotypical levels. It was demonstrated that up to 28 μg mL-1, the Si-NPs are able to promote the proliferation of myoblasts and their subsequent differentiation. Scratch tests were also performed revealing the positive Si-NP effect on cellular motility at 14 and 28 μg mL-1. Finally, gene expression analysis confirmed the ability of Si-NPs to promote proliferation, differentiation and motility of myoblasts even at very low concentration. This work opens up novel exciting prospects for Si-NPs made by the laser process as innovative tools for skeletal muscle tissue engineering in view of developing novel therapeutic protocols for regenerative medicine.

Preparation ZnO nanoparticles with Different Concentration by Laser Ablation in Liquid and their use in anti bacterial activity

Preparation ZnO nanoparticles with Different Concentration by Laser Ablation in Liquid and their use in anti bacterial activity

Structure and Composition of High-Entropy-Alloy Nanoparticle synthesized by Pulsed Laser Ablation in Liquid

Structure and Composition of High-Entropy-Alloy Nanoparticle synthesized by Pulsed Laser Ablation in Liquid

Synthesis and characterization of MoSe2 nanoscrolls via pulsed laser ablation in deep eutectic solvents.

There is ongoing interest in the rapid, reproducible production of 2-dimensional (2-D) transition metal dichalcogenides (TMD), such as molybdenum-based TMD (MoX2), where X is a chalcogen atom such as sulphur (S), selenium (Se) or tellurium (Te), driven by their unique optical and electronic properties. Once fabricated into an atomically thin layer structure, these materials have a direct-indirect bandgap transition, strong spin-orbit coupling, and favourable electronic and mechanical strain-dependent properties which are attractive for electronics. Pulsed laser ablation in liquid (PLAL) is an economic, green alternative for synthesis of TMD. It has been shown that in the case of MoX2, the chemical processes during the plasma phase of the ablation can yield the formation of multispecies, including MoOx quantum dots when oxygen-containing solvents are used. Here, we introduce the formation of MoSe2 nanoscrolls with low oxygen content synthesized via pulsed laser ablation in deep eutectic solvents (PLADES). Our results suggest that the synthesis produces a stable colloidal solution of large 2-D structures with tuneable surface charge by replacing the deep eutectic solvent (DES) with DI water. Nuclear Magnetic Resonance (NMR) results suggest that irradiating the solvent at near infrared NIR energy does not affect its chemical composition. NMR also proves that serial washing can completely remove solvent from the nanostructures. Raman shifts suggest the formation of large, thin MoSe2 nanosheets aided by the solvent confinement resulting from van der Waal forces and hydrogen bonds interactions between MoSe2 and urea. Binding energies measured by X-ray photoelectron spectroscopy (XPS) confirm MoSe2-DES preference to form 1T-MoSe2versus molybdenum oxides and 2H MoSe2 in DI-water. Raman and XPS findings were validated by transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Results of this work validate the use of PLADES for the synthesis of stable, crystalline, low-surface-oxygen-content colloidal MoSe2 nanoscrolls in scalable quantities.

External electric field assisted laser-induced plasma and bubble dynamics for optimizing Mn2O3 nanoparticles as UV emitters.

To gain a deeper understanding of how the size of the nanoparticles synthesized by Electric Field-Assisted Laser Ablation in Liquids (EFLAL) changes with the applied electric field, we use Laser-Induced...

Effect of Silver Nanoparticles Synthesized by Pulsed Laser Ablation in Liquid on the Hematological, Hepatic, and Renal Functions of Albino Rats

Silver nanoparticles (Ag-NPs) have unique properties as antibacterial effects against locally isolated clinical Escherichia coli. In this study, the evaluated the antibacterial activity of AgNPs, which were synthesized by laser ablation, against locally isolated clinical Escherichia coli on nutrient agar media in vitro. Then assessed the toxicity of the bactericidal dose in albino rats in vivo with hematological, liver, and kidney functions as vital parameters. AgNPs were synthesized by pulsed laser ablation in liquid (PLAL). AgNPs’ shape and nano size were characterized by atomic force microscopy (AFM), UV-vis spectroscopy, and scanning electron microscopy (SEM). UV peak absorption was observed at 434 nm, which produced an average particle diameter of 28.09 nm. The SEM and AFM topography images of the synthesized nanoparticles showed that they had a spherical shape. Also studied was the toxicity of the synthesized AgNPs in vivo. Four groups of albino rats were used. The liver and kidneys were found to be the main organs that accumulate AgNP. In this study, we examined the influence of intraperitoneally injected AgNPs on blood parameters (complete blood picture) and liver and kidney functions of albino rats. Blood ALP and serum test (GOT and GPT), serum urea and serum creatinine were analyzed at 15, 30, and 60 days after injection of 200 mg/kg of PLAL-synthesized AgNP. The results did not indicate statistically significant differences between the control and treatment groups in blood picture and enzyme levels tested that indicate proper liver function. Additionally, no differences in kidney functions were found during varying time intervals in the blood of rats. Thus, PLAL-synthesized AgNPs could inhibit Escherichia coli bacterial growth.

