Artificial acoustic shock wave impact study on primary amino acids: A case study of L-cysteine – crystal structure, optical properties and surface morphology aspects

Acoustic shock-engineered 6-methylcoumarin as the active antibacterial agent.

Toward online dose reconstruction in phantom using deep learning-based X-ray-induced acoustic imaging for X-ray FLASH radiotherapy

Detection of cyanobacteria MC-LR using modulated surface acoustic wave (SAW) sensor for enhanced sensitivity, selectivity and limit of detection

This research presents a novel procedure of using stationary waves generated with the impulse-response test using semi-noncontact measurements and relatively high-frequency bandwidths. The time histories of vibrations are recorded with a condenser microphone over a regular square grid at the surface of a concrete plate. The analyses were performed on the normalized time-domain response at each test location. Using the impact-normalized time-domain responses, oscillatory modes are obtained through empirical mode decomposition. The first oscillatory mode of each normalized response is converted back to the frequency domain, and its maximum amplitude is shown to be an accurate defect indicator. The defects are effectively delineated spatially, and their intensity is estimated by using extreme value outlier analysis. The physical basis for the proposed procedure is demonstrated by using a finite-element model that indicates that stationary acoustic waves are generated by an impact above the concrete surface. An experimental specimen with simulated defects in the form of shallow and deep delamination, debonding, and honeycomb was used to validate the proposed procedure. Using the proposed experimental and the new data analysis procedure, the defect indicator was able to detect the delamination at two different depths, debonding, and honeycomb in the lab-scale concrete plate. The level of accuracy of the damage detection was comparable to that of more refined yet time-consuming ultrasonic shear-wave echo method. The defect indicator calculated with the proposed signal processing algorithm was found to be robust to the ambient noise that can influence the measurements with the condenser microphone.

Cultivated meat is anticipated to offer a more sustainable and environmentally responsible alternative to conventional livestock production. However, its commercial viability relies on the development of scalable and cost-effective bioprocesses. While notable advancements have been made in upstream operations, such as bioreactor design and media formulation, downstream processing remains an underexplored area. This review highlights the need for scalable, low-shear cell harvesting methods as well as media recycling strategies to reduce cost and waste. Separation technologies from adjacent industries are evaluated for their applicability to cultivated meat production, including centrifugation, filtration, acoustic wave separation, and hydrocyclones for cell harvest. To support continuous bioprocessing and align with circular bioeconomy principles, innovative approaches for the selective removal of metabolic inhibitors from spent media are also explored. Techniques such as adsorption, electrochemical treatment, and membrane-based separations are discussed for their potential to enable media reuse in high cell density cultures. By integrating downstream process technologies into closed-loop systems, cultivated meat production can achieve enhanced sustainability, reduced operational costs, and improved scalability. The application of these purification and cell harvest strategies to continuous culture platforms may provide a low-waste, sustainable platform to maximise cultivated meat production. By focusing on the separation challenges associated with the manufacture of cultivated meat, this review ultimately highlights the need for further downstream processing research if cultivated meat products are to become a commercial reality. • Potential strategies for cultivated meat downstream processing – Focus on scalable cell harvesting and media recycling methods to enhance efficiency and viability. • Continuous bioprocessing – Integrate downstream processing into closed-loop systems to maintain high cell densities, reduce waste, and lower production costs. • Role of downstream processing in the bio-circular economy – Support waste valorisation, nutrient recovery, and resource efficiency, linking cultivated meat production with precision fermentation.

