Atmospheric Pressure Deposition of Micropatterned Nitrogen‐Rich Plasma‐Polymer Films for Tissue Engineering

Abstract

Summary: A novel atmospheric‐pressure plasma‐polymerised thin film material has been deposited on various substrates using a pilot scale dielectric barrier discharge (DBD) reactor. Deposition kinetics and physico‐chemical characterisation data of nitrogen‐rich plasma‐polymerised ethylene (PPE:N) films, obtained using feed gas mixtures of N2 (ca. 10 slm) and C2H4 (ca. 10 sccm) are described. Nitrogen concentrations, [N], in the PPE:N films up to ca. 40% were determined by XPS; the concentrations of N‐functionality of greatest interest, primary amines, were determined by chemical derivatisation with 4‐trifluoromethylbenzaldehyde. The PPE:N films were further characterised by attenuated total reflectance infra‐red spectroscopy (ATR‐FTIR), contact angle goniometry, and atomic force microscopy (AFM). Square arrays of PPE:N “islands”, for example 30 μm in diameter repeated every 200 μm, were deposited on polymers, for example biaxially oriented poly(propylene) (BOPP), through specially‐prepared Kapton® polyimide masks. Cell culture experiments were then conducted on these micro‐patterned surfaces, using various cell types of interest in orthopaedics, for example growth plate and articular chondrocytes, or human U937 macrophages, the latter of which do not adhere to existing cell culture dishes. In all these cases the cells rapidly adhered and proliferated on the PPE:N islands, but not elsewhere on the polymer surfaces. In an effort to gain insight into cell adhesion mechanisms, adhesion of both macrophages and chondrocytes was tested against films with different [N] values. U‐937 macrophages adhered to films containing 25% or more [N], but not at all to films with lower values of [N], suggesting the existence of a “critical” value, [N]crit, necessary to induce cell adhesion.

Effects of Dielectric Barriers in Radio-Frequency Atmospheric Glow Discharges

“…A TMOSPHERIC pressure glow discharges (APGD) have recently attracted much attention, largely because they offer a chamberless route to many scientific disciplines, including analytical chemistry [1], nanoscience [2], biology and medicine [3]- [5], space exploration [6], and display technologies [7]. Interest in APGD is also motivated by their scope for new low-temperature plasma physics in a highly collisional regime [8].…”

Trends in surface engineering of biomaterials: atmospheric pressure plasma deposition of coatings for biomedical applications

“…It is well known, for example, that nitrogen-rich organic coatings promote cell adhesion and differentiation of mesenchymal stem cells; Marasescu et al [23] have focused their investigations on plasma-deposited N-rich films obtained from C 2 H 4 /NH 3 or C 2 H 4 /N 2 gas mixtures in LP (L-PPE:N) and AP DBD (H-PPE:N) systems, respectively. AP deposited PPE:N coatings were used by Girard et al [26] to produce surfaces with alternated micrometric cell-adhesive and cellrepulsive domains. Square PPE:N arrays were obtained through a micrometric polyimide mask.…”

Non-thermal plasma assisted lithography for biomedical applications: an overview

“…Girard-Lauriault et al [98] fabricated a N-rich surface using a plasma discharge of N 2 and ethylene on a variety of polymeric substrates, while a polyimide mask was used to deposit the patterns. Chondrocyte and U937 macrophage seeding revealed that a minimum of 25% nitrogen incorporation was required to have a good cell adhesion.…”