Effect of Electrode Potential on the Surface Chemical Composition of Au-Pd Nanoparticles

Palladium (Pd) nanoparticles have been investigated for the hydrogen evolution reaction, the hydrogen oxidation reaction, the oxygen reduction reaction, and the methanol and ethanol oxidation reaction. The high methanol/ethanol tolerance of Pd is noteworthy.A powerful approach to further improving the catalytic properties of Pd is through alloying with suitable co-metals. In the case of the ethanol oxidation reaction in alkaline media, Pd alloyed with Au has demonstrated excellent activity exceeding even that of highly active Pt catalysts (1). A complete miscibility, small lattice mismatch, and contrasting properties of Pd and Au make Au-Pd a unique model system. Marked changes in the reactivity of Au-Pd catalysts have been reported when conditioning and operating conditions are altered, which should be related to physico-chemical changes in the nanoparticles. Indeed, dealloying/dissolution and segregation of metals at the surface of nanoparticles (NPs) takes place during conditioning and operation, which have pronounced effect on the activity and stability of NPs. The migration of metals from the bulk to the nanoparticles’ surface may take place during pre-catalytic conditioning and during operation, and can be triggered by the presence of oxidation and reducing agents (2), changes in temperature, and potential cycling (3). Thus, it is critical to investigate the effect of electrode potential on metals dissolution and segregation occurring in alloyed nanoparticles.In the present work, Au-Pd NPs prepared by pulsed laser ablation in liquids were used. Pulsed laser ablation is a simple method to synthesize alloy NPs with high purity out of different material systems and with different compositions. Typically, alloy-metal targets or pressed micro-powder mixture targets are ablated or fragmentated in liquid, respectively. Notably, the technique does not require any surfactant additives to achieve NPs stability in the electrolyte, thus allowing for NPs to remain free of associated contamination from the capping agents. We will show how one can fine-tuned the Au and Pd surface fraction of bimetallic Au-Pd nanoparticles using electrochemistry. The method involves electrochemical cycling in alkaline medium at a suitable upper vertex potential, resulting in a controllable diffusion of Pd atoms from the core to the shell. This preferential outward diffusion of Pd atoms occurs because of the electrochemical adsorption of oxygen atoms at the surface of NPs, which is driven by the application of a potential. This potential has to be positive enough for oxygen atoms to adsorb at the surface of the NPs, and therefore is dependent on the nature of the surface atoms. On AuPd NPs that are enriched with Au atoms, a potential of +1.5 V vs. RHE must be applied to form ca. 1 ML of adsorbed oxygen at the surface of gold and initiate the diffusion of Pd atoms from the core to the NP surface. This approach marks a new avenue in the development of compositionally-controlled electrocatalysts and can be tailored to suit different applications with a simple switch of voltage or a controlled pretreatment.

Towards enhancing ODS composites in laser powder bed fusion: Investigating the incorporation of laser-generated zirconia nanoparticles in a model iron–chromium alloy

Oxide dispersion-strengthened (ODS) steel is a sought-after composite material known for its high demand in high-temperature and corrosive environments. Achieving the desired ODS steel properties requires specific conditions for the size and nanoparticles (NP) distribution in the printed part. Laser ablation in liquid (LAL) enables precise NP size adjustment. At the same time, the dynamic melt pool solidification in the Laser Powder Bed Fusion (PBF-LB/M) process complements this by creating favorable conditions for successful ODS processing. In this study, ZrO2 NP with a small and narrow particle size distribution (d50 = 3.8 nm; d90 = 10 nm) is produced by LAL. Dielectrophoretic deposition achieves the homogeneous, deformation-free coating of the binary Fe20Cr (wt.-%) matrix powder with NP. PBF-LB/M printed parts out of the oxide-additivated powder exhibit a crack-free structure and a density of up to 98%. Expectedly, the metal matrix grain sizes and room temperature microhardness (~ 220 HV) are not affected by NP addition. NP tracing by 2D simulation indicates a homogeneous NP distribution and less than 10% NP to be agglomerated in the solidified part. Thus, a promising perspective for a complete laser-based process chain for generating and processing ODS alloys is outlined.Graphical abstractTable of Contents

