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Localized fluorescence emission in the dye (GFP) spectral range has been collected by a fluorescence microscopy setup. (a−d) Efficiency of the method to perfectly address the final collapsing site and reconstruct a desired pattern point-by-point.
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The possibility of investigating small amounts of molecules, moieties or nano-objects dispersed in solution constitutes a central step for various application areas in which high sensitivity is necessary. Here, we show that the rapid expansion of a water bubble can act as a fast-moving net for molecules or nano-objects, collecting the floating obje...
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Context 1
... process can be tuned to obtain bubbles with diameters of up to 100 μm or more, thus introducing the possibility of collecting particles from a large volume. On the other hand, the overall time of the process depends on the bubble size because small bubbles (1−4 μm) collapse in a few seconds, whereas bubbles with diameters up to 100 μm need time periods on the order of 1−2 min to collapse. 37 The technique is robust and reliable, and the laser pulses can be targeted on several structures with a high grade of reproducibility in order to compute a desired pattern, as shown in Figure 4. The video of the whole process (Video S3) is included in the Supporting ...
Context 2
... process can be tuned to obtain bubbles with diameters of up to 100 μm or more, thus introducing the possibility of collecting particles from a large volume. On the other hand, the overall time of the process depends on the bubble size because small bubbles (1−4 μm) collapse in a few seconds, whereas bubbles with diameters up to 100 μm need time periods on the order of 1−2 min to collapse. 37 The technique is robust and reliable, and the laser pulses can be targeted on several structures with a high grade of reproducibility in order to compute a desired pattern, as shown in Figure 4. The video of the whole process (Video S3) is included in the Supporting ...
Context 3
... process can be tuned to obtain bubbles with diameters of up to 100 μm or more, thus introducing the possibility of collecting particles from a large volume. On the other hand, the overall time of the process depends on the bubble size because small bubbles (1−4 μm) collapse in a few seconds, whereas bubbles with diameters up to 100 μm need time periods on the order of 1−2 min to collapse. 37 The technique is robust and reliable, and the laser pulses can be targeted on several structures with a high grade of reproducibility in order to compute a desired pattern, as shown in Figure 4. The video of the whole process (Video S3) is included in the Supporting ...
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... This strong interest stimulated the development of methods for intracellular recording of action potentials. Currently, the most promising results are represented by multi-electrode arrays (MEA) decorated with 3D nanostructures that were introduced in pioneering papers 7,8 , culminating with the recent work from the group of H. Park 9 and of F. De Angelis [10][11][12][13][14][15][16] . In these articles, they show intracellular recordings on electrodes refined with 3D nanopillars after electroporation and laser optoporation from different kind of cells. ...
This PhD thesis introduces the concept of meta-electrodes coupled with laser optoporation for high quality intracellular signals from hiPSCs-CM. These signals can be recorded on high-density commercial CMOS-MEAs from 3Brain characterized by thousands of electrode covered by a thin film of porous Platinum without any rework of the devices, 3D nanostructures or circuitry for electroporation. Subsequently, I attempted to translate these unique features of low invasiveness and reliability to other commercial MEA platforms, in order to develop a new tool for cardiac electrophysiological accurate recordings.
... There is a particular interest in multi-element NPs with unique and controllable properties. Alloy nanoparticles offer the possibility to tune functional properties (e.g., local surface plasmon resonance and/or adsorption energies) for sensing or catalytic applications [18,19].There are three basic ways to synthesize alloy NPs [20]. Chemical methods use (electro)chemical reduction [21,22], chemical precipitation [23], hydrothermal synthesis [23,24], etc. in the production process. ...
Nanoparticles of high purity can be produced from a variety of materials by pulsed laser ablation of solids in liquid. Composite nanoparticles are of great importance in various applications such as catalysis or biomedicine and the process of their formation is still a subject of intense research. In this work, gold/silver composite nanoparticles were synthesized in aqueous media by ns pulsed laser ablation of gold–silver multilayer targets with different absolute layer thicknesses and layer thickness ratios. The generated nanoparticles showed a log-normal distribution of sizes, with average diameter in the 20–40 nm range and standard deviation of 9–30 nm. By comparing the UV–VIS absorbance spectra of the nanoparticle colloids with two theoretical calculations (based on the Mie and the BEM model), it was found that there is a direct correlation between the average Au and Ag content of the nanoparticles and the composition of the films on the substrate. Assuming thermal ablation, our model calculations showed that there is a maximum thickness of the top layer up to which both layers can be ablated simultaneously and alloy nanoparticles can be produced.
