Every year a large part of western countries' medical charges is assigned to medical care of patients suffering from tissues and/or organs alterations. Health centers spend for this purposes more than 10 million euro/year and this expense grow continuously due to the population mean age's increase. Tissue engineering (TE) represents a valid alternative to organ/tissue transplantation. A fundamental step for TE is the cell seeding directly on porous tridimensional artificial structures called scaffolds. However on artificial polymer scaffolds made of PCL or PLA as an example often higher cell colonization at the periphery and inadequate colonization at the center of the scaffold were noted due to the hydrophobic character of the materials [1,2]. In this work a single and multistep innovative approaches based on plasma technology are proposed as an interesting alternative. A plasma deposition of Polyethylene oxide like (PEO-like) coatings is proposed alone and in combination with O2 plasma treatment to stimulate cell ingrowth.

In this work, the response of Saos2 cells to polymeric surfaces with different roughness/density of nanometric dots produced by a tailored plasma-etching process has been studied. Topographical features have been evaluated by atomic force microscopy, while wetting behavior, in terms of water-surface adhesion energy, has been evaluated by measurements of drop sliding angle. Saos2 cytocompatibility has been investigated by scanning electron microscopy, fluorescent microscopy, and optical microscopy. The similarity in outer chemical composition has allowed isolation of the impact of the topographical features on cellular behavior. The results indicate that Saos2 cells respond differently to surfaces with different nanoscale topographical features, clearly showing a certain inhibition in cell adhesion when the nanoscale is particularly small. This effect appears to be attenuated in surfaces with relatively bigger nanofeatures, though these express a more pronounced slippery/dry wetting character. © 2011 American Chemical Society.

Cellular adhesion and proliferation inside three-dimensional synthetic scaffolds represent a major challenge in tissue engineering. Besides the surface chemistry of the polymers, it is well recognized that scaffold internal architecture, namely pore size/shape and interconnectivity, has a strong effect on the biological response of cells. This study reports for the first time how polycaprolactone (PCL) scaffolds with controlled micro-architecture can be effectively produced via bioextrusion and used to enhance the penetration of plasma deposited species. Low-pressure nitrogen-based coatings were employed to augment cell adhesion and proliferation without altering the mechanical properties of the structures. X-ray photoelectron spectroscopy carried out on different sections of the scaffolds indicates a uniform distribution of nitrogen-containing groups throughout the entire porous structure. In vitro biological assays confirm that plasma deposition sensitively promotes the activity of Saos-2 osteoblast cells, leading to a homogeneous colonization of the PCL scaffolds. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Plasma Processes and Polymers

The behavior of cells in terms of cell-substrate and cell-cell interaction is dramatically affected by topographicalcharacteristics as shape, height, and distance, encountered in their physiological environment. The combinationof chemistry and topography of a biomaterial surface influences in turns, important biological responses asinflammatory events at tissue-implant interface, angiogenesis, and differentiation of cells. By disentangling theeffect of material chemistry from the topographical one, the possibility of controlling the cell behavior can beprovided. In this paper, surfaces with different roughness and morphology were produced by radiofrequency (RF,13.56 MHz) glow discharges, fed with hexafluoropropylene oxide (C3F6O), in a single process. Coatings withdifferent micro/nanopatterns and the same uppermost chemical composition were produced by combining twoplasma deposition processes, with C3F6O and tetrafluoroethylene (C2F4), respectively. The behavior of osteoblastlikecells toward these substrates clearly shows a strict dependence of cell adhesion and proliferation on surfaceroughness and morphology.

A Functional Bio-Interlayer Organic Field-Effect Transistor (FBI-OFET) sensor, embedding a streptavidin protein capturing layer, capable of performing label-free selective electronic detection of biotin at 3 part per trillion (mass fraction) or 15 pM, is proposed here. The response shows a logarithmic dependence spanning over 5 orders of magnitude of analyte concentration. The optimization of the FBI analytical performances is achieved by depositing the capturing layer through a controllable Layer-by-Layer (LbL) assembly, while an easy processable spin-coating deposition is proposed for potential low-cost production of equally highly performing sensors. Furthermore, a Langmuirian adsorption based model allows rationalizing the analyte binding process to the capturing layer. The FBI-OFET device is shown to operate also with an antibody interlayer as well as with an ad hoc designed microfluidic system. These occurrences, along with the proven extremely high sensitivity and selectivity, open to FBI-OFETs consideration as disposable electronic strip-tests for assays in biological fluids requiring very low detection limits.

In this paper, we describe the deposition of PEO-like coatings using dielectric barrier discharges (DBDs) fed with aerosols of the TEGDME organic precursor in helium. By properly tuning plasma parameters such as aerosol/carrier flow ratio, frequency of the electric field applied and input power, the deposition process could be modulated to obtain coatings with variable PEO character, from 50% (cell adhesive) to 70% (nonfouling), which are interesting for surface modification of biomaterials and biomedical devices.