Vibration Induced Flow Facilitating Affinity-Based Aggregation for Rapid Detection and Quantification of Nanoparticles

The detection of bioactive nanoparticles (NPs) plays an important role in the medical and diagnostic fields. Conventional techniques for the sensitive detection of target NPs must overcome challenges such as long processing time, complex sample preparation, and high cost. Here, we show that vibration-induced flow (VIF), in which a local flow is induced around microscopic objects by applying small periodic vibrations, can be used to realize rapid, facile, highly sensitive, and low-cost detection of NPs in a minute sample. In the proposed system, the presence of NPs in a sample is detected by the formation of aggregates of affinity capture beads stirred by the VIF within a short time (approximately 15 min). Furthermore, the concentration of NPs can be quantified using the average area of the aggregate observed in bright-field microscopic images without using an expensive image analyzer and fluorescence labeling of targets, which are commonly used in other NP detection protocols. Finally, we demonstrate the detection of extracellular vesicles (EVs) to validate the applicability of the proposed system in diagnostic applications

Gut-liver interaction study on an all-polydimethylsiloxane microfluidic device integrating intestinal paracellular permeability assay

Microphysiological systems (MPSs) have attracted increasing attention as a method for simulating in vitro drug efficiency. In particular, the interaction between liver and intestine tissues is one of the primary targets since they are closely involved in drug absorption and metabolism. However, most of the intestine-liver MPSs reported previously require pumps, electrodes, and porous membranes for co-culture of cells and evaluation of intestinal permeability (i.e., Trans-Epithelial Electrical Resistance, TEER), requiring complex manufacturing processes and operations. In this study, we report an all-polydimethylsiloxane (PDMS) co-culture microfluidic device, connecting microchamber-based paracellular transport assay on gut microtissues to liver tissues matured on the same device. On one side of the device, HepaRG cells are confined within thin parallel grooves that induce their differentiation into hepatocytes. The other side of the device is connected with microchannels to the liver side and includes the gut tissues, organized above microchambers. Such microchambers allow the evaluation of paracellular permeability by fluorescence imaging. Thanks to the microfluidic device we investigated changes in intestinal permeability induced by differentiated hepatocyte excretion and found that Caco-2 permeability was decreased when co-culture with HepaRG. Due to its simplicity and straightforward implementation, this method is anticipated as an innovative and efficient approach to assess tissue barrier function in multi-organ on-chip experiments

Monolithic co-culture system for the gut-liver interaction study integrating paracellular barrier function assay

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