Monocyte-based microrobot with chemotactic motility for tumor theragnosis

ABSTRACT Biocompatibility, sensing, and self‐actuation are very important features for a therapeutic biomedical microrobot. As a new concept for tumor theragnosis, this paper proposes a monocyte‐based microrobots, which are combining the phagocytosis and engulfment activities containing human acute monocytic leukemia cell line (THP‐1) with various sized polystyrene microbeads are engulfed instead of a therapeutic drug. For the validation of the blood vessel barrier‐penetrating activity of the monocyte‐based microrobot, we fabricate a new cell migration assay with monolayer‐cultured endothelial cell (HUVEC), similar with the blood vessels. We perform the penetrating chemotactic motility of the monocyte‐based microrobot using various types of the chemo‐attractants, such as monocyte chemotactic protein (MCP)‐1, human breast cancer cell lines (MCF7)‐cell lysates, and ‐contained alginate spheroids. The monocyte‐based microrobot show chemotactic transmigrating motilities similar with what an actual monocyte does. This new paradigm of a monocyte‐based microrobot having various useful properties such as biocompatibility, sensing, and self‐actuation can become the basis of a biomedical microrobot using monocytes for diagnosis and therapy of various diseases. Biotechnol. Bioeng. 2014;111: 2132–2138. © 2014 Wiley Periodicals, Inc. Validation of tumor targeting ability of a biomedical microrobot using monocyte‐based microrobot and modified cell migration chamber. (A) Development of monocyte‐based microrobot using various sized fluorescent polystyrene (PS) microbeads and monocytes. (B) Schematic representation of cell migration chamber and (C) experimental setup for validation of transmigrating ability of monocyte‐based microrobot.