Layer-by-layer assembly as a robust method to construct extracellular matrix mimic surfaces to modulate cell behavior

Cellular behavior is crucially dependent on the biophysical and biochemical properties of the extra cellular matrix (ECM), in which the properties of biochemistry, topography, and mechanics are critically important and dominantly studied. Since its introduction by Decher and Lvov in the early 1990s, layer-by-layer (LbL) assembly technology has received considerable interest for constructing polymeric thin films in both academic and industrial studies. The technology has been especially important in applications involving biomedical materials, tissue engineering, and regenerative medicine. In recent years, because of outstanding flexibility and multipotency, polymeric LbL thin films have been extensively studied to create a biomimetic cellular microenvironment with one or more biophysical and biochemical properties. The field has moved from simple mimicking to active control of various cellular behaviors. This review first introduces the basic background of the natural cellular microenvironment, the LbL assembly, and progress in polymeric LbL thin films. Next, biomimetic films constructed using the LbL technique are introduced. The biochemical components, topographical features, and mechanical properties of the films are detailed. Furthermore, progress in thin LbL films for controlling cell behavior, such as cell adhesion, stem cell differentiation, and cell-cell interactions, are highlighted. Finally, the review closes with a summary and a brief outlook of the opportunities and challenges associated with polymeric LbL thin films for advancing promising future developments. (C) 2019 Elsevier B.V. All rights reserved.