Foreword

The domestication of independently living cells to serve human needs is a major goal of biotechnology. Over millions of years of evolution, cells from archaeal, bacterial, and eukaryotic origin have evolved sophisticated capabilities that, if harnessed, could advance the treatment of human disease, produce carbon neutral fuels, and detect environmental agents of risk to human health. Already, cultured cells have been integrated into high-scale production systems for biotherapeutics. They are the workhorses of high-throughput assays that search for new drug leads. Much excitement surrounds the prospect of using human cells themselves as therapeutic agents, particularly stem cells with their potential to replace damaged or defective counterparts in human patients. Cells are uniquely capable of transforming simple molecular inputs, such as sugars, amino acids, and lipids, into complex biopolymers or fuel-related compounds with high efficiency. Accordingly, harnessing cells as intermediates in the conversion of solar energy to combustible compounds is a major goal of the biofuels industry. And cells have proven to be highly sensitive biosensors of pathogens and toxins. They are naturally endowed with receptors that recognize analytes and trigger auto-amplifying signaling events. These capabilities have stimulated much interest in the use of cells as components of clinical and environmental biosensing devices.

Central to realizing the goal of cell domestication is the necessity of controlling interactions of the cell with its surrounding, be it a synthetic matrix or tissue microenvironment. The cell surface, a complex landscape comprising membrane lipids, proteins, and polysaccharides, is the key translator of information between the cell’s outside and inside worlds. Cell surface components make direct contacts with the surrounding matrix allowing cells to attach and respond to their setting. Some of these interactions trigger cell responses that are critical for tissue integration or biomolecule production. At the same time, cell surface molecules comprise a dynamic data set that reports on the cell’s physiology; decoding cell surface information can reveal underlying disease states, such as cancer, viral infection, and immune activation. There is clearly a bidirectional flow of information across the cell surface, where the cell is influenced by interactions with its matrix and, reciprocally, the cell can affect its neighbors through surface contacts.

The ability to control the physical and biochemical properties of the cell surface, therefore, has powerful implications. Engineering the presentation of specific ligands on cells can direct their attachment or response to a particular matrix structure, for example, or engender new functions not possessed by native cells. Some cell surface engineering challenges can be met using conventional tools of molecular biology and genetic engineering. However, modern developments from the physical sciences—bioconjugate chemistry, lipid biophysics, polymer science, nanomaterials, and microfabrication, in particular—have created exciting new avenues for engineering cell surface properties far outside the realm of natural biology.

This book outlines the challenges and opportunities inherent to the emerging discipline of cell surface engineering and provides a detailed view of state-of-the-art methods to modulate cell surface architecture. The book concludes with the status of engineered cells in the commercial sector and previews challenges that lie ahead as cell surface engineering techniques converge with clinical efforts. A theme that pervades this book is the critical role of interdisciplinary science in achieving cell domestication. Success has involved integration of concepts and techniques from cell biology, chemistry, physics, materials science, and nanoscience. Likewise, the book will appeal to and inspire scientists and engineers from many disciplinary backgrounds. I anticipate that this book will catalyze new conversations across the aisles of the life and physical sciences, within industry and academia. It is a must-have for the bookshelves of seasoned practitioners of cell surface engineering as well as those newly learning about this exciting area of much future opportunity.