... The laser-induced generation of bubbles involves multiple physical processes, such as heat transfer, optothermal conversion, phase transitions, gas diffusion, and pressure waves produced by nanoparticles [3,4,[7][8][9][10][11][12]. The bubble formation process is influenced by several factors, such as particle size, interparticle distance, type of medium, and laser power [5,7,8,[11][12][13][14][15]. ...
When a laser beam is irradiated on nanoparticles (optical absorbers) in a liquid, massive heat is generated, which causes vaporization of a nearby liquid, followed by the formation of bubbles. Despite the potential application of these bubbles for cancer diagnosis and therapy, solar energy harvesting, and local chemical reaction enhancement, little is known on how the size and interparticle distance of optical absorbers affect laser-induced bubble formation. Additionally, observing the bubble dynamics near nanomaterials is challenging due to their fast growth and immediate collapse. In this study, we trapped bubbles using hydrogels and investigated how their diameter changed with the size and interparticle distance of nanoparticles or their agglomerates and the energy level of laser irradiation. We found that the size of trapped bubbles increased with softer hydrogels, higher laser energy level, larger agglomerate size, and smaller interparticle distance among agglomerates. Based on these observations, we suggest that nanobubbles initially formed on nanoparticles merged to become microbubbles.
... 20 Moreover, a multitude of potential applications of these bubbles has been demonstrated, e.g. in catalysis, [21][22][23] medicine [24][25][26][27][28] or microfluidics. [29][30][31][32] This paper adds another surprising phenomenon to the rich phenomenology of physiochemical hydrodymanics involving plasmonic bubbles in binary liquids. Again, it builds on the preferential evaporation of one component of the binary liquid, which can lead to a bouncing bubble in the early growth stage via competing thermal and solutal Marangoni forces. ...
Multi-component fluids with phase transitions show a plethora of fascinating phenomena with rich physics. Here we report on a transition in the growth mode of plasmonic bubbles in binary liquids. By employing high-speed imaging we reveal that the transition is from slow evaporative to fast convective growth and accompanied by a sudden increase in radius. The transition occurs as the three-phase contact line reaches the spinodal temperature of the more volatile component leading to massive, selective evaporation. This creates a strong solutal Marangoni flow along the bubble which marks the beginning of convective growth. We support this interpretation by simulations. After the transition the bubble starts to oscillate in position and in shape. Though different in magnitude the frequencies of both oscillations follow the same power law , which is characteristic of bubble shape oscillations, with the surface tension σ as the restoring force and the bubble's added mass as inertia. The transitions and the oscillations both induce a strong motion in the surrounding liquid, opening doors for various applications where local mixing is beneficial.
... Although, in principle, this approach can ensure that all analyte molecules pass through the hot spots, as the molecules are still distributed in the solution and there is no concentrating mechanism, at any moment, the number of molecules in the hot spots is determined by the solution concentration. Active trapping mechanisms such as dielectrophoresis 29,30 , optical trapping [31][32][33] , and microbubble trapping 34 are promising ways to concentrate and deliver nano-objects and large biomolecules (e.g., proteins and DNA). However, these trapping mechanisms require external energy sources such as a laser or an applied voltage and are not suitable for relatively small molecules. ...
