Patterning Of Microparticles Research Articles

Combinatory electric-field-guided deposition for spatial microparticles patterning

Spatial deposition and patterning of microparticles are crucial in chemistry, medicine, and biology. Existing technologies like electric force manipulation, despite precise trajectory control, struggle with complex and personalized patterns. Key challenges include adjusting the quantity of particles deposited in different areas and accurately depositing particles in non-continuous patterns. Here, we present a rational process termed combinatory electric-field-guided deposition (CED) for achieving spatially regulated microparticle deposition on insulative substrates. This process involves coating the substrates with insulating materials like PVP and positioning it on a relief-patterned negative electrode. The negative electric field generated by the electrode attracts microparticles, while the positive surface charges on the substrates repel microparticles, resulting in the formation of a potential well over the electrode area. Consequently, this configuration enables precise control over microparticle deposition without the need for direct contact with the substrate's surface, simplifying the process of switching masks to meet varying microparticle deposition requirements. Furthermore, we demonstrate the customization of patterned microparticles on superhydrophobic coatings to regulate cell distribution, as well as the successful loading of drug-laden microparticles onto antibacterial bandages to match the areas of skin lesions. These applications underscore the versatility of CED across chemical, medical, and bioengineering domains.

Phase holograms for the three-dimensional patterning of microparticles in a traveling wave field

Acoustic fields can generate radiation forces that can align particles in patterns. Forces from standing waves pattern particles in three dimensions (3-D) at either nodal or anti-nodal regions. These patterns can be utilized to form 3-D microstructures for applications in tissue engineering or fabrication of layered materials. However, standing waves require more than one transducer or a reflector, which can complicate implementation. Here, we developed a method to suspend and align microspheres using a traveling wave from a single transducer. Acoustic fields were shaped to align polyethylene microspheres mimicking tissue cells in parallel planes along the axis of the transducer. A Bessel-like beam was developed using diffraction theory and an iterative angular spectrum approach were used to design phase holograms to shape pressure fields. Gor’kov potential was used to calculate radiation forces while minimizing the axial forces to create a stable trap. The resulting pressure fields and particle patterns matched predictions with a similarity index >0.92, where 1 is a perfect match. The transverse radiation force was ten times each microsphere’s weight and comparable to the standing wave radiation forces. Next steps are in vivo implementation of cell patterning for tissue engineering. [Work supported by NIH K25-DK132416 and P01-DK043881.]

A simple, validated approach for design of two-dimensional periodic particle patterns via acoustophoresis

Two-dimensional patterning of microparticles enables a wide range of functional materials, including patterned energy storage electrodes, flexible electronics, and sensor arrays. Particle patterning via acoustics offers an attractive path to generate a wide variety of 2D periodic patterns that introduce tailorable hierarchical porosity, useful for controlling surface area, transport distances, and other properties. This method is most effective with micron scale particles and patterns of tens to hundreds of microns. To enable systematic exploration of the broad design space for such patterns, this work develops a model of 2D and 3D assembly of particles at high loadings and validates the obtained patterns against both experiments and more computationally intensive modeling techniques. Using this simple model, connections are mapped between input parameters (like actuation conditions, particle volume fraction, material properties) and output geometrical features (like void size and shape, pattern connectivity, and surface area) so that they can be tailored to given applications. The utility of this simple model is illustrated by predicting and then experimentally demonstrating new hierarchical patterns resulting from multiple waves of different frequencies interacting. These multiscale patterns offer the potential to lift the limits on surface area, diffusion distances, and other features.

Patterns of microparticles in blank samples: A study to inform best practices for microplastic analysis

