Improved biocompatibility of parylene‐C films prepared by chemical vapor deposition and the subsequent plasma treatment

Abstract

The purpose of this study is to prepare the thin film of C-type parylene (C-type polyxylylene, parylene-C) with improved biocompatibility for the biomedical applications, since in spite of the popularity, the parylene-C has been known to have the less biocompatibility than the N-type or D-type parylene. To prepare the welldesigned parylene films through the chemical vapor deposition (CVD) process and the subsequent plasma surface treatment, the parameters of deposition and surface modification were controlled to obtain optimized physical and surface properties. Using CVD, the thin films of parylene-C as thick as 5 lm were prepared under different deposition pressures. When increasing the deposition rate of parylene film or the deposition pressure, the tensile strength of film increased, whereas the properties such as the surface contact angle and permeability, and the elongation decreased. The deposition rate could be controlled to optimize the physical and physiochemical properties of films. The hydrophilicity of the parylene-C film increased after plasma surface treatment by showing the larger water contact angle than untreated one. When the radio frequency power was above 100 W in the plasma process, the thin film obtained reveals an excellent cytotropism. It shows the improved biocompatibility with living cells.

The dual role of Parylene C in chemical sensing: Acting as an encapsulant and as a sensing membrane for pH monitoring applications

“…3d depicts the I D -V GS curves of selectively treated sensors tested 45 and 90 days after plasma exposure respectively, indicating that H + sensitivity is slightly lower in the long-term, nevertheless, it still persists. The induced hydrophilicity of oxygen plasma treated Parylene C has been previously attributed to the formation of free carboxyl groups that are prone to bind with hydrophilic molecules [13,14]. The reactions that take place between the hydrophilic groups result in a diminished number of free binding sites on the film surface.…”

“…Many research efforts have been realized to alter the hydrophobic properties of Parylene C with particular focus on the biomedical applications. Oxygen plasma treatment has been previously employed to effectively modify the surface properties of such films [13,14], with special emphasis on utilizing the material as a cell culture substrate [15,16]. In other studies, Parylene has been employed for patterning cells and proteins either by enhancing attachment of proteins after UV exposure [17], or as a peel-off stencil [18].…”

The Effect of Parylene-C Coating on the Surface Free Energy, Water Sorption, Solubility and Staining of PMMA

“…There are several variations of Parylene based on its monomer derivatives [16]. Parylene-C is a thermoplastic, crystalline and transparent polymer that is extensively used as a coating for insulating implantable biomedical devices [17].…”

Maskless, High‐Precision, Persistent, and Extreme Wetting‐Contrast Patterning in an Environmental Scanning Electron Microscope

“…[42][43][44][45] It is also worth noting that the XPS analysis did not show noticeable changes in oxygen content of the surface. The effect of the electron beam through water vapor is therefore different from oxygen plasma treatment, which is well known to increase the hydrophilicity of parylene-C. [46][47][48][49] Furthermore, the effect of an oxygen plasma treatment tends to weaken in a few days as the parylene-C film recovers some of its hydrophobicity. [50] In our method the patterns retain superhydrophilicity even after a year, making the treatment practically permanent.…”