Oleogels are lipid-based soft materials composed of large fractions of oil (> 85%) developed as saturated and hydrogenated fat substitutes to reduce cardiovascular diseases caused by obesity. Promising oleogels are unstable during storage, and to improve their stability careful control of the crystalline network is necessary. However, this is unattainable with state-of-the-art technologies. We employ ultrasonic standing wave (USSW) fields to modify oleogel structure. During crystallization, the growing crystals move towards the US-SW nodal planes. Homogeneous, dense bands of microcrystals form independently of oleogelator type, concentration, and cooling rate. The thickness of these bands is proportional to the USSW wavelength. These new structures act as physical barriers in reducing the migration kinetics of a liposoluble colorant compared to statically crystallized oleogels. These results may extend beyond oleogels to potentially be used wherever careful control of the crystallization process and final structure of a system is needed, such as in the cosmetics, pharmaceutical, chemical, and food industries. Abbreviations USSW Ultrasonic standing wave HIU High-intensity ultrasound Oleogels are lipid-based materials that contain 85%-99.5% liquid oil trapped in a network of structuring molecules called oleogelators 1. Oleogels were developed during the last 15 years as saturated and hydrogenated fat substitutes 2. Saturated fats are used in the food, cosmetics, and pharmaceutical industries due to their ability to form solid and crystalline structures at room temperature. These crystalline structures are employed as delivery and protective systems and structuring agents 3. However, excessive consumption of saturated fats correlates with obesity that in turn causes cardiovascular diseases, metabolic syndrome and type-2 diabetes 4-6. Obesity is a global problem. In 2014, 2.5 billion adults and 41 million children worldwide were overweight or obese; these numbers have doubled since 1980 7. The annual healthcare costs related to treating diseases caused by/related to obesity is 60 billion euros in Europe 8 and 210 billion dollars in the USA 9. Lowering the intake of saturated fats, for example, by using oleogels rich in polyunsaturated fatty acids can help reduce cardiovascular diseases caused by obesity. Oleogels can be prepared using direct 1 and indirect 10 methods. Indirect methods are foam, emulsion and solvent exchange and aerogel templating where proteins or polysaccharides are used to prepare the scaffold in which oil is absorbed/retained 10. The direct method makes use of self-assembling molecules (e.g. monoglycerides, waxes, fatty acids, fatty alcohols, ethyl cellulose, phytosterols, phytosterol esters, etc.) to gel the oil 1. Structuring agents are dispersed into the oil, and then a heating and a cooling step are successively applied. The oleogelators rearrange themselves during the cooling step to form a crystalline/polymeric network. The network entraps the oil and gels the system 11. The direct method is...

Acoustic levitation provides potential to characterize and manipulate material such as solid particles and fluid in a wall-less environment. While attempts to levitate small animals have been made, the biological effects of such levitation have been scarcely documented. Here, our goal was to explore if zebrafish embryos can be levitated (peak pressures at the pressure node and anti-node: 135 dB and 144 dB, respectively) with no effects on early development. We levitated the embryos (n = 94) at 2–14 hours post fertilization (hpf) for 1000 (n = 47) or 2000 seconds (n = 47). We compared the size and number of trunk neuromasts and otoliths in sonicated samples to controls (n = 94), and found no statistically significant differences (p > 0.05). While mortality rate was lower in the control group (22.3%) compared to that in the 1000 s (34.0%) and 2000 s (42.6%) levitation groups, the differences were statistically insignificant (p > 0.05). The results suggest that acoustic levitation for less than 2000 sec does not interfere with the development of zebrafish embryos, but may affect mortality rate. Acoustic levitation could potentially be used as a non-contacting wall-less platform for characterizing and manipulating vertebrae embryos without causing major adverse effects to their development.

Electrospinning is commonly used to produce polymeric nanofibers. Potential applications for such fibers include novel drug delivery systems, tissue engineering scaffolds, and filters. Electrospinning, however, has shortcomings such as needle clogging and limited ability to control the fiber-properties in a non-chemical manner. This study reports on an orifice-less technique that employs high-intensity focused ultrasound, i.e. ultrasound-enhanced electrospinning. Ultrasound bursts were used to generate a liquid protrusion with a Taylor cone from the surface of a polymer solution of polyethylene oxide. When the polymer was charged with a high negative voltage, nanofibers jetted off from the tip of the protrusion landed on an electrically grounded target held at a constant distance from the tip. Controlling the ultrasound characteristics permitted physical modification of the nanofiber topography at will without using supplemental chemical intervention. Possible applications of tailor-made fibers generated by ultrasound-enhanced electrospinning include pharmaceutical controlled-release applications and biomedical scaffolds with spatial gradients in fiber thickness and mechanical properties.