Quality assurance and quality control (QA/QC) techniques are critical to analytical chemistry, and thus the analysis of microplastics. Procedural blanks are a key component of QA/QC for quantifying and characterizing background contamination. Although procedural blanks are becoming increasingly common in microplastics research, how researchers acquire a blank and report and/or use blank contamination data varies. Here, we use the results of laboratory procedural blanks from a method evaluation study to inform QA/QC procedures for microplastics quantification and characterization. Suspected microplastic contamination in the procedural blanks, collected by 12 participating laboratories, had between 7 and 511 particles, with a mean of 80 particles per sample (±SD 134). The most common color and morphology reported were black fibers, and the most common size fraction reported was 20–212 μm. The lack of even smaller particles is likely due to limits of detection versus lack of contamination, as very few labs reported particles <20 μm. Participating labs used a range of QA/QC techniques, including air filtration, filtered water, and working in contained/‘enclosed’ environments. Our analyses showed that these procedures did not significantly affect blank contamination. To inform blank subtraction, several subtraction methods were tested. No clear pattern based on total recovery was observed. Despite our results, we recommend commonly accepted procedures such as thorough training and cleaning procedures, air filtration, filtered water (e.g., MilliQ, deionized or reverse osmosis), non-synthetic clothing policies and ‘enclosed’ air flow systems (e.g., clean cabinet). We also recommend blank subtracting by a combination of particle characteristics (color, morphology and size fraction), as it likely provides final microplastic particle characteristics that are most representative of the sample. Further work should be done to assess other QA/QC parameters, such as the use of other types of blanks (e.g., field blanks, matrix blanks) and limits of detection and quantification.

Microfluidic Engineering of Crater-Terrain Hydrogel Microparticles: Toward Novel Cell Carriers.

Fabrication and application of novel anisotropic microparticles are of wide interest. Herein, a new method for producing novel crater-terrain hydrogel microparticles is presented using a concept of droplet-aerosol impact and regional polymerization. The surface pattern of microparticles is similar to the widespread "crater" texture on the lunar surface and can be regulated by the impact morphology of aerosols on the droplet surface. Methodological applicability was demonstrated by producing ionic-cross-linked (alginate) and photo-cross-linked (poly(ethylene glycol) diacrylate, PEGDA) microparticles. Additionally, the crater-terrain microparticles (CTMs) can induce nonspecific protein absorption on their surface to acquire cell affinity, and they were exploited as cell carriers to load living cells. Cells could adhere and proliferate, and a special cellular adhesion fingerprint was observed on the novel cell carrier. Therefore, the scalable manufacturing method and biological potential make the engineered microparticles promising to open a new avenue for exploring cell-biomaterial crosstalk.

Dynamic patterning of microparticles with acoustic impulse control

This paper describes the use of impulse control of an acoustic field to create complex and precise particle patterns and then dynamically manipulate them. We first demonstrate that the motion of a particle in an acoustic field depends on the applied impulse and three distinct regimes can be identified. The high impulse regime is the well established mode where particles travel to the force minima of an applied continuous acoustic field. In contrast acoustic field switching in the low impulse regime results in a force field experienced by the particle equal to the time weighted average of the constituent force fields. We demonstrate via simulation and experiment that operating in the low impulse regime facilitates an intuitive and modular route to forming complex patterns of particles. The intermediate impulse regime is shown to enable more localised manipulation of particles. In addition to patterning, we demonstrate a set of impulse control tools to clear away undesired particles to further increase the contrast of the pattern against background. We combine these tools to create high contrast patterns as well as moving and re-configuring them. These techniques have applications in areas such as tissue engineering where they will enable complex, high fidelity cell patterns.

CFD-DEM Coupling Model for Deposition Process Analysis of Ultrafine Particles in a Micro Impinging Flow Field.

Gas with ultrafine particle impaction on a solid surface is a unique case of curvilinear motion that can be widely used for the devices of surface coatings or instruments for particle size measurement. In this work, the Eulerian–Lagrangian method was applied to calculate the motion of microparticles in a micro impinging flow field with consideration of the interactions between particle to particle, particle to wall, and particle to fluid. The coupling computational fluid dynamics (CFD) with the discrete element method (DEM) was employed to investigate the different deposition patterns of microparticles. The vortex structure and two types of particle deposits (“halo” and “ring”) have been discussed. The particle deposition characteristics are affected both by the flow Reynolds number (Re) and Stokes number (stk). Moreover, two particle deposition patterns have been categorized in terms of Re and stk. Finally, the characteristics and mechanism of particle deposits have been analyzed using the particle inertia, the process of impinging (particle rebound or no rebound), vortical structures, and the kinetic energy conversion in two-phase flow, etc.

Effect of microchannel protrusion on the bulk acoustic wave-induced acoustofluidics: numerical investigation.