Nanophotonic resonators can confine light to deep-subwavelength volumes with highly enhanced near-field intensity and therefore are widely used for surface-enhanced infrared absorption spectroscopy in various molecular sensing applications. The enhanced signal is mainly contributed by molecules in photonic hot spots, which are regions of a nanophotonic structure with high-field intensity. Therefore, delivery of the majority of, if not all, analyte molecules to hot spots is crucial for fully utilizing the sensing capability of an optical sensor. However, for most optical sensors, simple and straightforward methods of introducing an aqueous analyte to the device, such as applying droplets or spin-coating, cannot achieve targeted delivery of analyte molecules to hot spots. Instead, analyte molecules are usually distributed across the entire device surface, so the majority of the molecules do not experience enhanced field intensity. Here, we present a nanophotonic sensor design with passive molecule trapping functionality. When an analyte solution droplet is introduced to the sensor surface and gradually evaporates, the device structure can effectively trap most precipitated analyte molecules in its hot spots, significantly enhancing the sensor spectral response and sensitivity performance. Specifically, our sensors produce a reflection change of a few percentage points in response to trace amounts of the amino-acid proline or glucose precipitate with a picogram-level mass, which is significantly less than the mass of a molecular monolayer covering the same measurement area. The demonstrated strategy for designing optical sensor structures may also be applied to sensing nano-particles such as exosomes, viruses, and quantum dots.
... This flow has been called a "bubble tweezer" and can be mainly induced by the difference of bubble/liquid interfacial tension (i.e., Marangoni flow), which depends on temperature gradients. These different biosensing applications leverage similar strategies in generating the surface bubble, where they use the photothermal conversion process occurring in three-dimensional (3D) patterns, 68 optically resistive thin films, 69 or metallic NPs. 5,70 On the one hand, the bubble tweezer can actively capture analytes in the solution and bring them to the threephase contact lines of the surface bubble. ...
... Plasmonic microbubbles are produced by immersed metal nanoparticles under laser irradiation due to plasmonic heating. They have received considerable attention, owing to their potential for numerous applications, such as biomedical diagnosis, cancer therapy [1][2][3][4][5], micromanipulation of molecules or particles dispersed in solutions [6][7][8] and locally enhanced chemical reactions [9,10]. A proper understanding of the dynamics of these plasmonic bubbles is therefore not only of fundamental interest, but also essential from a technological viewpoint as it might provide routes to tailor the formation and growth of the plasmonic bubbles. ...
Plasmonic bubbles are of great relevance in numerous applications, including catalytic reactions, micro/nanomanipulation of molecules or particles dispersed in liquids, and cancer therapeutics. So far, studies have been focused on bubble nucleation in pure liquids. Here we investigate plasmonic bubble nucleation in ternary liquids consisting of ethanol, water, and trans-anethole oil which can show the so-called ouzo-effect. We find that oil (trans-anethole) droplet plumes are produced around the growing plasmonic bubbles. The nucleation of the microdroplets and their organization in droplet plumes is due to the symmetry breaking of the ethanol concentration field during the selective evaporation of ethanol from the surrounding ternary liquids into the growing plasmonic bubbles. Numerical simulations show the existence of a critical Marangoni number Ma (the ratio between solutal advection rate and the diffusion rate), above which the symmetry breaking of the ethanol concentration field occurs, leading to the emission of the droplet plumes. The numerical results agree with the experimental observation that more plumes are emitted with increasing ethanol-water relative weight ratios and hence Ma. Our findings on the droplet plume formation reveal the rich phenomena of plasmonic bubble nucleation in multicomponent liquids and help to pave the way to achieve enhanced mixing in multicomponent liquids in chemical, pharmaceutical, and cosmetic industries.
... Plasmonic microbubbles are produced by immersed metal nanoparticles under laser irradiation due to plasmonic heating. They have received considerable attention, due to their potential for numerous applications, such as biomedical diagnosis, cancer therapy [1][2][3][4][5], micromanipulation of molecules or particles dispersed in solutions [6][7][8], and locally enhanced chemical reactions [9,10]. A proper understanding of the dynamics of these plasmonic bubbles is therefore not only of fundamental interest, but also essential from a technological viewpoint as it might provide routes to tailor the formation and growth of the plasmonic bubbles. ...
