There has been tremendous interest in constructing in vitro cardiac tissue for a range of fundamental studies of cardiac development and disease and as a commercial system to evaluate therapeutic drug discovery prioritization and toxicity. Although there has been progress towards studying 2-dimensional cardiac function in vitro, there remain challenging obstacles to generate rapid and efficient scaffold-free 3-dimensional multiple cell type co-culture cardiac tissue models. Herein, we develop a programmed rapid self-assembly strategy to induce specific and stable cell-cell contacts among multiple cell types found in heart tissue to generate 3D tissues through cell-surface engineering based on liposome delivery and fusion to display bio-orthogonal functional groups from cell membranes. We generate, for the first time, a scaffold free and stable self assembled 3 cell line co-culture 3D cardiac tissue model by assembling cardiomyocytes, endothelial cells and cardiac fibroblast cells via a rapid inter-cell click ligation process. We compare and analyze the function of the 3D cardiac tissue chips with 2D co-culture monolayers by assessing cardiac specific markers, electromechanical cell coupling, beating rates and evaluating drug toxicity.

Proper cell-cell contact and communication are essential for the correct development and survival of higher order organisms. In order to study complex cell interactions that occur in vivo, model systems that are able to recapitulate 3D cell-cell interactions in vitro are key to advancing new biotechnologies, therapeutics, and tissue engineering applications. Herein, we show a new strategy to rapidly and efficiently generate complex multiple cell line containing spheroids and tissues in microfluidic flow without the use of scaffolds, molecular biology, or metabolic biosynthesis. The method relies on the integration of microfluidics, liposome fusion, bio-orthogonal chemistry, and cell surface engineering to rapidly click coculture cell assemblies in flow. We demonstrate this strategy by assembling various combinations of cell types with an interfacial cell to cell click chemistry in microfluidic flow to generate a range of spheroid types and oriented tissue multilayers.

The rapid development of new small molecule drugs, nanomaterials, and genetic tools to modulate cellular function through cell surface manipulation has revolutionized the diagnosis, study, and treatment of disorders in human health. Since the cell membrane is a selective gateway barrier that serves as the first line of defense/offense and communication to its environment, new approaches that molecularly engineer or tailor cell membrane surfaces would allow for a new era in therapeutic design, therapeutic delivery, complex coculture tissue construction, and in situ imaging probe tracking technologies. In order to develop the next generation of multimodal therapies, cell behavior studies, and biotechnologies that focus on cell membrane biology, new tools that intersect the fields of chemistry, biology, and engineering are required. Herein, we develop a liposome fusion and delivery strategy to present a novel dual receptor and reporter system at cell surfaces without the use of molecular biology or metabolic biosynthesis. The cell surface receptor is based on bio-orthogonal functional groups that can conjugate a range of ligands while simultaneously reporting the conjugation through the emission of fluorescence. We demonstrate this dual receptor and reporter system by conjugating and tracking various cell surface ligands for temporal control of cell fluorescent signaling, cell-cell interaction, and tissue assembly construction.

The ability to tailor bacteria cell surfaces with non-native molecules is critical to advance the study of bacteria communication, cell behavior, and for next-generation therapeutics to improve livestock and human health. Such modifications would allow for novel control over cell behavior, cell-cell interactions, biofilm formation, adjuvant conjugation, and imaging. Current methods to engineer bacteria surfaces have made major advances but rely on complicated, slow, and often expensive molecular biology and metabolic manipulation methods with limited scope on the type of molecules installed onto the surface. In this report, we introduce a new straightforward method based on liposome fusion to engineer Gram-negative bacteria cells with bio-orthogonal groups that can subsequently be conjugated to a range of molecules (biomolecules, small molecules, probes, proteins, nucleic acids, ligands, and radiolabels) for further studies and programmed behavior of bacteria. This method is fast, efficient, inexpensive, and useful for installing a broad scope of ligands and biomolecules to Gram-negative bacteria surfaces.

There has been tremendous interest in constructing in vitro liver organ models for a range of fundamental studies of cell signaling, metabolism, and infectious diseases, and as a commercial system to evaluate therapeutic drug discovery prioritization and toxicity. Although there has been progress toward studying two-dimensional hepatic function in vitro, there remain challenging obstacles to generate rapid and efficient scaffold-free three-dimensional multiple cell line coculture tissue models of liver. Herein, we develop and employ a strategy to induce specific and stable cell-cell contacts among multiple hepatic cell lines to generate 3D tissues through cell-surface engineering based on liposome delivery and fusion to display bio-orthogonal functional groups from cell membranes. We generate, for the first time, a three cell line coculture 3D liver tissue model by assembling hepatocytes, hepatic endothelial cells, and hepatic stellate cells via a rapid intercell click ligation process. We compare and analyze the function of the superior 3D liver tissue chips with 2D coculture monolayer by assessing mitochondrial metabolic activity and evaluating drug toxicity.