Concentration of Microparticles/Cells Based on an Ultra-Fast Centrifuge Virtual Tunnel Driven by a Novel Lamb Wave Resonator Array.

The µTAS/LOC, a highly integrated microsystem, consolidates multiple bioanalytical functions within a single chip, enhancing efficiency and precision in bioanalysis and biomedical operations. Microfluidic centrifugation, a key component of LOC devices, enables rapid capture and enrichment of tiny objects in samples, improving sensitivity and accuracy of detection and diagnosis. However, microfluidic systems face challenges due to viscosity dominance and difficulty in vortex formation. Acoustic-based centrifugation, particularly those using surface acoustic waves (SAWs), have shown promise in applications such as particle concentration, separation, and droplet mixing. However, challenges include accurate droplet placement, energy loss from off-axis positioning, and limited energy transfer from low-frequency SAW resonators, restricting centrifugal speed and sample volume. In this work, we introduce a novel ring array composed of eight Lamb wave resonators (LWRs), forming an Ultra-Fast Centrifuge Tunnel (UFCT) in a microfluidic system. The UFCT eliminates secondary vortices, concentrating energy in the main vortex and maximizing acoustic-to-streaming energy conversion. It enables ultra-fast centrifugation with a larger liquid capacity (50 µL), reduced power usage (50 mW) that is one order of magnitude smaller than existing devices, and greater linear speed (62 mm/s), surpassing the limitations of prior methods. We demonstrate successful high-fold enrichment of 2 µm and 10 µm particles and explore the UFCT's potential in tissue engineering by encapsulating cells in a hydrogel-based micro-organ with a ring structure, which is of great significance for building more complex manipulation platforms for particles and cells in a bio-compatible and contactless manner.

Low-Voltage High-Frequency Lamb-Wave-Driven Micromotors.

By leveraging the benefits of a high energy density, miniaturization and integration, acoustic-wave-driven micromotors have recently emerged as powerful tools for microfluidic actuation. In this study, a Lamb-wave-driven micromotor is proposed for the first time. This motor consists of a ring-shaped Lamb wave actuator array with a rotor and a fluid coupling layer in between. On a driving mechanism level, high-frequency Lamb waves of 380 MHz generate strong acoustic streaming effects over an extremely short distance; on a mechanical design level, each Lamb wave actuator incorporates a reflector on one side of the actuator, while an acoustic opening is incorporated on the other side to limit wave energy leakage; and on electrical design level, the electrodes placed on the two sides of the film enhance the capacitance in the vertical direction, which facilitates impedance matching within a smaller area. As a result, the Lamb-wave-driven solution features a much lower driving voltage and a smaller size compared with conventional surface acoustic-wave-driven solutions. For an improved motor performance, actuator array configurations, rotor sizes, and liquid coupling layer thicknesses are examined via simulations and experiments. The results show the micromotor with a rotor with a diameter of 5 mm can achieve a maximum angular velocity of 250 rpm with an input voltage of 6 V. The proposed micromotor is a new prototype for acoustic-wave-driven actuators and demonstrates potential for lab-on-a-chip applications.

Microfluidic confined acoustic streaming vortex for liposome synthesis.

Liposomes have garnered significant attention owing to their favorable characteristics as promising carriers. Microfluidic based hydrodynamic flow focusing, or micro-mixing approaches enable precise control of liposome size during their synthesis due to the comparable size scale. However, current microfluidic approaches still have issues such as high flow rate dependency, complex chip structures, and ease of clogging. Herein, we present a novel microfluidic platform for size-tunable liposome synthesis based on an ultra-high-frequency acoustic resonator. By designing the shape and orientation of the acoustic resonator in the three-phase laminar flow, it combined the features of both hydrodynamic flow focusing and rapid micro-mixing. The distribution of lipid precursor solution in laminar flow and the mixing conditions could be regulated by the confined acoustic streaming vortex. We successfully synthesize liposomes with adjustable sizes and narrow size distributions. Notably, this platform regulates the product size by adjusting only the input power, which is less dependent on the flow rate. Furthermore, the vortex-like fluid flow generated along the device edge effectively prevents precipitation due to excessive lipid concentration or contact with the wall.

