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We present a microfluidic technique that shrinks lipidstabilized microbubbles from O(100) to O(1) µm in diameter–the size that is desirable in applications as ultrasound contrast agents. We achieve microbubble shrinkage by utilizing vacuum channels that are adjacent to the microfluidic flow channels to extract air from the microbubbles. We tune a single parameter, the vacuum pressure, to accurately control the final microbubble size. Finally, we demonstrate that the resulting O(1) µm diameter microbubbles have similar stability to microfluidics generated microbubbles that are not exposed to vacuum shrinkage. We anticipate that, with additional scale-up, this simple approach to shrink microbubbles generated microfluidically will be desirable in ultrasound imaging and therapeutics applications.

Membraneless organelles (MLOs) formed through liquid-liquid phase separation (LLPS) are becoming increasingly relevant to understanding viral-host interactions, neurodegenerative disease, and cancer. The modulation of LLPS involves many parameters and components. To describe these modulators, typical

Bioelastomers are extensively used in biomedical applications due to their desirable mechanical strength, tunable properties, and chemical versatility; however, three-dimensional (3D) printing bioelastomers into microscale structures has proven elusive. Herein, a high throughput omnidirectional printing approach via coaxial extrusion is described that fabricates perfusable elastomeric microtubes of unprecedently small inner diameter (350-550 µm) and wall thickness (40-60 µm). The versatility of this approach is shown through the printing of two different polymeric elastomers, followed by photocrosslinking and removal of the fugitive inner phase. Designed experiments are used to tune the microtube dimensions and stiffness to match that of native ex vivo rat vasculature. This approach affords the fabrication of multiple biomimetic shapes resembling cochlea and kidney glomerulus and affords facile, high-throughput generation of perfusable structures that can be seeded with endothelial cells for biomedical applications. Post-printing laser micromachining is performed to generate micro-sized holes (520 µm) in the tube wall to tune microstructure permeability. Importantly, for organ-on-a-chip applications, the described approach takes only 3.6 min to print microtubes (without microholes) over an entire 96-well plate device, in contrast to comparable hole-free structures that take between 1.5 and 6.5 days to fabricate using a manual 3D stamping approach.

Polyelectrolyte microcapsules (PEMCs) have biocompatible microcompartments. Therefore, PEMCs are useful for applications in cosmetics, food, pharmaceutics, and other industries. The fabrication of PEMCs often involves the use of harsh chemicals or cytotoxic organic phases that make biomedical applications of the microcapsules challenging. In this report, we present an all-aqueous droplet microfluidics platform for the generation of magnetic PEMCs. In the platform, we use an aqueous-two-phase system (ATPS) of polyethylene glycol (PEG) and dextran (Dex), to generate water-in-water droplets, which are magnetically functionalized with ferrofluid. Strong polyelectrolytes (PEs) with opposite charges are used in each ATPS phase. We make emulsion templates of magnetic Dex, containing the polycations, in a continuous phase of PEG. We then apply a magnetic field to move the magnetic droplets to a second PEG phase, which contains the polyanions. By careful tuning of the fluxes of the two PEs in their respective phases, we trigger the formation of a shell at the droplet interface. Owing to the presence of the ferrofluid, the resulting microcapsules are magnetically responsive. We show that the magnetic PEMCs are capable of passive release of large pseudo-drugs as well as triggered release using external stimuli such as osmotic shock and pH change. We expect that magnetic PEMCs from this biocompatible all-aqueous platform will find utility in the fabrication of functionalized drug carriers for targeted drug delivery.

Obstructive sleep apnea (OSA) is extremely common among bariatric surgical candidates. Identifying those at risk for moderate to severe OSA is challenging. Testing all bariatric surgical candidates with a level 1 polysomnographic study is expensive and resource intensive. The aim of this study is to evaluate three standardized screening questionnaires that are utilized to identify high-risk patients for OSA undergoing bariatric surgery. A retrospective review of data collected prospectively was undertaken on bariatric surgical patients who have not had a preexisting diagnosis of OSA. Each patient was subjected to the STOP BANG and Berlin Questionnaires as well as the Epworth Sleepiness Scale (ESS), after which a level 1 polysomnogram was undertaken. Nonparametric receiver operating characteristic analyses were used to evaluate the relationship between questionnaire scores and OSA as determined by a formal sleep lab study. There were 266 patients subjected to a standard overnight polysomnogram and screening questionnaires. Area under the curve (AUC) values for analyses including the entire sample were significantly (p