How Nanoparticle Size and Bubble Merging Is Governed by Short‐Range Spatially Controlled Double‐Beam Laser Ablation in Liquids

AbstractPulsed laser ablation in liquid (LAL) is a method for synthesizing nanoparticles with controlled composition and high purity. However, current research predominantly examines isolated cavitation bubbles, overlooking real‐world LAL scenarios where numerous bubbles interact simultaneously. This study addresses this gap by investigating the effects of short‐range micrometric spatially controlled double‐pulse laser ablation in liquids on nanoparticle size distribution. Gold and YAG are used as model materials, and a dimensionless parameter, H*, is introduced to quantify the ratio between double bubble spatial separation and their maximum height. This parameter correlates with cavitation bubble merging time, bubble volume change rate, and subsequent nanoparticle size increase. Shadowgraphs provide valuable insights into bubble contact and fusion dynamics, showcasing phase separation by a thin water film and subsequent merging into a single bubble. Notably, a twofold increase in nanoparticle size is observed for both Au and YAG at H* = 0.25. The research indicates a strong association between nanoparticle size trends and cavitation bubble volume rate change, particularly emphasized at H* = 0.25. Understanding the dynamics of neighboring bubbles during LAL emphasizes the relevance of lateral pulse distances in dual‐beam LAL, impacting particle size distribution in a distance‐dependent manner.

Enhancement of Metal Nanostructure Deposition on Silicon Laser-Induced Periodic Surface Structures by Galvanic Replacement.

We report a chemically motivated, single-step method to enhance metal deposition onto silicon laser-induced periodic surface structures (LIPSSs) using reactive laser ablation in liquid (RLAL). Galvanic replacement (GR) reactions were used in conjunction with RLAL (GR-RLAL) to promote the deposition of Au and Cu nanostructures onto a Si LIPSS. To increase the deposition of Au, sacrificial metals Cu, Fe, and Zn were used; Fe and Zn also enhanced the deposition of Cu. We show that the deposited metal content, surface morphology, and metal crystallite size can be tuned based on the difference in electrochemical potentials of the deposited and sacrificial metal. Compared to the Au and Cu reference samples, GR more than doubled the metal content on the LIPSS and reduced metal crystallite sizes by up to 20%. The ability to tune the metal content and crystalline domain size simultaneously makes GR-RLAL a potentially useful approach in the manufacturing of functional metal-LIPSS materials such as surface-enhanced Raman spectroscopy substrates.

Bacteria‐Epithelial Cell Interaction Influences Cytotoxicity and Antibacterial Effect of Silver‐Gold Alloy Nanoparticles on a Species‐Specific Level

AbstractThe rising number of antibiotic‐resistant bacteria requires alternative antibacterial substances as therapeutics. However, besides a strong effect against bacteria, they should not exhibit cytotoxicity towards human cells. Typically, both properties are tested in separate in vitro experiments that do not take into account naturally occurring interactions. To analyze whether the bacteria‐cell interaction influences the results of antibacterial and cytotoxic testing, surfactant‐free antibacterial silver‐gold alloy nanoparticles produced by laser ablation in liquid were examined both separately and in a straightforward coculture setup. Whereas different commensal bacteria and human skin cells exhibited reduced metabolic activity at comparable concentrations when treated separately, their response completely differed when analyzed in a combined coculture. For the combination of oral keratinocytes and Staphylococcus aureus, reduced cytotoxicity with increasing cell numbers, but a similar antibacterial effect quantified by standard plate counting could be observed. In contrast, coculture of keratinocytes and Porphyromonas gingivalis resulted in a complete absence of cytotoxicity and antibacterial effect, probably due to bacterial invasion of cells. These results clearly showed that the bacteria‐cell interaction greatly influences the results of antibacterial and cytotoxic testing and highlight the importance of more complex in vitro experiments to reliably characterize novel antibacterial substances for efficient clinical translation.

Multiwavelength SERS of Magneto-Plasmonic Nanoparticles Obtained by Combined Laser Ablation and Solvothermal Methods.