Acoustofluidics inside the microchannel has already found its wide applications recently. Acoustic streaming and radiation force are two underlying mechanisms that determine the trajectory of microparticles and cells in the manipulation. Critical particle size of viscous effects is found to be about 1.6µm in the conventional rectangular microchannel (W × H = 380m × 160m) at the frequency of 2MHz, below which the acoustic streaming dominants, and is independent of the driving voltage. In order to effectively adjust such a critical size, a approach is proposed and evaluated numerically to enhance the acoustic streaming by adding some protrusions (i.e., in the shape of a wedge, rod, half-ellipse) to the middle of the top or bottom wall. It is found that the resonant frequency and acoustic pressure will decrease and the acoustic streaming velocity will increase significantly, respectively, with the increase of protrusion height (up to 30µm while keeping the width the same as 8µm). Subsequently, trajectory motion patterns of microparticles have apparent changes in comparison to those inside the rectangular microchannel, and acoustic streaming can even dominate the motion of large microparticles (i.e., 10µm). As a result, the critical particle size could be increased up to 72.5µm. Furthermore, different protrusion shapes (i.e., wedge, rod, half-ellipse) on the top wall were compared. The sharpness of protrusion at its tip seems to determine the acoustic streaming velocity. The wedge attached to the bottom wall had higher resonant frequency and lower acoustic streaming velocity compared with the top wedge in the same dimension. The patterns of acoustic streaming and microparticle trajectory motion in the microchannel with dual wedges on the top and bottom walls are not the superposition of those of the top and bottom wedge individually. In summary, the geometry of the microchannel has a significant effect on the induced acoustofluidics by the bulk acoustic waves. A much larger acoustic streaming velocity is produced at the tip of the protrusion to change the critical size of microparticles between acoustic streaming and radiation force. It suggests that more applications of acoustofluidics (i.e., mixing and sonoporation) to microparticles and cells in various sizes are feasible by designing an appropriate geometry of the microchannel.

Acoustophoretic patterning of microparticles in a microfluidic chamber driven by standing Lamb waves

The contactless manipulation of microparticles and cells by using acoustic forces is important in many applications. However, multi-band acoustophoresis has been rarely investigated in the literature. In this Letter, we propose a microscale acoustofluidic system that has multiple orders of available Lamb modes for the acoustic trapping of microparticles at various frequencies. In our device, standing Lamb waves (SLWs) of specific orders can be selectively excited in a 300-μm-thick piezoelectric lithium-niobate (LiNbO3) crystal plate by a pair of interdigitated transducers (IDTs) at the corresponding frequency. We demonstrate the acoustophoretic trapping and patterning of 7-μm particles in a single acoustofluidic device with multiple available actuating frequencies. The approach to the proposed design and the working mechanisms are explained by using thin plate and a full-wave models that solve the dispersion relations and coupling fields of the piezoelectric SLW acoustofluidic system, respectively. Furthermore, we experimentally show that the stable and tight trapping of particles in the chamber can be achieved independently along two mutually orthogonal directions. This provides the essential ground for planar manipulations of microparticles and cells based on the proposed device. The results here can trigger more innovative designs and applications of acoustofluidic devices for microparticle manipulation and microfluidic mixing, with multi-frequency channels and a wide span of different actuating frequencies in one system.

Engineering the Surface Pattern of Microparticles: From Raspberry-like to Golf Ball-like.

Control of the shape and uniformity of colloid particles is essential for realizing their functionality in various applications. Herein, we report a facile approach for the synthesis of narrowly dispersed anisotropic microparticles with well-defined raspberry-like and golf ball-like surface patterns. First, we demonstrate that hybrid raspberry-like particles can be achieved through a one-pot polymerization method using glycidyl polyhedral oligomeric silsesquioxane (GPOSS) and pentaerythritol tetra(3-mercaptopropionate) (PETMP) as monomers. Varying the polymerization parameters such as catalyst loading, monomer concentration, and the molar ratio of monomers, we are able to regulate the sizes and surface protrusion numbers of these raspberry-like microparticles. The formation mechanism is attributed to a competition balance between thiol-epoxy reaction and thiol-thiol coupling reaction. The former promotes rapid formation of large core particles between PETMP and GPOSS droplets (which can serve as core particles), while the latter allows for generation of surface protrusions by PETMP self-polymerization, leading to the formation of raspberry-like surface patterns. Based on the different POSS contents in the surface protrusions and cores of the raspberry-like microparticles, we demonstrate that they can be used as precursors to produce microporous silica (sub)microparticles with golf ball-like morphology via pyrolysis subsequently. Overall, this work provides a facile yet controllable approach to synthesize narrowly dispersed anisotropic microparticles with diverse surface patterns.

