Quantitative phase study of the dynamic cellular response in femtosecond laser photoporation.
Ontology highlight
ABSTRACT:
SUBMITTER: Antkowiak M
PROVIDER: S-EPMC3018012 | biostudies-other | 2010
REPOSITORIES: biostudies-other
Similar Datasets
Project description:In this work, multiple filamentation competition of femtosecond pulse in methanol is studied both experimentally and numerically. The visualization of multiple filamentation competition has been realized in the experiment performing the three-photon fluorescence of Coumarin 440. The random changes of multiple filamentation stemmed from the jitter of the peak laser intensity ratio of initial hot spots are first observed directly and visually, which can be well explained by a simplified (2D+1)-dimensional model.
| S-EPMC5583335 | biostudies-literature
Project description:The formation of periodic surface structures is a general effect of femtosecond laser irradiation of solid targets showing promising interest in material science and technology. However, the experiments are typically carried out in air, a condition in which the target surface becomes densely decorated with nanoparticles that can influence the formation of the surface structures in the early stage of the irradiation process. Here we report an investigation of structures generation on a silicon surface irradiated in vacuum (10-5 mbar) with a low number of laser pulses (N???10) that exploits several microscopy techniques (optical, atomic force, electron and Raman). Our analyses allow identifying the creation of silicon phase-change gratings consisting of alternating amorphous and crystalline periodic lines, with almost no material removal, located at the periphery of a shallow ablation crater. These gratings originate from two different kinds of defects: (i) the first is characterized by a peculiar lobed shape that is produced by the first few laser pulses; (ii) the second is provided by the one-dimensional, linear singularity defined by the ablation edge of the nascent crater. Both kind of defects lead to grating structures extending outwards the amorphous central area of the crater along the direction of the laser polarization. Comparative analysis with the surface formed in air, in the same experimental conditions, evidences the important role played by nanoparticles densely decorating the target in air and the striking variation occurring in vacuum.
| S-EPMC6104067 | biostudies-literature
Project description:The photothermal kinetics of hollow gold nanorod (HGNR) under femtosecond laser irradiation are studied numerically with finite-element methods and a two-temperature model. Compared with solid gold nanorod (SGNR) with the same aspect ratio (AR), the localized surface plasmon resonance (LSPR) peak of HGNR can be red-shifted to the second near-infrared window, and the absorption cross-section of HGNR can be larger than that of SGNR. In addition, under the influence of an applied numerically electromagnetic field (simulated femtosecond laser irradiation), the heat generated by HGNR makes the temperature rise of the surrounding medium faster and higher. Compared with SGNR with the same resonance wavelength, HGNR has a slightly smaller absorption cross-section but can achieve a higher temperature rise of the external medium. In addition, the laser energy, required to achieve the critical temperature for selective photothermal damage of tumor cells, is also significantly reduced. Moreover, with the same incident laser energy, the decreasing of HGNR shell thickness leads to an increase of the temperature rise of the external medium, while the change of femtosecond laser pulse width will not significantly change the temperature rise of its lattice and the external medium. In short, this study aims to provide some useful insights for the applications of HGNR in photothermal tumor therapy.
| S-EPMC6566344 | biostudies-other
Project description:Natural musculoskeletal systems have been widely recognized as an advanced robotic model for designing robust yet flexible microbots. However, the development of artificial musculoskeletal systems at micro-nanoscale currently remains a big challenge, since it requires precise assembly of two or more materials of distinct properties into complex 3D micro/nanostructures. In this study, we report femtosecond laser programmed artificial musculoskeletal systems for prototyping 3D microbots, using relatively stiff SU-8 as the skeleton and pH-responsive protein (bovine serum albumin, BSA) as the smart muscle. To realize the programmable integration of the two materials into a 3D configuration, a successive on-chip two-photon polymerization (TPP) strategy that enables structuring two photosensitive materials sequentially within a predesigned configuration was proposed. As a proof-of-concept, we demonstrate a pH-responsive spider microbot and a 3D smart micro-gripper that enables controllable grabbing and releasing. Our strategy provides a universal protocol for directly printing 3D microbots composed of multiple materials.
| S-EPMC7484797 | biostudies-literature
Project description:Airway organoids derived from adult murine epithelial cells represent a complex 3D in vitro system mimicking the airway epithelial tissue’s native cell composition and physiological properties. In combination with a precise damage induction via femtosecond laser-based nanosurgery, this model allows for the examination of intra- and intercellular dynamics in the course of repair processes with a high spatio-temporal resolution, which can hardly be reached using in vivo approaches. For characterization of the organoids’ response to single or multiple-cell ablation, we first analyzed overall organoid survival and found that airway organoids were capable of efficiently repairing damage induced by femtosecond laser-based ablation of a single to ten cells within 24 h. An EdU staining assay further revealed a steady proliferative potential of airway organoid cells. Especially in the case of ablation of five cells, proliferation was enhanced within the first four hours upon damage induction, whereas ablation of ten cells was followed by a slight decrease in proliferation within this time frame. Analyzing individual trajectories of single cells within airway organoids, we found an increased migratory behavior in cells within close proximity to the ablation site following the ablation of ten, but not five cells. Bulk RNA sequencing and subsequent enrichment analysis revealed the differential expression of sets of genes involved in the regulation of epithelial repair, distinct signaling pathway activities such as Notch signaling, as well as cell migration after laser-based ablation. Together, our findings demonstrate that organoid repair upon ablation of ten cells involves the same key processes by which native airway epithelial wound healing is regulated. This marks the herein presented in vitro damage model suitable to study repair processes following acute airway injury, thereby posing a novel approach to gain insights into the mechanisms driving epithelial repair on a single-cell level.
