Rapid retraction of microvolume aqueous plugs traveling in a wettable capillary

Abstract

We report a transport behavior-specifically, rapid retraction movement-of small (∼L) deionized water plugs traveling in series within a small wettable tubular geometry. In this study, two water plugs separated by a certain distance in a dry cylindrical glass capillary were moved by positive pressure airflow applied at the tube inlet. As the plugs travel, a thin aqueous film is generated between the plugs as a result of the leading plug's aqueous deposition onto the inner surface of the tube. The leading plug continuously loses volume by film deposition onto the surface and eventually ruptures. Then, the lagging plug quickly travels the distance initially separating the two plugs (plug retraction). Our studies show that the rapid retraction of the lagging plug is caused by surface tension in addition to the positive pressure applied. Furthermore, the plug retraction speed is strongly affected by tube radius and the distance between the plugs.

Controlled delivery and minimally invasive imaging of stem cells in the lung

“…Then, the plug is pushed along the airway toward the target region by applying positive air pressure to the liquid plug by ventilating the lung. As the liquid plug travels, a thin film is deposited on the airway surface 30,31 , enabling cell attachment to the airway. The cell delivery process is complete when the decreasing volumes of all liquid plugs are finally exhausted due to film deposition (Fig.…”

“…Because cells are seeded by liquid film generated, cell density at the surfaces (i.e., cell-seeding density) can be manipulated with the plug capillary number. For example, because the thickness of the liquid film is proportional to the traveling speed of the plug 30,31 , a greater number of cells can be trapped and deposited on the airways by a plug traveling faster. Similarly, cell-seeding density can increase with cell concentration within the liquid plug.…”

The Cellular and Physiological Basis for Lung Repair and Regeneration: Past, Present, and Future

“…For extracorporeal lungs, cross-circulation was used to extend the duration of lung maintenance ex vivo from hours to days, by providing metabolic clearance and systemic factors to the perfused and ventilated lung (Figure 4; O'Neill et al, 2017). This method allowed time for multiscale therapeutic interventions, with the aid of real-time theranostic (therapeutic + diagnostic) imaging (Kim et al, 2015b(Kim et al, , 2017. By the end of cross-circulation support, the lungs that were severely damaged by ischemia or gastric aspiration exceeded transplantation criteria, and the recipients tolerated the procedure without significant changes in physiologic parameters.…”

Imaging-Guided Bioreactor for De-Epithelialization and Long-Term Cultivation ofEx VivoRat Trachea

“…Instillation of a small volume of liquid (e.g., aqueous solution) through the respiratory tract can generate a thin layer of the liquid onto the airway lumen. [49][50][51] Following disruption of the epithelium through detergent exposure, the lysed cells were then cleared from the trachea by washing with PBS buffer while the entire trachea was vibrated mechanically using our custom-built shaker (Fig. S1).…”

“…Specifically, a small volume (50 μL) of either 2% or 4% SDS solution was infused through the trachea using a programmable syringe pump (flow rate: 6.3 mL.s -1 ; AL-4000, World Precision Instruments) to generate a thin film of the detergent solution on the luminal surface of the trachea. 49,51 To promote de-epithelization, the trachea was incubated in the bioreactor for 20 min at 37°C. The bioreactor was then mechanically vibrated using our custom-built shaker at 20 Hz of frequency while being washed with 1´ PBS solution three times (volume: 500 µL; flow rate: 10 mL.s -1 ).…”