Microfluidic Flow Cell Array for Controlled Cell Deposition in Engineered Musculoskeletal Tissues.

Musculoskeletal tissues contain critical gradients in extracellular matrix (ECM) composition and cell types that allow for proper mechanical function of tissues and integration between adjacent tissues. However, properly controlling these patterns in engineered tissues is difficult and tissue engineering (TE) is presently in need of methods to generate integration zones for tissue anchoring, transition zones between tissues, and controlled ECM gradients for proper mechanical function. In this study, we present a novel method of using a microfluidic flow cell array (MFCA) to precisely control cell deposition onto TE constructs to produce tunable cell patterns on engineered constructs. In this study, we characterized MFCA cell deposition to efficiently and reliably deposit cells in controllable patterns and densities. We developed methods for deposition of human adipose-derived stem cells and human osteoblasts using a 12-channel pilot printhead. We mimicked key gradients and transitions by creating two-cell and three-cell-type transitions characteristic of the integration zones of musculoskeletal tissues. Overall, we demonstrate the ability to precisely and reproducibly control cell deposition on engineered constructs using this method and control cell population gradients. We establish the production of multicell transitions and multicell interfaces utilizing MFCA cell deposition, to demonstrate the potential of the method to create an extensive variety of engineered musculoskeletal tissues. Furthermore, customization of the printhead design can accommodate various structures, sizes, shapes, and number of flow cell channels to meet specific requirements for a broad range of musculoskeletal tissues.