A critical aspect in the development of biomaterials is the optimization of their surface properties to achieve an adequate cell response. In the present work, electrospun polycaprolactone nanofiber meshes (NFMs) are treated by radio-frequency (RF) plasma using different gases (Ar or O(2)), power (20 or 30 W), and exposure time (5 or 10 min). Morphological and roughness analysis show topographical changes on the plasma-treated NFMs. X-ray photoelectron spectroscopy (XPS) results indicate an increment of the oxygen-containing groups, mainly --OH and --C==O, at the plasma-treated surfaces. Accordingly, the glycerol contact angle results demonstrate a decrease in the hydrophobicity of plasma-treated meshes, particularly in the O(2)-treated ones. Three model cell lines (fibroblasts, chondrocytes, and osteoblasts) are used to study the effect of plasma treatments over the morphology, cell adhesion, and proliferation. A plasma treatment with O(2) and one with Ar are found to be the most successful for all the studied cell types. The influence of hydrophilicity and roughness of those NFMs on their biological performance is discussed. Despite the often claimed morphological similarity of NFMs to natural extracellular matrixes, their surface properties contribute substantially to the cellular performance and therefore those should be optimized.

Polymers have gained a remarkable place in the biomedical field as materials for the fabrication of various devices and for tissue engineering applications. The initial acceptance or rejection of an implantable device is dictated by the crosstalk of the material surface with the bioentities present in the physiological environment. Advances in microfabrication and nanotechnology offer new tools to investigate the complex signaling cascade induced by the components of the extracellular matrix and consequently allow cellular responses to be tailored through the mimicking of some elements of the signaling paths. Patterning methods and selective chemical modification schemes at different length scales can provide biocompatible surfaces that control cellular interactions on the micrometer and sub-micrometer scales on which cells are organized. In this review, the potential of chemically and topographically structured micro- and nanopolymer surfaces are discussed in hopes of a better understanding of cell-biomaterial interactions, including the recent use of biomimetic approaches or stimuli-responsive macromolecules. Additionally, the focus will be on how the knowledge obtained using these surfaces can be incorporated to design biocompatible materials for various biomedical applications, such as tissue engineering, implants, cell-based biosensors, diagnostic systems, and basic cell biology. The review focusses on the research carried out during the last decade.

Sulfation is a dynamic and complex posttranslational modification process. It can occur at various positions within the glycosaminoglycan (GAG) backbone and modulates extracellular signals such as cell-cell and cell-matrix interactions; different sulfation patterns have been identified for the same organs and cells during their development. Because of their high specificity in relation to function, GAG sulfation patterns are referred to as the sulfation code. This review explores the role of GAG sulfation in different biological processes at the cell, tissue, and organism levels. We address the connection between the sulfation patterns of GAGs and several physiological processes and discuss the misregulation of GAG sulfation and its involvement in several genetic and metabolic disorders. Finally, we present the therapeutic potential of GAGs and their synthetic mimics in the biomedical field.