Functional three‐dimensional HepG2 aggregate cultures generated from an ultrasound trap: Comparison with HepG2 spheroids

Abstract

Three-dimensional culture systems are an ideal in vitro model being capable of sustaining cell functionalities in a manner that resembles the in vivo conditions. In the present study, we developed an ultrasound trap-based technique to rapidly produce HepG2 hepatocarcinoma cell aggregates within 30 min. Enhanced junctional F-actin was observed at the points of cell-cell contact throughout the aggregates. HepG2 aggregates prepared by the ultrasound trap can be maintained in culture on a P-HEMA-coated surface for up to 3 weeks. The cells in these aggregates proliferated during the initial 3 days and cell number was consistent during the following maintenance period. Albumin secretion from these HepG2 aggregates recovered after 3 days of aggregate formation and remained relatively stable for the following 12 days. Cytochrome P450-1A1 activity was significantly enhanced after 6 days with maximal enzyme activity observed between 9 and 18 days. In addition, comparison experiments demonstrated that HepG2 aggregates generated by the ultrasound trap had comparable functional characterizations with HepG2 spheroids formed by a traditional gyrotatory-mediated method. Our results suggest that HepG2 aggregate cultures prepared through the ultrasound trap-based technique may provide a novel approach to produce in vitro models for hepatocyte functional studies.

Polymer-Based Microfluidic Devices for Pharmacy, Biology and Tissue Engineering

“…Studies have shown that acoustic trapping of biological cells does not affect the viability of the cells [194][195][196]. Acoustic trapping has been used to culture yeast cells [195], study the effect on inherent agglomeration for in vitro cell-cell interaction studies such as cell adhesion dynamics [196][197][198], long-term culturing [199], and investigation of cell viability and proliferation such as for Hep2G cultures in alginate-gel [200]. Successful acoustical trapping of microparticles has been shown in a flow chamber under environmental control, while Raman spectroscopy was used to detect, distinguish and monitor the chemical reactions in real time [201].…”

Ultrasound assisted particle and cell manipulation on-chip

“…Working without scaffolds, Liu et al [90] formed aggregates of a hepatocyte cell line within an ultrasonic trap, using the ultrasound to accelerate the aggregate formation and to modify their geometry during the initial 30 minutes of their formation. The cells were then maintained in culture in the absence of ultrasound for up to three weeks and shown to have similar functional characteristics to hepatocyte spheroids prepared using gyrotation culture techniques.…”

Roles of Spheroid Formation of Hepatocytes in Liver Tissue Engineering

“…External forces such as dielectrophoresis (35), magnetic fields (36) and ultrasound trap (37,38) were used to enhance cell aggregation and spheroid formation from single cells although specialized equipment is necessary in spheroid formation of the cells. Spheroid formation of HepG2 adhered on a PHEMA-coated surface and encapsulated in alginate capsules was formed within 30 and 5 min, respectively, by the ultrasound trap with good liver-specific functions (37).…”

“…Spheroid formation of HepG2 adhered on a PHEMA-coated surface and encapsulated in alginate capsules was formed within 30 and 5 min, respectively, by the ultrasound trap with good liver-specific functions (37).…”