High-precision wide-range temperature measurement by annular interdigital transducer-based surface acoustic wave sensors

We report the development of a sensitive biosensing platform based on a shear-horizontal surface acoustic wave (SH-SAW) device and paper fluidics, with the potential to be used outside centralized laboratory settings. Systematic research on the biorecognition surface, blocking agent, fluidics and measuring unit allowed us to transform a laboratory-based method into a field-deployable device. As a proof-of-concept, the platform was used for the detection of SARS-CoV-2 anti-spike antibodies on a surface-immobilized spike protein, tested in both simulated and human blood serum samples. A poly-L-lysine (PLL) layer was selected as a biocompatible surface for spike protein immobilization; the polymer layer can be easily removed through gentle mechanical rubbing, allowing regeneration and multiple uses of the sensing device. This surface, combined with novel paper-based capillary fluidics, enabled real-time monitoring of spike antibody binding via acoustic wave phase measurements in the range of 1-100 nM antibodies in 1% v/v serum. Further acoustic wave amplitude amplification and a tenfold improvement in the detection limit (0.1 nM) were achieved by the use of gold nanoparticles conjugated with a secondary antibody. This optimized assay was successfully evaluated in a small pilot clinical study of 20 patient samples. Our new SH-SAW immunosensor exhibited sensitivity and specificity comparable to commercial systems with standard fluidics and instrumentation; importantly, its limit of detection is better than the clinically relevant value of ∼11 RU mL-1. This portable, low-cost platform, combining a pocket-size network analyzer with disposable paper fluidics and a regenerable sensing surface, offers a promising solution for quantitative antibody detection near or at the point-of-care.

Extracorporeal shockwave therapy (ESWT) acts as an acoustic wave via momentum transfer and mechanotransduction in aplethora of regenerative ways. Scaphoid non-unions benefit from high-energetic focused ESWT. In lunate necrosis aka Morbus Kienboek focused high-energetic ESWT can reduce pain and improve MRI. In CMC1 osteoarthritis focused ESWT appears to be clinically equal to intraarticular ultrasound-guided hyaluronic acid injection with more pronounced effects 6 months after therapy in the ESWT group. Tendinopathies of the hand can be treated with both, radial and focused ESWT, especially in symptomatic trigger finger and de Quervain tendinopathy. In symptomatic painful Dupuytren disease, focused high-energetic ESWT can reduce pain and slow down progression of the disease.

Topological logic gates based on valley-locked interface states of acoustic and electromagnetic waves in two-dimensional phoxonic crystals

The orbital Hall effect, which generates orbital currents, has emerged as a key mechanism for the angular momentum transport in solids. Its acoustic analogue, the acoustic orbital Hall effect, has recently been observed in which a surface acoustic wave (SAW) drives an orbital current transverse to its propagation direction. However, their microscopic mechanism has remained elusive. Here, we reveal that the acoustic orbital Hall effect in Ti is driven by an acoustoelectric mechanism. Using Ti/Ni bilayers on a piezoelectric LiNbO3 substrate, we observe a clear phase shift in the magnetic field angle dependence of the acoustic orbital Hall voltage as the SAW propagation direction is varied relative to the crystallographic axes. This behavior is consistent with orbital current generation by the in-plane electric field associated with the acoustoelectric evanescent wave. Moreover, from simultaneously measured acoustic orbital Hall and acoustic orbital pumping signals, we determined the efficiency of converting lattice dynamics into orbital transport.

Acoustic forces offer a powerful, contact-free modality for manipulating particles and fluids within microfluidic lab-on-a-chip systems. However, realizing the full potential of acoustic manipulation has been constrained by conventional cleanroom-based fabrication methods. Typically formed from high-acoustic-impedance materials like silicon or glass, these processes yield devices with limited design complexity owing to the planar channel geometries inherent in micromachining. Here, we introduce a class of polymer-based acoustofluidic platforms fabricated using micro-digital light processing (μDLP) 3D printing. In contrast to micromachining, this additive manufacturing approach enables complex, truly three-dimensional (3D) microfluidic architectures in a monolithic device form factor. We demonstrate strategies to overcome challenges associated with low-acoustic-impedance polymer resins and establish design rules based on precise control over channel and surrounding material dimensions (e.g., wall thicknesses) to achieve robust acoustofluidic functions including efficient sharp-edge-based mixing and effective particle focusing using a bulk acoustic wave resonance mode. By leveraging the design freedom provided by additive manufacturing, we fabricated an integrated, monolithic device driven by a single piezoelectric element that sequentially performs acoustic mixing and focusing within spatially distinct regions enabled by engineered variations in the 3D channel structure. This work establishes μDLP additive manufacturing as a key enabler for next generation acoustofluidic platforms by demonstrating how true 3D architectural control over channel geometry can yield integrated, multifunctional polymer acoustofluidic devices with an expanded functional design space.

