Biointerface science, defined as the study and control of biomolecular interactions at surfaces, is a critical component of many aspects of biotechnology, but it has only recently begun to attract the attention it deserves as a unique interdisciplinary research area. This issue of MRS Bulletin explores the rich diversity of function provided by biomolecules at interfaces and the unparalleled opportunities for applications, which range from clinical diagnostics, biomaterials, and tissue engineering to genomics and proteomics. This diversity will continue to drive the evolution of biointerface science.

The development of dynamic substrates that can modulate the behavior of adherent cells is important for fundamental studies in cell biology, applications in biomaterials, and engineering microsystems that combine cellular and material components. This review outlines several strategies based on physical transduction schemes (including electrical, photochemical, thermal, and mechanical forces) for designing interfaces that are active and can signal changes in the behavior of attached cells.

Recent progress in various biotechnology fields, such as microfluidics, tissue engineering, and cellular biology, has created a great demand for substrates that can undergo defined remodeling with time. As a result, the latest research on materials with dynamically controllable surface properties has led to a variety of novel smart surface designs.

The possibility of recreating various tissues and organs for the purpose of regenerative medicine has received much interest. However, the field of tissue engineering has been restricted by the limitations of conventional approaches. A method to circumvent the need for traditional scaffold-based technologies is cell-sheet engineering, which uses temperature-responsive culture dishes. These surfaces, which are created by grafting the temperature-responsive polymer poly(N-isopropylacrylamide) onto ordinary culture dishes, enable the non-invasive harvesting of cells as intact sheets by simple temperature reduction. This article reviews current research on the applications of cell-sheet engineering for the reconstruction of various tissues, as well as the intelligent surfaces used by this novel technology.

Assays based on observations of the biological responses of individual cells to their environment have the potential to make enormous contributions to cell biology and biomedicine.To carry out well-defined experiments using cells, both the environments in which the cells live and the cells themselves must be well defined. Cell-based assays are now plagued by inconsistencies and irreproducibility, and a primary challenge in the development of informative assays is to understand the fundamental bases for these inconsistencies and to limit them. It now seems that multiple factors may contribute to the variability in the response of individual cells to stimuli; some of these factors may be extrinsic to the cells, some intrinsic. New techniques based on microengineering—especially using soft lithography to pattern surfaces at the molecular level and to fabricate microfluidic systems—have provided new capabilities to address the extrinsic factors. This review discusses recent advances in materials science that provide well-defined physical environments that can be used to study cells, both individually and in groups, in attached culture. It also reviews the challenges that must be addressed in order to make cell-based assays reproducible.

Recently, a variety of patterning techniques have reached feature sizes of 100 nm or less, a size range very relevant to biology. Proteins, vesicles, and macromolecular assemblies can now be handled and specifically placed onto predefined artificial patterns, triggering defined functions in cells and revealing the details of cell–surface interactions. Simultaneously, novel surface chemistries have been developed that are able to induce specific bioresponses (e.g., mimicking the features of the extracellular matrix) and at the same time suppress the nonspecific effects of complex biological solutions. This article reviews the basic principles and properties of multifunctional physisorbed monolayers that can be used in combination with nanopatterning techniques to create biologically relevant surface features. Furthermore, selected examples of nanopatterns created by novel combinations of different top-down and bottom-up approaches are presented, including systems with specific bioligands, proteins, vesicles, and cells.

The function of biologically important ion channels can be measured in supported lipid membranes by impedance spectroscopy. This approach offers substantial advantages over traditional electrophysiological measurements. In this article, we present an overview of the field, with a special emphasis on the reconstitution of ion channels in lipid bilayers tethered to gold electrodes and the modulation of their channel activity by specific ligand binding.