Acoustofluidic manipulation for submicron to nanoparticles.

Particles, ranging from submicron to nanometer scale, can be broadly categorized into biological and non-biological types. Submicron-to-nanoscale bioparticles include various bacteria, viruses, liposomes, and exosomes. Non-biological particles cover various inorganic, metallic, and carbon-based particles. The effective manipulation of these submicron to nanoparticles, including their separation, sorting, enrichment, assembly, trapping, and transport, is a fundamental requirement for different applications. Acoustofluidics, owing to their distinct advantages, have emerged as a potent tool for nanoparticle manipulation over the past decade. Although recent literature reviews have encapsulated the evolution of acoustofluidic technology, there is a paucity of reports specifically addressing the acoustical manipulation of submicron to nanoparticles. This article endeavors to provide a comprehensive study of this topic, delving into the principles, apparatus, and merits of acoustofluidic manipulation of submicron to nanoparticles, and discussing the state-of-the-art developments in this technology. The discourse commences with an introduction to the fundamental theory of acoustofluidic control and the forces involved in nanoparticle manipulation. Subsequently, the working mechanism of acoustofluidic manipulation of submicron to nanoparticles is dissected into two parts, dominated by the acoustic wave field and the acoustic streaming field. A critical analysis of the advantages and limitations of different acoustofluidic platforms in nanoparticles control is presented. The article concludes with a summary of the challenges acoustofluidics face in the realm of nanoparticle manipulation and analysis, and a forecast of future development prospects.

Changes in TNF-α, IL-33, and MIP-1α before and after artificial liver support treatment and their prognostic value.

OBJECTIVE: To investigate the effect of ALST (artificial liver support treatment) on inflammatory factors and prognosis in patients with ACLF (acute-on-chronic liver failure). METHODS: Data of ACLF patients admitted to the No. 2 People's Hospital of Lanzhou from June 2020 to January 2023 were retrospectively analyzed. Patients were compared before and after ALST in terms of ALT (Alanine Aminotransferase), AST (Aspartate Aminotransferase), TBil (Total Bilirubin), Cr (Creatinine), INR (International Normalized Ratio), MELD (Model for End-Stage Liver Disease) scores, as well as TNF-α (Tumor Necrosis Factor-α), IL-33 (Interleukin-33), and MIP-1α (Macrophage Inflammatory Protein-1 α) levels. The ROC (receiver operating characteristic) curve was used to analyze the efficacy of the above indicators in predicting 90-day mortality in patients. RESULTS: After the treatment, the levels of ALT, AST, TBil, Cr, INR, and MELD score were significantly lower than those before treatment (all P<0.001). Also, the levels of TNF-α, IL-33, and MIP-1α were substantially lower than those before treatment (all P<0.001). TNF-α, IL-33, and MIP-1α were positively correlated with MELD score before and after the treatment (all P<0.01). TNF-α, IL-33, MIP-1α, and MELD score were significantly higher in the death group than in the survival group (all P<0.01). The ROC curves showed that MELD (AUC=0.857), TNF-α (AUC=0.836), IL-33 (AUC=0.749), and MIP-1α (AUC=0.746) had high efficacy in predicting patients' 90-day mortality. CONCLUSION: ALST can significantly reduce TNF-α, IL-33, and MIP-1α levels in patients with ACLF, and postoperative TNF-α, IL-33, and MIP-1α levels have a high predictive value for patients' prognosis.

Microstructure, Mechanical and Tribological Properties of Si3N4/Mo-Laminated Composites.

