Alginate-Zein Microcarriers with Tunable Stiffness: Fabrication and Application in 3D Osteosarcoma Modeling

Engineering of microcarriers with tailored properties is a pivotal challenge in developing physiologically relevant three-dimensional (3D) in vitro tumor models, which are emerging as critical tools in cancer research. This study developed alginate-zein (AZ) composite microcarriers with tuned mechanical properties via a tailored microfluidic device for constructing in vitro 3D osteosarcoma models. A co-axial capillary microfluidic device was prepared to generate AZ microcarriers, and the ratio of calcium alginate to zein was varied. MG-63 were cultured on the microcarriers to obtain proposed osteosarcoma models. Intracellular reactive oxygen species (ROS) levels of these cells were quantified, and qRT-PCR analysis was conducted to examine the expression of genes associated with proliferation, apoptosis, migration, and invasion, along with other promalignancy markers. Doxorubicin was used to validate the utility of this model for drug screening. It was shown that AZ microcarriers were of high uniformity and monodispersity. Cell-microcarrier constructs were formed after MG-63 being cultured on these microcarriers, which further exhibited upregulated intracellular ROS levels and elevated expression of vegf, vim, cdh-2 (n-cadherin), and runx2, alongside downregulated cdh-1 (e-cadherin) expression. The expression of these promalignant markers and observed enhancement in drug resistance by cells within the constructs demonstrated the successful establishment of the expected osteosarcoma model and its application for drug screening. AZ-β microcarriers with a relative zein portion of 9:1 and an elastic modulus of 159.73 kPa were the optimal microcarrier for establishing the osteosarcoma model. This study presented a robust methodology for establishing 3D in vitro tumor models for developing therapeutic intervention.