We present a programmable acoustofluidic pump that utilizes the acoustic streaming effects generated by the oscillation of tilted sharp-edge structures. This sharp-edge based acoustofluidic pump is capable of generating stable flow rates as high as 8 μL/min (~76 Pa of pumping pressure), and it can tune flow rates across a wide range (nL/min to μL/min). Along with its ability to reliably produce stable and tunable flow rates, the acoustofluidic pump is easy to operate and requires minimum hardware, showing great potential for a variety of applications.

We demonstrate the first microfluidic-based on-chip liquefaction device for human sputum samples. Our device is based on an acoustofluidic micromixer using oscillating sharp edges. This acoustofluidic sputum liquefier can effectively and uniformly liquefy sputum samples at a throughput of 30 μL min(-1). Cell viability and integrity are maintained during the sputum liquefaction process. Our acoustofluidic sputum liquefier can be conveniently integrated with other microfluidic units to enable automated on-chip sputum processing and analysis.

The effects of vitamin supplements and/or diet on the vitamin levels in milk of women were determined at 6 months postpartum. Six subjects consumed a daily supplement (Natalins, Mead-Johnson) in addition to a well-balanced diet--supplemented group, and six subjects consumed only a well-balanced diet--nonsupplemented group. The subjects expressed milk for 3 days at 4-hr intervals, 0, 4, 8, and 12 hr after awakening or taking their vitamin supplement. A 4-day diet record, fasting blood sample, and 24-hr urine samples were collected on each subject at 6 months postpartum. Nutrient intake from diet alone did not differ significantly between the two groups except for riboflavin intake which was significantly higher in the supplemented group. The nutritional status of all women indicated excellent dietary intakes, which vitamin supplementation did not alter significantly. Milk concentration of vitamin B6, vitamin B12, folate, thiamin, riboflavin, and vitamin C, did not differ significntly between groups. Thiamin, vitamin B12, and vitamin B6 concentration in the milk did appear to plateau during the day. Vitamin supplementatin at 6 months postpartum did not affect the breast milk concentration or the nutritional status of well-nourished women.

The ability to generate stable, spatiotemporally controllable concentration gradients is critical for resolving the dynamics of cellular response to a chemical microenvironment. Here we demonstrate an acoustofluidic gradient generator based on acoustically oscillating sharp-edge structures, which facilitates in a step-wise fashion the rapid mixing of fluids to generate tunable, dynamic chemical gradients. By controlling the driving voltage of a piezoelectric transducer, we demonstrated that the chemical gradient profiles can be conveniently altered (spatially controllable). By adjusting the actuation time of the piezoelectric transducer, moreover, we generated pulsatile chemical gradients (temporally controllable). With these two characteristics combined, we have developed a spatiotemporally controllable gradient generator. The applicability and biocompatibility of our acoustofluidic gradient generator are validated by demonstrating the migration of human dermal microvascular endothelial cells (HMVEC-d) in response to a generated vascular endothelial growth factor (VEGF) gradient, and by preserving the viability of HMVEC-d cells after long-term exposure to an acoustic field. Our device features advantages such as simple fabrication and operation, compact and biocompatible device, and generation of spatiotemporally tunable gradients.

Whether vitamin A (VA) has a role in the development of metabolic abnormalities associated with intake of a high-fat diet (HFD) is unclear. Sprague–Dawley rats after weaning were fed an isocaloric VA sufficient HFD (VAS-HFD) or a VA deficient HFD (VAD-HFD) for 8 weeks. Body mass, food intake, liver and adipose tissue mass, and the hepatic expression levels of key proteins for metabolism were determined. VAD-HFD rats had lower body, liver, and epididymal fat mass than VAS-HFD rats. VAD-HFD rats had lower hepatic protein expression levels of cytochrome P450 26A1, glucokinase, and phosphoenolpyruvate carboxykinase than VAS-HFD rats. VAD-HFD rats had higher protein levels of glycogen synthase kinase (GSK)-3α and lower levels of GSK-3β, but not glycogen synthase, than VAS-HFD rats. VAD-HFD rats had higher hepatic levels of insulin receptor substrate-1 (IRS-1), insulin receptor β-subunit, mitogen-activated protein kinase proteins, and peroxisome proliferator-activated receptor-gamma coactivator 1α mRNA, and lower level of IRS-2 protein than VAS-HFD rats. These results indicate that in a HFD setting, VA deficiency attenuated HFD-induced obesity, and VA status altered the expression levels of proteins required for glucose metabolism and insulin signaling. We conclude that VA status contributes to the regulation of hepatic glucose and lipid metabolism in a HFD setting, and may regulate hepatic carbohydrate metabolism.