Multi-parameter controlled acoustofluidic assembly of colloidal and cellular structures.

Optical ultrasound detection enables greater miniaturization than conventional piezoelectric transducers while preserving high sensitivity. Although sub-micron silicon photonics detectors have been demonstrated, image artifacts caused by surface acoustic waves interference remain a key challenge. Polymer detectors offer better acoustic coupling, yet they have been limited to tens of micrometers in size because of optical confinement requirements. Here we overcome that limit with the smallest polymer resonator built on an optical fiber, using a 6 µm thick polymer cavity on a tapered single mode fiber tip. The detector achieved a bandwidth of about 150 MHz and a noise equivalent pressure density of about 1.5 mPa.Hz-1/2. Imaging experiments yielded 7 µm axial and 17 µm lateral resolution, with high fidelity performance that surpassed piezoelectric and state of the art optical detectors. This combination of broad bandwidth, artifact free imaging, and manufacturability makes the detector ideal for optoacoustic mesoscopy (OptAM) applications.

Understanding how acoustic waves interact with soft matter is critical for developing new strategies for dynamic control, actuation, sensors, and manipulation at small scales. A major challenge in soft matter and microrobotics is how to achieve fast, precise, and remotely controlled actuation at the microscale without sacrificing compliance or biocompatibility. Here, we introduce wireless artificial microcilia based on acoustically activated soft hydrogel microstructures inspired by Venus flytrap and vorticella. The structures, termed SonoGrippers, consist of dual microcilia (≤120 µm length) with outward-facing sharp tips. Upon acoustic excitation, SonoGrippers deliver ultrafast (~2 ms), reversible, and controllable actuation, enabling remote attraction, gripping, and release of objects. By tuning structural designs and acoustic parameters, SonoGrippers exhibit diverse deformation modes and tunable response dynamics, allowing adaptable gripping performance across various application scenarios. Proof-of-concept demonstrations with stationary and mobile biological samples confirm their robust functionality. Combining simple fabrication, additive-free operation, wireless rapid control, and biocompatibility, SonoGrippers provide a promising platform toward next-generation biomedical manipulation, soft microrobotics, and bioengineering applications.

Predicting blast-induced ground vibration (BIGV) in surface mining is crucial for ensuring environmental safety. Conventional empirical models often require risky and costly site-specific trial blasts. This study intends to develop a pre-blast assessment framework by correlating laboratory-derived acoustic properties with field-monitored vibration data from a limestone mine. The methodology integrates comprehensive geomechanical and non-destructive Ultrasonic Pulse Velocity (UPV) testing to characterise the dynamic response of the rock mass. Peak Particle Velocity (PPV) and frequency are monitored for multiple production blasts. The laboratory UPV tests provided key insights into the material's dynamic response, which were validated by fundamental wave-mechanical relationships. Results confirmed a strong linear correlation (R2 = 0.82) between specimen length and particle displacement, supporting the theoretical strain-kinematic relationship, while wave propagation behaviour was analysed using power-law relationships to describe geometric spreading and material attenuation. The derived attenuation coefficient of 0.675 is lower than the empirical decay exponent of 1.46 (derived from the USBM model), indicating a relatively conservative representation of vibration attenuation. Model performance was evaluated using statistical metrics, showing comparable predictive capability to the USBM model in terms of R², RMSE, and MAE, with improved representation of material-specific attenuation behaviour. The proposed framework integrates geomechanical principles with mathematical modelling to develop a physically informed alternative to purely empirical approaches. This hybrid BIGV prediction method can be applied at the pre-blast planning stage, thereby improving prediction reliability and supporting safer, more efficient mining operations.

