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...

Despite the ubiquitous use over the past 150 years, the functions of the current medical needle are facilitated only by mechanical shear and cutting by the needle tip, i.e. the lancet. In this study, we demonstrate how nonlinear ultrasonics (NLU) extends the functionality of the medical needle far beyond its present capability. The NLU actions were found to be localized to the proximity of the needle tip, the SonoLancet, but the effects extend to several millimeters from the physical needle boundary. The observed nonlinear phenomena, transient cavitation, fluid streams, translation of micro- and nanoparticles and atomization, were quantitatively characterized. In the fine-needle biopsy application, the SonoLancet contributed to obtaining tissue cores with an increase in tissue yield by 3–6× in different tissue types compared to conventional needle biopsy technique using the same 21G needle. In conclusion, the SonoLancet could be of interest to several other medical applications, including drug or gene delivery, cell modulation, and minimally invasive surgical procedures.

Omnidirectional microscopy (OM) is an emerging technology capable of enhancing the threedimensional (3D) microscopy widely applied in life sciences. In OM, precise position and orientation control of the sample are required. However, current OM technology relies on destructive, mechanical methods to hold the samples, such as embedding samples in gel or attaching them to a needle to permit orientation control. A non-contacting alternative is to levitate the sample. Up until now levitation methods have lacked orientation control. We enable omnidirectional access to the sample by introducing a method to control acoustic levitation that provides precise orientation control. Such control around three axes of rotation permits rapid imaging of the sample from any direction with a fixed camera and subsequent 3D shape reconstruction. The control of non-spherical particles is achieved using an asymmetric acoustic field created with a phase-controlled transducer array. Our technology allows robust 3D imaging of delicate samples and their study in a time-lapse manner. We foresee that the described method is not limited to microscopy and optical imaging, but is also compatible with automated sample handling, light-sheet microscopy, wall-less chemistry, and non-contacting tomography.