The present study introduces a novel method for the synthesis of magneto-plasmonic nanoparticles (MPNPs) with enhanced functionality for surface-enhanced Raman scattering (SERS) applications. By employing pulsed laser ablation in liquid (PLAL) to synthesize plasmonic nanoparticles and wet chemistry to synthesize magnetic nanoparticles, we successfully fabricated chemically pure hybrid Fe3O4@Au and Fe3O4@Ag nanoparticles. We demonstrated a straightforward approach of an electrostatic attachment of the plasmonic and magnetic parts using positively charged polyethylenimine. The MPNPs displayed high SERS sensitivity and reproducibility, and the magnetic part allowed for the controlled separation of the nanoparticles from the reaction mixture, their subsequent concentration, and their precise deposition onto a specified surface area. Additionally, we fabricated alloy based MPNPs from AgxAu100-x (x = 50 and 80 wt %) targets with distinct localized surface plasmon resonance (LSPR) wavelengths. The compositions, morphologies, and optical properties of the nanoparticles were characterized by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-vis spectroscopy, and multiwavelength Raman spectroscopy. A standard SERS marker, 4-mercaptobenzoic acid (4-MBA), validated the enhancement properties of the MPNPs and found an enhancement factor of 2 × 108 for the Fe3O4@Ag nanoparticles at 633 nm excitation. Lastly, we applied MPNP-enhanced Raman spectroscopy for the analysis of the biologically relevant molecule adenine and found a limit of detection of 10-7 M at 785 nm excitation. The integration of PLAL and wet chemical methods enabled the relatively fast and cost-effective production of MPNPs characterized by high SERS sensitivity and signal reproducibility that are required in various fields, including biomedicine, food safety, materials science, security, and defense.

Laser trapping of cavitation bubbles in liquids

Cavitation has a significant impact on pulsed laser ablation of liquids. At high repetition rates of laser pulses, it tends to hinder laser breakdown and associated processes. Here, we report on the particular case of the cavitation process occurring only at the elevated pulse repetition rate — the formation of a laser trapped bubble. The effect was observed in liquid hydrocarbons (n-hexane and ethanol) and water. The cavitation bubbles generated by picosecond pulses were captured in the caustic beam in front of the laser focus and stay there for a long time (several seconds). After growing up to ∼100μm in size, such a bubble completely blocks the laser radiation and stops all processes in the laser waist. The scenario of laser trapped bubble formation is investigated, the effects of pulse energy and pulse repetition rate are analyzed, and a possible mechanism for the observed effect is proposed. The special importance of laser trapped bubbles for the optimization of laser synthesis of new materials, particularly the linear carbon chains in hydrocarbons, is demonstrated.

Monte Carlo Approach to the Evaluation of Nanoparticles Size Distribution from the Analysis of UV-Vis-NIR Spectra.

How nice would it be to obtain the size distribution of a nanoparticle dispersion fast and without electron microscope measurements? UV-Vis-NIR spectrophotometry offers a very rapid solution; however, the spectra interpretation can be very challenging and needs to take into account the size distribution of the nanoparticles and agglomeration. This work suggests a Monte Carlo method for rapid fitting UV-Vis-NIR spectra using one or two size distributions starting from a dataset of precomputed spectra based on Mie theory. The proposed algorithm is tested on copper nanoparticles produced with Pulsed Laser Ablation in Liquid and on gold nanoparticles from the literature. The fitted distribution results are comparable with Transmission Electron Microscope results and, in some cases, reflect the presence of agglomeration.

Laser-Synthesized Elemental Boron Nanoparticles for Efficient Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) is one of the most appealing radiotherapy modalities, whose localization can be further improved by the employment of boron-containing nanoformulations, but the fabrication of biologically friendly, water-dispersible nanoparticles (NPs) with high boron content and favorable physicochemical characteristics still presents a great challenge. Here, we explore the use of elemental boron (B) NPs (BNPs) fabricated using the methods of pulsed laser ablation in liquids as sensitizers of BNCT. Depending on the conditions of laser-ablative synthesis, the used NPs were amorphous (a-BNPs) or partially crystallized (pc-BNPs) with a mean size of 20 nm or 50 nm, respectively. Both types of BNPs were functionalized with polyethylene glycol polymer to improve colloidal stability and biocompatibility. The NPs did not initiate any toxicity effects up to concentrations of 500 µg/mL, based on the results of MTT and clonogenic assay tests. The cells with BNPs incubated at a 10B concentration of 40 µg/mL were then irradiated with a thermal neutron beam for 30 min. We found that the presence of BNPs led to a radical enhancement in cancer cell death, namely a drop in colony forming capacity of SW-620 cells down to 12.6% and 1.6% for a-BNPs and pc-BNPs, respectively, while the relevant colony-forming capacity for U87 cells dropped down to 17%. The effect of cell irradiation by neutron beam uniquely was negligible under these conditions. Finally, to estimate the dose and regimes of irradiation for future BNCT in vivo tests, we studied the biodistribution of boron under intratumoral administration of BNPs in immunodeficient SCID mice and recorded excellent retention of boron in tumors. The obtained data unambiguously evidenced the effect of a neutron therapy enhancement, which can be attributed to efficient BNP-mediated generation of α-particles.