High-throughput and directed microparticle manipulation in complex-shaped maze chambers based on travelling surface acoustic waves.

High-throughput automated manipulation of microparticles in complex-shaped environments has been demonstrated with great potential in the field of pharmaceutical microfluidics. Generally, the development of a highly efficient actuation method for functional microparticle manipulation in complex-shaped chamber structures is the key challenge of this technology. Here, we present a novel traveling surface acoustic wave (TSAW)-based manipulation device that allows for automated and high-throughput maze-solving manipulation of microparticles inside complex round-shaped and square-shaped maze chambers. This technology relies on the localized acoustic streaming effects generated by TSAWs, which are capable of automatically trapping microparticles and driving them to move along the determined trajectories based on the topographic features of the maze chamber. Numerical modelling and simulation were conducted to demonstrate the feasibility of our proposed device for targeted microparticle transportation in complex-shaped maze chamber environments. In addition, by configuring the excitation of electric signals of interdigital transducers (IDTs), such as excitation frequency and input voltage, the motion velocity of microparticles can be rapidly adjusted within 0.1 s. Thus, our device enables low-cost, compact, and contactless trajectory manipulation of high-throughput microparticles inside chambers with complex topographical features and would have application in cell-directed transportation, low-volume chemical mixing, and precise drug delivery.

Programmable motion control and trajectory manipulation of microparticles through tri-directional symmetrical acoustic tweezers.

Acoustic tweezers based on travelling surface acoustic waves (TSAWs) have the potential for contactless trajectory manipulation and motion-parameter regulation of microparticles in biological and microfluidic applications. Here, we present a novel design of a tri-directional symmetrical acoustic tweezers device that enables the precise manipulation of linear, clockwise, and anticlockwise trajectories of microparticles. By switching the excitation combinations of interdigital electrodes (IDTs), various shape patterns of acoustic pressure fields can be formed to capture and steer microparticles accurately according to pre-defined trajectories. Numerical simulations and experimental tests were conducted in this study. By adjusting the input electric signals and the fluid's viscosity, the device is able to manipulate microparticles of various forms as well as brine shrimp egg cells with the accurate modulation of motion parameters. The results show that the proposed programmable design possesses low-cost, compact, non-contact, and high biocompatibility benefits, with the capacity to accurately manage microparticles in a range of motion trajectories, independent of their physical and/or chemical characteristics. Thus, our design has strong potential applications in chemical composition analysis, drug delivery, and cell assembly.

Antimicrobial and antioxidant activities of Cortex Magnoliae Officinalis and some other medicinal plants commonly used in South-East Asia.

BACKGROUND: Eight medicinal plants were tested for their antimicrobial and antioxidant activities. Different extraction methods were also tested for their effects on the bioactivities of the medicinal plants. METHODS: Eight plants, namely Herba Polygonis Hydropiperis (Laliaocao), Folium Murraya Koenigii (Jialiye), Rhizoma Arachis Hypogea (Huashenggen), Herba Houttuyniae (Yuxingcao), Epipremnum pinnatum (Pashulong), Rhizoma Typhonium Flagelliforme (Laoshuyu), Cortex Magnoliae Officinalis (Houpo) and Rhizoma Imperatae (Baimaogen) were investigated for their potential antimicrobial and antioxidant properties. RESULTS: Extracts of Cortex Magnoliae Officinalis had the strongest activities against M. Smegmatis, C. albicans, B. subtilis and S. aureus. Boiled extracts of Cortex Magnoliae Officinalis, Folium Murraya Koenigii, Herba Polygonis Hydropiperis and Herba Houttuyniae demonstrated greater antioxidant activities than other tested medicinal plants. CONCLUSION: Among the eight tested medicinal plants, Cortex Magnoliae Officinalis showed the highest antimicrobial and antioxidant activities. Different methods of extraction yield different spectra of bioactivities.