2024 AIChE Annual Meeting
Ultrasound-Responsive Phospholipid-Coated Microbubbles for Controlled Drug Delivery across Mucosa
Precise and targeted drug delivery is a major area of interest in the field of biomedical engineering. A popular approach to this goal is ultrasound-responsive materials which have shown to increase the precision and targeting in drug delivery across the skin. However, many areas of the body have a mucosal layer that impedes the effectiveness of passive drug diffusion. This includes areas such as the stomach, intestines, and bladder that have great potential as drug delivery sites for the ability to by-pass first pass metabolism. A wide range of ultrasound responsive drug carriers have been used to mitigate these challenges from the mucosal layer by enhancing passive diffusion. Microbubbles have been highly effective as a drug delivery vehicle due to the adaptability of their coatings. Phospholipid-coated microbubbles increase the stability and lend amphiphilic properties to the drug carrier. Our focus is to develop a proof of concept for an ultrasound-responsive phospholipid-coated microbubble drug carrier for a new drug of interest. In order to accomplish this, we imaged the phospholipid-coated microbubbles through microscopy to characterize their response to ultrasound waves. To achieve the best enhancement in passive diffusion we wanted to observe both acoustic streaming and cavitation. Electricity was run through a piezoelectric device (PZT) at different frequencies and the microbubble behavior was recorded over a period of three seconds. From these results, we were able to conclude that 217 KHz was the resonant frequency of the device leading to the highest amount of acoustic streaming, measured by the mass flux value. However, no cavitation was observed from the imaging. We hypothesize that this was caused by the additional stability added by the phospholipid layer on the microbubbles. Therefore, a different microbubble coating would be better suited for the desired ultrasound response behavior. This further research will hopefully advance ultrasound responsive drug delivery devices for faster, controlled drug release in order to increase patient comfort and compliance.