Flexible and bendable acoustofluidics for particle and cell patterning

Surface Acoustic Wave (SAW) based microfluidic devices provide active techniques to manipulate fluid and particles, which can be used for precise and controllable patterning of microparticles and biological cells, with a high efficiency in a non-invasive and contact-free manner. This paper investigates flexible and bendable SAW microfluidic devices and explores the effects of bending and twisting of SAW devices on microparticle and cell patterning, using both experimental and numerical modelling. We showed that bending flexible SAW devices changes the distribution of particle pattern lines significantly. In devices with concave bending the particle pattern lines converge towards the centre of the curvature, whereas for devices with convex bending, they diverge away from it. Comparing the particle patterning using Lamb and Rayleigh wave devices with concave bending, we found that particle alignment is more efficient in the flexural mode Lamb wave device, whereas for the devices with convex bending, the particle patterning is more clear and regular when Rayleigh waves are used. We further investigated the effects of twisting the flexible SAW devices and observed that the particles are patterned into lines parallel to the deformed interdigital transducers (IDTs). We finally patterned yeast cells using our flexible SAW devices, and demonstrated the possibility of using our flexible acoustofluidic device for biomechanical systems such as body conforming technologies, wearable bio-sensors, and flexible point-of-care devices for personalized health monitoring.

Optimization of a Single-Particle Micropatterning System With Robotic nDEP-Tweezers

In this study, a system of automatic microparticle patterning that could enable the separation, trapping, and translation of single microbeads in liquid suspension using negative dielectrophoresis (DEP) tweezers was presented to form a single-bead pattern. A microchip with integrated electrodes was flipped and placed above the substrate through a micromanipulator. Microparticles laying on the substrate could be displaced to different positions relative to the electrodes on the microchip, and only the selected particles would be trapped by the electric fields generated from electrodes. Vision-based approaches were used to evaluate the necessary information, such as the gap distance and the positions of electrodes and microparticles in the image. A strategy for separating nearby particles was proposed to achieve single-bead patterning with high accuracy. A controller was used to guide the microparticles toward the position for trapping while avoiding flow disturbance. Different strategies were simulated to decrease the patterning time and find the minimum traveling distance and the best route of movement. The optimization problem is NP-hard. Hence, global optimization algorithms, such as genetic algorithm, particle swarm optimization, and ant colony optimization (ACO), were simulated, and the results were compared with those of the local optimization method. The comparison results showed that ACO obtained the best performance among the methods. The strategy for constructing high-quality microparticle patterns was also examined through experiments. Orange fluorescent polystyrene beads suspended in 6-aminohexanoic acid solution were considered and successfully patterned on a glass substrate by using the proposed system. <i>Note to Practitioners</i>&#x2014;Micropatterning is an effective tool for pharmaceutical research and drug discovery. However, the reliability of results depends on the quality of patterns. Existing approaches, such as microfluidic devices, are limited to create a pattern from one chip for single use, and the entire process is sealed and isolated from the environment. In this study, a multielectrode microchip combined with a vision-based micromanipulator is introduced to create a novel noncontact approach for microparticle patterning, which offers high flexibility and guarantees the quality of the constructed patterns. The electrodes on the chip can be selectively energized to determine the shape of the final pattern. A real-time screening is performed so that the micromanipulator will only guide the particles in good condition for selection. An optimization algorithm is implemented to aid the particle selection with the electrodes, allowing high-quality microparticle patterns to be constructed in a short time for various applications.

Large‐Scale Fabrication of 3D Scaffold‐Based Patterns of Microparticles and Breast Cancer Cells using Reusable Acoustofluidic Device

Spatial distribution of biological cells plays a key role in tissue engineering for reconstituting the cellular microenvironment, and recently, acoustofluidics are explored as a viable tool for controlling structures in tissue fabrication because of its good biocompatibility, low‐power consumption, automation capability, nature of non‐invasive, and non‐contact. Herein, a reusable acoustofluidic device is developed using surface acoustic waves for manipulating microparticles/cells to form a 3D matrix pattern inside a scaffold‐based hydrogel contained in a millimetric chamber. The 3D patterned and polymerized hydrogel construct can be easily and safely removed from the chamber using a proposed lifting technique, which prevent any physical damages or contaminations and promote the reusability of the chamber. The generated 3D patterns of microparticles and cells are numerically studied using a finite‐element method, which is well validated by the experimental results. The proposed acoustofluidic device is a useful tool for in vitro engineering 3D scaffold‐based artificial tissues for drug and toxicity testing and building organs‐on‐chip applications.