2023-08-29 | GSE241237 | GEO
Project description:Numerous valuable studies on electron dynamics have focussed on the extraordinary properties of molybdenum disulfide (MoS2); however, most of them were confined to the level below the damage threshold. Here the electron dynamics of MoS2 under intense ultrafast laser irradiation was investigated by experiments and simulations. Two kinds of ablation mechanisms were revealed, which led to two distinct types of electron dynamics and final ablation morphology. At a higher fluence, the emergence of superheated liquid induced a dramatic change in the transient reflectivity and micro-honeycomb structures. At a lower fluence, the material was just removed by sublimation, and the ablation structure was relatively flat. X-ray photoelectron spectroscopic (XPS) measurements demonstrated that thermal decomposition only occurred at the higher fluence. Furthermore, a theoretical model was developed to deeply reveal the ultrafast dynamics of MoS2 ablation. The simulation results were in good agreement with the temporal and spatial reflectivity distribution obtained from the experiment. The electron and lattice temperature evolution was also obtained to prove the ablation mechanism. Our results revealed ultrafast dynamics of MoS2 above the damage threshold and are helpful for understanding the interaction mechanism between MoS2 and intense ultrafast lasers, as well as for MoS2 processing applications.
| S-EPMC7203173 | biostudies-literature
Project description:Ultrafast laser systems are becoming more widespread throughout the research and industrial communities yet eye protection for these high power, bright pulsed sources still require scrupulous characterization and testing before use. Femtosecond lasers, with pulses naturally possessing broad-bandwidth and high average power with variable repetition rate, can exhibit spectral side-bands and subtly changing center wavelengths, which may unknowingly affect eyewear safety protection. Pulse spectral characterization and power diagnostics are presented for a 80 MHz, Ti+3:Sapphire, ? 800 nm, ?40 femtosecond oscillator system. Power and spectral transmission for 22 test samples are measured to determine whether they fall within manufacturer specifications.
| S-EPMC5772908 | biostudies-literature
Project description:When a flying object becomes supersonic, a concomitant increase in drag leads to a considerable rise in fuel consumption. We show experimentally that an embarked terawatt femtosecond laser can significantly decrease this drag. We measured a 50% transient reduction of drag on a test model placed in a supersonic wind tunnel at Mach 3. This effect was initiated by the thin hot air column created in front of the supersonic object by filamentation of the laser pulse. We also show that this technique offers possibilities for steering.
| S-EPMC6214642 | biostudies-literature
Project description:Optical diffusers are widely used in filament lamps, imaging systems, display technologies, lasers, and Light Emitting Diodes (LEDs). Here, a method for the fabrication of optical diffusers through femtosecond laser machining is demonstrated. Float glass surfaces were ablated with femtosecond laser light to form nanoscale ripples with dimensions comparable to the wavelength of visible light. These structures produce highly efficient and wide field of view diffusers. The machined patterns altered the average surface roughness, with the majority of particles in the range of a few hundred nanometers. The optical diffusion characteristic and a maximum diffusion angle of near 172° was achieved with optimum machining parameters. The transmission performance of the diffusers was measured to be ∼30% across the visible spectrum. The demonstrated technique has potential for producing low-cost large area optical devices. The process benefits from the flexibility of the laser writing method and enables the production of custom optical diffusers.
| S-EPMC6112377 | biostudies-literature
Project description:Ultrahigh-resolution optical strain sensors provide powerful tools in various scientific and engineering fields, ranging from long-baseline interferometers to civil and aerospace industries. Here we demonstrate an ultrahigh-resolution fibre strain sensing method by directly detecting the time-of-flight (TOF) change of the optical pulse train generated from a free-running passively mode-locked laser (MLL) frequency comb. We achieved a local strain resolution of 18?p?/Hz1/2 and 1.9?p?/Hz1/2 at 1?Hz and 3?kHz, respectively, with large dynamic range of >154?dB at 3?kHz. For remote-point sensing at 1-km distance, 80?p?/Hz1/2 (at 1?Hz) and 2.2?p?/Hz1/2 (at 3?kHz) resolution is demonstrated. While attaining both ultrahigh resolution and large dynamic range, the demonstrated method can be readily extended for multiple-point sensing as well by taking advantage of the broad optical comb spectra. These advantages may allow various applications of this sensor in geophysical science, structural health monitoring, and underwater science.
| S-EPMC5645398 | biostudies-literature