Poster Title

Microbubble-Induced Aggregation of Red Blood Cells

Grade Level at Time of Presentation

Junior

Major

Biology BS (Cellular Physiology) and Chemistry BA

Minor

none

Institution

University of Louisville

KY House District #

98

KY Senate District #

18

Department

Department of Biology

Abstract

Each year, millions of people around the world are not able to receive life-saving blood transfusions because blood requires constant refrigeration and expires after only 42 days. Biologists have known for decades that a simple sugar called trehalose can preserving animals and their cells in a dried state, allowing them to be stored at room temperature for years and be revived by simply adding water. Trehalose must be present on both sides of the cell boundaries (membranes) to offer protection, and transporting trehalose across human cell membranes is challenging. Sonoporation, is a process wherein ultrasound waves induce small gas bubbles to expand and contract (cavitation) and we discovered that this technique is a promising method for carrying trehalose across the cell membrane into red blood cells (RBCs). However, some microbubbles can be toxic and cause RBCs to aggregate in solutions containing low concentrations of ions. Unfortunately, low ion concentrations are desired during processing for dry storage of RBCs. To solve the toxicity challenge, different concentrations of RBCs were exposed to a variety of microbubble dosages under different conditions in solution. RBC aggregation was observed under any conditions tested when the RBCs were exposed to standard microbubbles in a low-salt solution, whereas aggregation was never observed in a high-salt solution. The observed toxicity could be correlated with the overall charge of the microbubbles (‘zeta potential’). It was found that standard microbubbles had a zeta potential of +31 mV. Changing the microbubble composition and their zeta potential to +21 mV allowed for sonoporation in low-salt solution without causing aggregation or other toxic side effects of high-salt concentrations. Further optimization of the sonoporation method may result in a freeze-dried transfusion unit that is stable at room temperature and could save millions of lives around the globe. (Supported by NSF-PFI-1827521 and UofL SROP-2019).

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Microbubble-Induced Aggregation of Red Blood Cells

Each year, millions of people around the world are not able to receive life-saving blood transfusions because blood requires constant refrigeration and expires after only 42 days. Biologists have known for decades that a simple sugar called trehalose can preserving animals and their cells in a dried state, allowing them to be stored at room temperature for years and be revived by simply adding water. Trehalose must be present on both sides of the cell boundaries (membranes) to offer protection, and transporting trehalose across human cell membranes is challenging. Sonoporation, is a process wherein ultrasound waves induce small gas bubbles to expand and contract (cavitation) and we discovered that this technique is a promising method for carrying trehalose across the cell membrane into red blood cells (RBCs). However, some microbubbles can be toxic and cause RBCs to aggregate in solutions containing low concentrations of ions. Unfortunately, low ion concentrations are desired during processing for dry storage of RBCs. To solve the toxicity challenge, different concentrations of RBCs were exposed to a variety of microbubble dosages under different conditions in solution. RBC aggregation was observed under any conditions tested when the RBCs were exposed to standard microbubbles in a low-salt solution, whereas aggregation was never observed in a high-salt solution. The observed toxicity could be correlated with the overall charge of the microbubbles (‘zeta potential’). It was found that standard microbubbles had a zeta potential of +31 mV. Changing the microbubble composition and their zeta potential to +21 mV allowed for sonoporation in low-salt solution without causing aggregation or other toxic side effects of high-salt concentrations. Further optimization of the sonoporation method may result in a freeze-dried transfusion unit that is stable at room temperature and could save millions of lives around the globe. (Supported by NSF-PFI-1827521 and UofL SROP-2019).