Modeling the initial phase of SARS-CoV-2 deposition in the respiratory tract mimicked by the 11C radionuclide.

The knowledge on the deposition and retention of the viral particle of SARS-CoV-2 in the respiratory tract during the very initial intake from the ambient air is of prime importance to understand the infectious process and COVID-19 initial symptoms. We propose to use a modified version of a widely tested lung deposition model developed by the ICRP, in the context of the ICRP Publication 66, that provides deposition patterns of microparticles in different lung compartments. In the model, we mimicked the "environmental decay" of the virus, determined by controlled experiments related to normal speeches, by the radionuclide 11C that presents comparable decay rates. Our results confirm clinical observations on the high virus retentions observed in the extrathoracic region and the lesser fraction on the alveolar section (in the order of 5), which may shed light on physiopathology of clinical events as well on the minimal inoculum required to establish infection.

Phase-Sensitive Pulse Sensor Using 2-D Active Plasmonics on Conformal Substrates

Real-time monitoring of the vital signals using flexible and portable biosensors plays an important role in future human life. However, there is most often a tradeoff between the improvement of the mechanical properties of these sensing chips and their sensitivity. In this study, we proposed 2-D polydimethylsiloxane (PDMS)–Au and silk–Au chips with microhole and microparticle patterns performing in an integrated platform of plasmonic ellipsometry. Under an external sinusoidal signal, we observed the regular dependence of the optical responses and plasmonic resonances on the frequency and not on the current. Using integrated plasmonic-ellipsometry technique and the phenomenon of active plasmonics, PDMS–Au microhole chip has demonstrated that $\Delta $ and $\Psi $ parameters became lesser by increasing the frequency and the resonance wavelength underwent a redshift. However, for silk–Au chip with inverse pattern of microparticle bumps, $\Delta $ and $\Psi $ had augmentation trend with respect to the frequency and the resonance wavelength shifted to shorter wavelengths. By optical and thermal analyses, we have demonstrated that this study can provide new insights into fabricating optically phase and amplitude sensitive biosensors based on conformal substrates with thermo-optical properties that can behave in redshift and blueshift regimes.

Manipulating the Deformation of Swelling Hydrogel Models by Microparticles

In recent years, the improvement of biomedical materials and their applications have gained much interest and been broadly discussed. Hydrogel, gelatin methacrylate (GelMA), is one of the applications with the greatest potential, such as cell culture, and studied by many researchers. In this study, a system consisting of GelMA film and the microparticles which can be aligned by applying an electric field is developed. The alignment of the microparticles can alter the curvature of the GelMA substrate. The proposed system which provides the mechanical stimulus to the cell attached on the system due to different deformation curvatures can be used as a carrier of cell culture. In order to reveal the relationship between the alignment of the microparticles and the resulting curvature, a user-defined element subroutine in the commercial finite element software package ABAQUS to predict the mechanical behavior, especially the curvature of the GelMA substrates, is developed. Different patterns of microparticles are simulated and the predicted curvatures of the GelMA substrates are compared with those measured in experiments, having good agreements. The results are expected to provide design guidance to the novel tissue engineering system, which is beneficial to the field of organ and tissue regeneration.

A deep learning approach for designed diffraction-based acoustic patterning in microchannels

Acoustic waves can be used to accurately position cells and particles and are appropriate for this activity owing to their biocompatibility and ability to generate microscale force gradients. Such fields, however, typically take the form of only periodic one or two-dimensional grids, limiting the scope of patterning activities that can be performed. Recent work has demonstrated that the interaction between microfluidic channel walls and travelling surface acoustic waves can generate spatially variable acoustic fields, opening the possibility that the channel geometry can be used to control the pressure field that develops. In this work we utilize this approach to create novel acoustic fields. Designing the channel that results in a desired acoustic field, however, is a non-trivial task. To rapidly generate designed acoustic fields from microchannel elements we utilize a deep learning approach based on a deep neural network (DNN) that is trained on images of pre-solved acoustic fields. We use then this trained DNN to create novel microchannel architectures for designed microparticle patterning.

Two-Photon Lithographic Patterning of DNA-Coated Single-Microparticle Surfaces.

