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[IEEE 2018 International Symposium on Micro-NanoMechatronics and Human Science (MHS) - Nagoya, Japan (2018.12.9-2018.12.12)] 2018 International Symposium on Micro-NanoMechatronics and Human Science (MHS) - Uniform Transfection: Shock Wave Generation in Laser Ablation and Microcontact Printing
摘要： With the increasing need of regenerative medicines, cell therapy, and biopharmaceutical drug, it is necessary to develop a method for massively parallel delivery and uniform transfection. This research explores the possibility of using μCP (using cell adhesive and cell blocking agents) for printing massive number of cells on a substrate and using optoporation methods (nano-second pulsed radiation) to perforate cell membranes. With combining these two methods, a stand-alone micro-device capable of performing localized intracellular delivery will be developed. In this paper, we confirmed the generation of shock wave upon optoporation, tried intra-cellular delivery using Calcein, develop the stamp for micro-contact printing and performed the printing.
关键词： optoporation,laser ablation,uniform transfection,shock wave generation,microcontact printing
更新于2025-09-19 17:13:59
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Fabrication of silicon carbide nanoparticles using picosecond pulsed laser ablation in acetone with characterizations from TEM and XRD
摘要： We fabricated SiC nanoparticles (NPs) using a laser ablation method in acetone with a picosecond pulsed laser and characterized the resulting sizes, shapes, and crystal structures using transmission electron microscopy (TEM) and X-ray diffraction (XRD). We revealed two formation processes for the SiC NPs. The main process was the formation of spherical NPs with diameters primarily less than 10 nm. The crystal structure was 3C-SiC, which did not depend on a target polytype. Therefore, it is concluded that these NPs are grown from atomic molecules that disassociate from targets in the ablation process. As a result of a Rietbelt analysis of the XRD patterns, we clearly found that almost all NPs were single crystals. In addition, a stacking fault in the crystal was observed in the TEM image, which affects the XRD pattern. The other process was the formation of NPs with diameters from 30 to 80 nm with crystal structures that were the same as the targets. This indicates that these NPs were generated as fragments of the target. Our findings are useful for applications of SiC NPs to selectively control their size, shape, and crystal structure using laser ablation.
关键词： silicon carbide nanoparticles,3C-SiC,picosecond pulsed laser ablation,TEM,XRD
更新于2025-09-19 17:13:59
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Charged Particle Oscillations in Transient Plasmas Generated by Nanosecond Laser Ablation on Mg Target
摘要： The dynamics of a transient plasma generated by laser ablation on a Mg target was investigated by means of the Langmuir probe method and fractal analysis. The empirical data showcased the presence of an oscillatory behavior at short expansion times (<1 μs) characterized by two oscillation frequencies and a classical behavior for longer evolution times. Space- and time-resolved analysis was implemented in order to determine main plasma parameters like the electron temperature, plasma potential, or charged particle density. In the motion fractal paradigm, a theoretical model was built for the description of laser-produced plasma dynamics expressed through fractal-type equations. The calibration of such dynamics was performed through a fractal-type tunneling effect for physical systems with spontaneous symmetry breaking. This allows both the self-structuring of laser-produced plasma in two structures based on its separation on different oscillation modes and the determination of some characteristics involved in the self-structuring process. The mutual conditionings between the two structures are given as joint invariant functions on the action of two isomorph groups of SL(2R) type through the Stoler-type transformation, explicitly given through amplitude self-modulation.