High-sensitivity cantilever beam-type surface acoustic wave stress-strain sensor

Automated ultrasonic inspection of diffusion-welded components with variable curvature and thickness is challenging due to difficulties in focusing acoustic waves on curved weld interfaces and the small size of defects, especially when accurate CAD models are unavailable. This study aims to develop a methodology for reliable inspection of such components. An integrated system combining laser profile scanning and multi-axis robotic ultrasonic testing is developed, synchronization among surface conformal data (surface-fitting information describing the geometry of the scanned surface), ultrasonic signals, and robot motion states is resolved in the proposed system design. Adaptive ultrasonic scanning trajectories are generated based on laser profiles to accommodate unknown curved surfaces. Ultrasonic field simulations determine suitable transducer parameters, and the effects of surface curvature and scanning trajectory accuracy on defect echoes are analyzed, ensuring the reliability of inspection results. Multi-axis robotic C-scan experiments are conducted on titanium alloy diffusion-welded curved blade specimens. The proposed methodology enables automated inspection of complex curved diffusion welds. Experimental results show effective detection of internal defects, with improved inspection stability and reliability. This study introduces an integrated laser-ultrasonic inspection approach that explicitly addresses the synchronization of multi-source data and enables adaptive scanning on unknown curved surfaces, providing a reliable approach for ultrasonic inspection of complex curved diffusion-welded components.

Label-free and effective sorting of red and white blood cells based on their physical properties is crucial for subsequent single-cell analysis or immune cell engineering applications. However, cell sorting relying on the physical effects of one single physical property remains highly challenging. This paper proposes a cell sorting method based on a focused traveling surface acoustic wave (FTSAW)-based acoustofluidic chip, which leverages the ability of FTSAW acoustofluidics to comprehensively respond to multiple physical characteristics of cells (e.g., size, density, morphology, and deformability), and furthermore allows for precise setting of the action area range and adjustment of the action intensity. In experiments, a pair of focused interdigital transducers (FIDTs, characteristic frequency: 128.6 MHz) on the substrate of lithium niobate and a typical microchannel structure (single-side sheath flow focusing followed by bifurcated sorting, i.e., "two streams merging into one and then splitting into two") were designed and fabricated. Parameter optimization experiments for separation and sorting were conducted on 3 μm and 5 μm polystyrene (PS) beads, as well as red and white blood cell samples after sheath flow focusing. The results indicate that the FTSAW-based acoustofluidic chip enabled white blood cell sorting with high purity (∼90%) and high biological viability (∼98%). This study demonstrates the potential of the FTSAW-based acoustofluidic chip for cell sorting. Owing to its easy integration and advantages (non-contact operation, no sieve pore clogging, broad compatibility with cell culture media), it is expected to serve as a key pre-processing technology in microfluidic systems for single-cell analysis or cell engineering.

Electrical isolation is critical to ensure safety and minimize electromagnetic interference (EMI), yet existing methods struggle to simultaneously transmit power and signals through a unified channel. Here we demonstrate a mechanically-isolated gate driver based on microwave-frequency surface acoustic wave (SAW) device on lithium niobate that achieves galvanic isolation of 2.75 kV with ultralow isolation capacitance (0.032 pF) over 1.25 mm mechanical propagation length, delivering 13.4 V open-circuit voltage and 44.4 mA short-circuit current. We demonstrate isolated gate driving for a gallium nitride (GaN) high-electron-mobility transistor, achieving a turn-on time of 108.8 ns and validate its operation in a buck converter. In addition, our SAW device operates over an ultrawide temperature range from 0.5 K (-272.6 °C) to 544 K (271 °C). The microwave-frequency SAW devices offer inherent EMI immunity and potential for heterogeneous integration on multiple semiconductor platforms, enabling compact, high-performance isolated power and signal transmission in advanced power electronics.