Ultrasound-Based Scaffold-Free Core-Shell Multicellular Tumor Spheroid Formation

Abstract

In cancer research and drug screening, multicellular tumor spheroids (MCTSs) are a popular model to bridge the gap between in vitro and in vivo. However, the current techniques to culture mixed co-culture MCTSs do not mimic the structural architecture and cellular spatial distribution in solid tumors. In this study we present an acoustic trapping-based core-shell MCTSs culture method using sequential seeding of the core and shell cells into microwells coated with a protein repellent coating. Scaffold-free core-shell ovarian cancer OVCAR-8 cell line MCTSs were cultured, stained, cleared and confocally imaged on-chip. Image analysis techniques were used to quantify the shell thickness (23.2 ± 1.8 µm) and shell coverage percentage (91.2 ± 2.8%). We also show that the shell thickness was evenly distributed over the MCTS cores with the exception of being slightly thinner close to the microwell bottom. This scaffold-free core-shell MCTSs formation technique and the analysis tools presented herein could be used as an internal migration assay within the MCTS or to form core-shell MCTS co-cultures to study therapy response or the interaction between tumor and stromal cells.

Single cell organization and cell cycle characterization of DNA stained multicellular tumor spheroids

“…The ultrasonic standing wave (USW) MCTS culture platform consist of a silicon-glass multiwell chip and a transducer fitted with chip clamping equipment which has previously been described in detail 37 – 39 . In short, the multiwell chip (Fig.…”

Ultrasound-Responsive Systems as Components for Smart Materials

“…It is also possible to align and assemble different cell types into functioning cell aggregates and simple organoid-like structures. These acoustic bioassemblies are promising for biomedical research, including drug screening, 59 tissue engineering, 60,61 and disease modeling. 62 Acoustic assembly techniques complement other techniques that have also been developed for these purposes, and they generally offer advantages for assembly in certain circum- stances.…”

“…It is also possible to align and assemble different cell types into functioning cell aggregates and simple organoid-like structures. These acoustic bioassemblies are promising for biomedical research, including drug screening, tissue engineering, , and disease modeling …”

Numerical study of acoustic cell trapping above elastic membrane disks driven in higher-harmonic modes by thin-film transducers with patterned electrodes

“…Particle trapping is a central problem in the field studied by many groups. Examples are microparticle trapping in acoustic tweezers [39][40][41][42][43][44] and in disposable capillary tubes [28,45], nanoparticle by using seed particles [46][47][48], and short and long term trapping [49,50]. Trapping and the associated focusing has been created by various methods, including standing bulk [51,52], traveling bulk [53], and surface [38,54,55] acoustic waves.…”

“…Trapping and the associated focusing has been created by various methods, including standing bulk [51,52], traveling bulk [53], and surface [38,54,55] acoustic waves. An important focus area in the field is the trapping and focusing of biological cells in general [50,[56][57][58] and of circulating tumor cells in particular [30,59,60], in some cases accomplished by tuning the acoustic properties of the suspension medium tune relative to those of the given cells [30,61].…”