关键词： laser ablation,joint invariant functions,Langmuir probe,fractal analysis,charged particle oscillations,Lie groups
更新于2025-09-19 17:13:59
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Direct and Rapid Multi-Element Analysis of Wine Samples in Their Natural Liquid State by Laser Ablation ICPMS
摘要： A simple and rapid method using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) for direct multi-element analysis of wine samples without any sample pretreatment is described. Bestowed to its micro-sample consumption, the proposed method offers advantages of direct multi-element analysis in wine samples with high ethanol (1%–20%) and salt contents, insignificant carbon deposits, reduced matrix effects, and better analytical performance. External calibration using either solid reference material NIST 610 glass or aqueous standard solutions in combination with indium internal standard provides accurate results. This calibration strategy offers a solution to the lack of a multi-element certified wine reference material for matrix-matched calibration. Twenty elements (Li, B, Mg, Al, V, Mn, Co, Cu, Zn, Rb, Sr, Y, Cs, Ba, La, Ce, Pr, Nd, Pb, and U) were determined in wine samples. The proposed method was validated by a comparison to the conventional solution nebulization ICPMS method, with satisfying results. The detection limits for these elements were 0.01–1 ng mL-1. The proposed method has a great potential for multi-element analysis in other beverages.
关键词： Direct analysis,ICPMS,Multi-element analysis,Laser ablation,Wine
更新于2025-09-19 17:13:59
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Synthesis and Deposition of Ag Nanoparticles by Combining Laser Ablation and Electrophoretic Deposition Techniques
摘要： Silver nanostructured thin films have been fabricated on silicon substrate by combining simultaneously pulsed laser ablation in liquid (PLAL) and electrophoretic deposition (ED) techniques. The composition, topography, crystalline structure, surface topography, and optical properties of the obtained films have been studied by energy dispersive X-ray spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and UV-visible spectrophotometry. The coatings were composed of Ag nanoparticles ranging from a few to hundred nm. The films exhibited homogenous morphology, uniform appearance, and a clear localized surface plasmon resonance (LSPR) around 400 nm.
关键词： pulsed laser ablation in liquid,electrophoretic deposition,silver nanoparticles
更新于2025-09-19 17:13:59
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Femtosecond Laser Ablation for Mesoscale Specimen Evaluation
摘要： Focused ion beam machining revolutionized the way samples are studied in materials science. The introduction of this tool enabled researchers to break into new frontiers of research. While this method focused on the nanometer length scale, the mesoscale manufacturing of samples has not seen such advances. It remains a challenge to manufacture sample geometries too large for focused ion beam milling yet too small for conventional machining. Femtosecond laser ablation opens this length scale of sample space and allows the fabrication of numerous useful geometries. This paper outlines a state-of-the-art femtosecond laser machining system that can be used for rapid, micro- and mesoscale sample preparation. To illustrate the utility of this system, stress–strain data are presented for single-crystal Cu micropillars and three microscale tensile test specimens prepared from physical-vapor-deposited Cu and Ni foils.
关键词： Femtosecond laser ablation,mesoscale specimen,microstructure examination,mechanical testing
更新于2025-09-19 17:13:59
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Engineering the crystalline silicon surface by femtosecond laser processing in liquid: hierarchical micro/nanostructure and amorphization
摘要： Hierarchical micro/nanostructure surface structures with different spatial characteristics are achieved after irradiation of crystalline silicon via femtosecond (fs) laser pulses (800 nm, 120 fs, 1 kHz) with the sample submerged in ethanol. According to laser pulse energy and fabrication parameters (such as scanning speed and superimposing writing), a characteristic morphology evolution of ovoid-like smooth modified area, ripple-like, wave-like, and coral-like micro/nanostructures is demonstrated, and the underline principle is discussed. The amorphization of fs laser-modified area is verified and investigated by Raman spectroscope. These modified structures have potential applications in sensors, silicon photovoltaic cells, and sterilization.
关键词： topographical surface alterations,black silicon,laser ablation in liquid,femtosecond phenomena
更新于2025-09-19 17:13:59
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Transition Metal Carbide Core/Shell Nanoparticles by Ultra-Short Laser Ablation in Liquid
摘要： Transition metal carbide nanoparticles are a class of technological interesting materials with a wide range of applications. Among metal carbides, tantalum carbides have good compatibility with the biological environment while molybdenum carbides are used as catalyst in electrochemical reactions. Laser ablation of bulk transition metal targets in some liquids is here reported and laser ablation in organic solvents is used as simple synthetic strategy for the production of carbide nanostructures. Herein, the nanoparticles produced by ultra-short laser ablation of tantalum and molybdenum in water, acetone, ethanol and toluene have been characterized by TEM, XRD and XPS analysis. The combined effect of metal and solvent chemical and physical properties on the composition of the nanomaterials obtained has been pointed out. In particular, the different reactivity of Ta and Mo with respect to oxidizing species determines the composition of particles obtained in water, on the other hand the organic solvents decomposition allows to obtain transition metal carbide (TMC) nanoparticles. The observed carbonaceous shell formed on TMC allows to protect the particle’s carbidic core and to improve and tailor the applications of these nanomaterials.