The spatially defined functionalization of microparticles with asymmetric shape-controlled nucleic acid patterns is a major challenge in materials science. The asymmetric patterning of microparticles is important to allow the controlled fabrication of crystalline lattices or controlled aggregates of microparticles. We present the combination of two-photon lithography and photocleavable o-nitrobenzylphosphate ester nucleic acid coating-modified microparticles as a versatile means to asymmetrically pattern single microparticle surfaces. The two-photon patterning of microparticles with predesigned nucleic acid structures of different sizes (700 nm to 2.8 μm) and shapes (circles, rings, triangles, and squares) are demonstrated. In addition, complex patterned domains consisting of two different asymmetric nucleic acid domains are fabricated by the controlled Z-positioning of the microparticles in respect to the two-photon irradiation sources. In addition, the two-photon lithographic patterning of the photocleavable DNA coating allows the generation of functional nucleic acid domains for the photostimulated activation of the catalytic hybridization assembly (CHA) of branched nucleic acid structures on single microparticles.

Characterization of starch and gum arabic-maltodextrin microparticles encapsulating acacia tannin extract and evaluation of their potential use in ruminant nutrition.

ObjectiveThe use of tannin extract and other phytochemicals as dietary additives in ruminants is becoming more popular due to their wide biological actions such as in methane mitigation, bypass of dietary protein, intestinal nematode control, among other uses. Unfortunately, some have strong astringency, low stability and bioavailability, and negatively affecting dry matter intake and digestibility. To circumvent these drawbacks, an effective delivery system may offer a promising approach to administer these extracts to the site where they are required. The objectives of this study were to encapsulate acacia tannin extract (ATE) with native starch and maltodextrin-gum arabic and to test the effect of encapsulation parameters on encapsulation efficiency, yield and morphology of the microparticles obtained as well as the effect on rumen in vitro gas production.MethodsThe ATE was encapsulated with the wall materials, and the morphological features of freeze-dried microparticles were evaluated by scanning electron microscopy. The in vitro release pattern of microparticles in acetate buffer, simulating the rumen, and its effect on in vitro gas production was evaluated.ResultsThe morphological features revealed that maltodextrin/gum-arabic microparticles were irregular shaped, glossy and smaller, compared with those encapsulated with native starch, which were bigger, and more homogenous. Maltodextrin-gum arabic could be used up to 30% loading concentration compared with starch, which could not hold the core material beyond 15% loading capacity. Encapsulation efficiency ranged from 27.7%±6.4% to 48.8%±5.5% in starch and 56.1%±4.9% to 64.8%±2.8% in maltodextrin-gum arabic microparticles. Only a slight reduction in methane emission was recorded in encapsulated microparticles when compared with the samples containing only wall materials.ConclusionBoth encapsulated products exhibited the burst release pattern under the pH conditions and methane reduction associated with tannin was marginal. This is attributable to small loading percentages and therefore, other wall materials or encapsulation methods should be investigated.

Standard and inverse microscale Chladni figures in liquid for dynamic patterning of microparticles on chip

We report on experimental demonstrations of the first sub-100 μm scale standard and inverse Chladni figures in both one- (1D) and two-dimensional (2D) fashions in liquid, and on exploiting these micro-Chladni figures for patterning microparticles on chip, via engineering multimode micromechanical resonators with rich, reconfigurable 1D and 2D mode shapes. Silica microparticles (1–8 μm in diameter) dispersed on top of resonating doubly-clamped beams (100 × 10 × 0.4 μm3) are observed to aggregate at antinodal points, forming 1D inverse Chladni figures, while microbeads atop square trampoline resonators (50 × 50 × 0.2 μm3) cluster at nodal lines/circles, creating 2D standard Chladni figures such as “,” “○,” “×,” and “\.” These observations suggest two distinct micro-Chladni figure patterning mechanisms in liquid. Combining analytical and computational modeling, we elucidate that streaming flow dominates the inverse Chladni pattern formation in the 1D beam experiments, while vibrational acceleration dictates the standard Chladni figure generation in the 2D trampoline experiments. We further demonstrate dynamical patterning, switching, and removal of 2D micro-Chladni figures in swift succession by simply controlling the excitation frequency. These results render new understandings of Chladni patterning genuinely at the microscale, as well as a non-invasive, versatile platform for manipulating micro/nanoparticles and biological objects in liquid, which may enable microdevices and functional device-liquid interfaces toward relevant sensing and biological applications.