Plasmonic bubbles are of great relevance in numerous applications, including catalytic reactions, micro/nanomanipulation of molecules or particles dispersed in liquids, and cancer therapeutics. So far, studies have been focused on bubble nucleation in pure liquids. Here we investigate plasmonic bubble nucleation in ternary liquids consisting of ethanol, water, and trans-anethole oil, which can show the so-called ouzo effect. We find that oil (trans-anethole) droplet plumes are produced around the growing plasmonic bubbles. The nucleation of the microdroplets and their organization in droplet plumes is due to the symmetry breaking of the ethanol concentration field during the selective evaporation of ethanol from the surrounding ternary liquids into the growing plasmonic bubbles. Numerical simulations show the existence of a critical Marangoni number Ma (the ratio between solutal advection rate and the diffusion rate), above which the symmetry breaking of the ethanol concentration field occurs, leading to the emission of the droplet plumes. The numerical results agree with the experimental observation that more plumes are emitted with increasing ethanol-water relative weight ratios and hence Ma. Our findings on the droplet plume formation reveal the rich phenomena of plasmonic bubble nucleation in multicomponent liquids and help to pave the way to achieve enhanced mixing in multicomponent liquids in chemical, pharmaceutical, and cosmetic industries.
... Microbubbles, which possess low density, show the same properties as cheerios in a fluid environment, serving as an ideal carrier for designing novel floating drug delivery system. [26,27] However, a key bottleneck in applying microbubbles as drug carriers is their fabrication. Although microfluidic techniques, among others, have shown great promise in fabricating microemulsions or microparticles based on their precise manipulation of microscale fluids, the generation of microbubbles is difficult because of gas compression in the microfluidic microchannel. ...
Oral drug administration has an important role in medical treatment. Attempts to develop drug microcarriers with desired features for extended duration and improved absorption is highly sought. Herein, inspired by the physical phenomenon of the Cheerios effect, a novel microfluidic electrospray microbubble carrier is presented that can suspend and actively adhere to the stomach for durable oral delivery. Compared with conventional fabrication methods, the present strategy shows stability and controllability of the product. Benefiting from their uniform hollow structure, the resultant microbubbles present the same behavior of the Cheerios and can float in the gastric juice, adhere and remain to the stomach wall, which thus enhance the duration and absorption of the loaded drugs. Based on these, it is demonstrated as a proof of concept that the dexamethasone‐loaded hollow microbubbles can be applied to oral administration and remain suspended and adhered to the stomach of murine for more than 1 d, showing good therapeutic effect in treating lupus erythematosus. Thus, it is believed that the microbubbles floating system will find important values in long‐term oral administration.
... In a previous study, we have shown that plasmonic microbubbles in pure (monocomponent) liquids undergo four different phases: the initial giant vapor bubble (phase I), the oscillating bubble (phase II), water vaporizationdominated growth (phase III), and air diffusion-dominated growth (phase IV). 10 The bubble dynamics in these different phases depends on several factors, such as particle arrangement, 7 laser power, gas concentration, 10−12 and types of liquid. 13,14 The nucleation of a giant bubble is initiated by locally heating the liquid around the plasmonic particle up to the spinodal temperature. ...
The growth of surface plasmonic microbubbles in binary water/ethanol solutions is experimentally studied. The microbubbles are generated by illuminating a gold nanoparticle array with a continuous wave laser. Plasmonic bubbles exhibit ethanol concentration-dependent behaviors. For low ethanol concentrations (f_e) of < 67.5%, bubbles do not exist at the solid-liquid interface. For high f_e values of >80%, the bubbles behave as in pure ethanol. Only in an intermediate window of 67.5% < f_e < 80% do we find sessile plasmonic bubbles with a highly nontrivial temporal evolution, in which as a function of time three phases can be discerned. (1) In the first phase, the microbubbles grow, while wiggling. (2) As soon as the wiggling stops, the microbubbles enter the second phase in which they suddenly shrink, followed by (3) a steady reentrant growth phase. Our experiments reveal that the sudden shrinkage of the microbubbles in the second regime is caused by a depinning event of the three phase contact line. We systematically vary the ethanol concentration, laser power, and laser spot size to unravel water recondensation as the underlying mechanism of the sudden bubble shrinkage in phase 2.