关键词： ultrashort laser ablation in liquid,transition metal carbide,core/shell nanostructures,solvent degradation
更新于2025-09-19 17:13:59
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Synthesis of ZnO and Au@ZnO core/shell nano-catalysts by pulsed laser ablation in different liquid media
摘要： We report the synthesis of colloidal solution of ZnO and Au@ZnO core/shell nanoparticles by one-pot nanosecond laser ablation (1st harmonic of Nd:YAG laser) method in different liquid media (Ultrapure water and Chloroauric acid). The structural, morphological and optical properties had been studied. X-ray diffraction analysis showed their hexagonal wurtzite structure while UV–vis analysis investigated the quantum confinement and surface plasmon resonance of the prepared nanostructured particles with significant changes in color behavior. Transmission electron microscopic analysis revealed the homogeneous spherical shape with an average particle size about 39 nm and 50 nm for Au@ZnO core/shell and ZnO, respectively. Also, it is confirmed that the produced nanostructured material in the case of chloroauric acid is core/shell structure where Au is the core while ZnO is the shell. In contrast to ZnO, Au@ZnO displayed more significant Chemical-catalytic degradation activity toward the degradation of 4-nitrophenol to 4-aminophenol in only 4 min rather than ZnO that required 12 min for the same degree of conversion.
关键词： ZnO,Laser ablation,Nanoparticles,4-nitrophenol,Core/shell
更新于2025-09-19 17:13:59
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Hierarchical Laser-Patterned Silver/Graphene Oxide Hybrid SERS Sensor for Explosive Detection
摘要： We demonstrate an ultrafast laser-ablated hierarchically patterned silver nanoparticle/graphene oxide (AgNP/GO) hybrid surface-enhanced Raman scattering (SERS) substrate for highly sensitive and reproducible detection of an explosive marker 2,4-dinitrotoluene (2,4-DNT). A hierarchical laser-patterned silver sheet (Ag?S) is achieved by ultrafast laser ablation in air with pulse energies of 25, 50, and 100 μJ. Multiple laser pulses at a wavelength of 800 nm and a pulse repetition rate of 50 fs at 1 kHz are directly focused on Ag?S to produce and deposit AgNPs onto Ag?S. The surface morphology of ablated Ag?S was evaluated using atomic force microscopy, optical pro?lometry, and ?eld emission scanning electron microscopy (FESEM). A rapid increase in the ablation rate with increasing laser energy was observed. Selected area Raman mapping is performed to understand the intensity and size distribution of AgNPs on Ag?S. Further, GO was spin-coated onto the AgNPs produced by ultrafast ablation on Ag?S. The hierarchical laser-patterned AgNP/GO hybrid structure was characterized using FESEM, high-resolution transmission electron microscopy, X-ray di?raction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Further, hierarchical laser-patterned AgNP/GO hybrid structures have been utilized as SERS-active substrates for the selective detection of 2,4-DNT, an explosive marker. The developed SERS-active sensor shows good stability and high sensitivity up to picomolar (pM) concentration range with a Raman intensity enhancement of ～1010 for 2,4-DNT. The realized enhancement of SERS intensity is due to the cumulative e?ect of GO coated on Ag?S as a proactive layer and AgNPs produced by ultrafast ablation.
关键词： silver nanoparticle/graphene oxide (AgNP/GO) hybrid,ultrafast laser ablation,explosive detection,surface-enhanced Raman scattering (SERS),2,4-dinitrotoluene (2,4-DNT)
更新于2025-09-19 17:13:59