Sonoprinting liposomes on tumor spheroids by microbubbles and ultrasound

Abstract

Ultrasound-triggered drug-loaded microbubbles have great potential for drug delivery due to their ability to locally release drugs and simultaneously enhance their delivery into the target tissue. We have recently shown that upon applying ultrasound, nanoparticle-loaded microbubbles can deposit nanoparticles onto cells grown in 2D monolayers, through a process that we termed "sonoprinting". However, the rigid surfaces on which cell monolayers are typically growing might be a source of acoustic reflections and aspherical microbubble oscillations, which can influence microbubble-cell interactions. In the present study, we aim to reveal whether sonoprinting can also occur in more complex and physiologically relevant tissues, by using free-floating 3D tumor spheroids as a tissue model. We show that both monospheroids (consisting of tumor cells alone) and cospheroids (consisting of tumor cells and fibroblasts, which produce an extracellular matrix) can be sonoprinted. Using doxorubicin-liposome-loaded microbubbles, we show that sonoprinting allows to deposit large amounts of doxorubicin-containing liposomes to the outer cell layers of the spheroids, followed by doxorubicin release into the deeper layers of the spheroids, resulting in a significant reduction in cell viability. Sonoprinting may become an attractive approach to deposit drug patches at the surface of tissues, thereby promoting the delivery of drugs into target tissues.

Ultrasound-triggered therapeutic microbubbles enhance the efficacy of cytotoxic drugs by increasing circulation and tumor drug accumulation and limiting bioavailability and toxicity in normal tissues

“…Roovers et al . sectioned spheroids incubated with drug-loaded MBs and exposed to US and found that lipids from the liposomes were 'sonoprinted' onto the surface of the spheroids following which drug release into deeper regions was measured 82 . Recently published work from our group showed a delay in drug uptake in spheroids using drug-loaded MBs compared to free drug co-delivered with microbubbles 83 suggesting that the attached liposomes were intact following US-mediated MB destruction and prior to cellular uptake.…”

Optimization of microbubble enhancement of hyperthermia for cancer therapy in an in vivo breast tumour model

“…The study showed that prolonged ultrasound pulses and increased ultrasound exposure led to greater particle penetration [26]. Additionally, doxorubicin-liposome-loaded USMB has shown to internalized deeper into the layers of the 3D tumour spheroid thereby reducing the number of viable tumour cells [27]. Thus, the implementation of USMB in 3D tumour spheroids holds great promise to improve the delivery of chemotherapeutics agents that may have the potential for successfully treating various clinical diseases in the future.…”

Sonoporation Using Nanoparticle-Loaded Microbubbles Increases Cellular Uptake of Nanoparticles Compared to Co-Incubation of Nanoparticles and Microbubbles

“…In recent years, various forms of custom-made microbubbles have been developed for therapeutic purposes [ 1 , 3 ]. Loading the therapeutic agent onto the microbubbles has resulted in more efficient delivery both in vivo [ 31 , 32 ] and in vitro to cells and spheroids [ 33 , 34 , 35 , 36 ], especially for larger therapeutics such as drug-loaded nanoparticles. Recently, the underlying mechanism was suggested to be a phenomenon called sonoprinting, where the nanoparticles are deposited in patches on the cell membrane before being internalized [ 33 , 34 , 35 ].…”

“…Loading the therapeutic agent onto the microbubbles has resulted in more efficient delivery both in vivo [ 31 , 32 ] and in vitro to cells and spheroids [ 33 , 34 , 35 , 36 ], especially for larger therapeutics such as drug-loaded nanoparticles. Recently, the underlying mechanism was suggested to be a phenomenon called sonoprinting, where the nanoparticles are deposited in patches on the cell membrane before being internalized [ 33 , 34 , 35 ]. Such an approach allows for controlled delivery in a spatiotemporal manner and is especially promising for drugs that benefit from encapsulation in nanocarriers due to reduced premature degradation, increased solubility, improved pharmacokinetics and biodistribution, targeted delivery and reduced toxicity, increased cellular uptake and prolonged release properties.…”