(1) Background: the applications of ceramic materials in a friction pair and a moving pair are limited, just because of their poor toughness and unsatisfactory tribological characteristics. In view of this, Mo as a soft metal layer was added into a Si3N4 matrix to improve its toughness and tribological characteristics. (2) Methods: The microstructure and metal/ceramic transition layer were examined using X-ray diffraction, scanning electron microscope, electron dispersive X-ray spectroscopy, and Vickers hardness. Bending strength and fracture toughness were also measured. Tribological characteristics were obtained on the pin-on-disc wear tester. (3) Results: It can be found that the multilayer structure could improve the fracture toughness of laminated composite compared with single-phase Si3N4, but the bending strength was significantly reduced. Through microstructure observation, the transition layer of Si3N4/Mo-laminated composite was revealed as follows: Si3N4→MoSi2→Mo5Si3→Mo3Si→Mo. Moreover, the addition of the Mo interface to silicon nitride ceramic could not significantly improve the tribological properties of Si3N4 ceramic against titanium alloy in seawater, and the friction coefficients and wear rates of the sliding pairs increased with the increase in load. (4) Conclusions: The process failed to simultaneously improve the comprehensive mechanical properties and tribological performance of Si3N4 ceramic by adding Mo as the soft interfacial layer. However, the utilization of metal interfacial layers to enhance the toughness of ceramics was further recognized and has potential significance for the optimization of ceramic formulation.

An Ultra-Low Power, Small Size and High Precision Indoor Localization System Based on MEMS Ultrasonic Transducer Chips.

The development of Internet of Things (IoT) requires demanding accurate and low-power indoor localization. In this article, a high-precision 3-D ultrasonic indoor localization system with ultralow power is proposed. A new piezoelectric micromachined ultrasonic transducer (PMUT) chip with a slotted membrane is designed and fabricated as a receiver, breaking the dilemma of low resonant frequency and wide field of view required for indoor localization. The system works based on the time difference of arrival (TDoA), and an improved quantum genetic algorithm (QGA) is used to estimate the location. The results show that the system achieves centimeter-level positioning precision, which is among the best solutions nowadays. Due to the high performance and small size endowed by the PMUT, the receiver footprint reaches as small as 0.25 cm2 and power consumption could reach as low as 0.1 mW, which are far better than that of current indoor localization systems.

Phase separation of a nonionic surfactant aqueous solution in a standing surface acoustic wave for submicron particle manipulation.

Acoustic manipulation of submicron particles in a controlled manner has been challenging to date because of the increased contribution of acoustic streaming, which leads to fluid mixing and homogenization. This article describes the patterning of submicron particles and the migration of their patterned locations from pressure nodes to antinodes in a non-ionic surfactant (Tween 20) aqueous solution in a conventional standing surface acoustic wave field with a wavelength of 150 µm. Phase separation of the aqueous surfactant solution occurs when they are exposed to acoustic waves, probably due to the "clouding behavior" of non-ionic surfactant. The generated surfactant precipitates are pushed to the pressure antinodes due to the negative acoustic contrast factor relative to water. Compared with the mixing appearance in pure water media, the patterning behavior of submicron particles with a diameter of 300 nm dominated by acoustic radiation force is readily apparent in an aqueous solution with 2% volumetric concentration of Tween 20 surfactant, thanks to the suppression effect of acoustic streaming in inhomogeneous fluids. These submicron particles are first pushed to acoustic pressure nodes and then are migrated to antinodes where the surfactant precipitates stay. More attractively, the migration of acoustically patterned locations is not only limited to submicron particles, but also occurs to micrometer-sized particles in solutions with higher surfactant concentrations. These findings open up a novel avenue for controllable acoustic manipulation.

[The study of the expression of TCR BV CDR3 family in fulminant hepatitis B patients].

OBJECTIVE: To study the expression of TCR BV CDR3 family in fulminant hepatitis B (FHB) patients. METHODS: Totally 28 patients with fulminant hepatitis B (FHB) (FHB group), who were treated in our hospital from Oct. 2010. to Mar. 2012, and 20 healthy controls( HC group) were included in the study. PBMCs were isolated from anticogulated blood, and RT-PCR was used to detect the levels of TCR BV CDR3 family in the 2 groups. RESULTS: The levels of DeltaCt1, DeltaCt12 and DeltaCt20 in FHB group were higher than those in HC group (P < 0.05); The levels of DeltaCt5, DeltaCt7, DeltaCt13, DeltaCt14, DeltaCt15, DeltaCt22, DeltaCt23 in FHB group were lower than those in HC group (P < 0.05). CONCLUSIONS: The result indicates that cellular immunology is involved in the pathogenesis of the liver inflammation process of FHB.