Poly(dimethyl siloxane) surface modification by low pressure plasma to improve its characteristics towards biomedical applications (original) (raw)
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Plasma surface modification of polymers for biomedical use
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2003
Polymeric materials can be used in many application areas due to their mechanical (e.g. elastic) characteristics, chemical stability, and their light weight, as well as for their many design possibilities. Even in the fields of medicine and biotechnology many products are completely or partly made of polymers. In contact with biological systems, compatibility of these materials is not always given. To fulfill the requirements for medical applications, the surfaces have to be modified. Plasma techniques are demonstrated as an appropriate tool for the generation of the demanded surface properties. Experimental data are given for surface modification by plasma polymerization, with retention of the functional groups of the monomers used. Qualitative and quantitative characterization of the thin films with respect to the type and density of available groups at the surfaces is presented. Some possible applications of plasma-modified polymers are also discussed.
Plasma-surface modification of biomaterials
Plasma-surface modification (PSM) is an effective and economical surface treatment technique for many materials and of growing interests in biomedical engineering. This article reviews the various common plasma techniques and experimental methods as applied to biomedical materials research, such as plasma sputtering and etching, plasma implantation, plasma deposition, plasma polymerization, laser plasma deposition, plasma spraying, and so on. The unique advantage of plasma modification is that the surface properties and biocompatibility can be enhanced selectively while the bulk attributes of the materials remain unchanged. Existing materials can, thus, be used and needs for new classes of materials may be obviated thereby shortening the time to develop novel and better biomedical devices. Recent work has spurred a number of very interesting applications in the biomedical field. This review article concentrates upon the current status of these techniques, new applications, and achievements pertaining to biomedical materials research. Examples described include hard tissue replacements, blood contacting prostheses, ophthalmic devices, and other products. #
Plasma Modification of Biomaterials Controlled by Surface Analysis
Biomaterials are defined as materials to interact or be in contact with biological systems. This paper describes the fumctionalization of soft polymer surfaces against non-specific protein adsorption. A RF plasma changes the chemical composition of a surface within the nm-range, without changing bulk material properties. The chemical control of the surface is assured by X-ray Photoelectron Spectroscopy (XPS) and contact angle measurements (CAM). NH 3 -H 2 treated Polystyrene (PS) chips are used for enhanced biological-immobilization for sensors. Such biosensors use fluorescence immunoassays in medical diagnostics. Pseudomonas aeruginosa is one of the most prevalent bacterial strains in a clinical environment. Teflon-like films deposited on native PVC are used for the preparation of non-fouling surfaces through the physisorption of PEO-PPO-PEO Pluronics ® co-polymers. Secondly, PEO-like and Ag/PEO-like polymers were prepared by plasma polymerization techniques.
Preparation, characterization, and cellular interactions of collagen-immobilized PDMS surfaces
Journal of Applied Polymer Science, 2008
Multistep procedure to biofunctionalization of (poly)dimethylsiloxane (PDMS) surfaces is present here, including plasma-based Ar 1 beam treatment; acrylic acid grafting; and flexible PEG spacer coupling prior to the collagen immobilization by peptide synthesis reaction. The success of any step of the surface modification is controlled by XPS analysis, contact angle measurements, SEM, and AFM observations. To evaluate the effect of PEG chain length, three diNH 2 PEGs (2000, 6000, and 20,000 D) of relative long polymer chain were employed as a spacer, expecting that a long flexible spacer could provide more conformational freedom for the collagen molecules and fibroblast reorganization to further cellular matrix formation. Human fibroblast cells were used as a model to evaluate the biological response of the collagen-immobilized PDMS surfaces. It is found that the earlier described biofunctionalization is one more road to improvement of the cellular interaction of PDMS, the last one being the best when PEG spacer with moderate chain length, namely of 6000 D, is used.
The effects of PEG-based surface modification of PDMS microchannels on long-term hemocompatibility
Journal of Biomedical Materials Research Part A, 2014
The current study demonstrates the first surface modification for poly(dimethylsiloxane) (PDMS) microfluidic networks that displays a long shelf life as well as extended hemocompatibility. Uncoated PDMS microchannel networks rapidly adsorb high levels of fibrinogen in blood contacting applications. Fibrinogen adsorption initiates platelet activation, and causes a rapid increase in pressure across microchannel networks, rendering them useless for long term applications. Here, we describe the modification of sealed PDMS microchannels using an oxygen plasma pre-treatment and poly(ethylene glycol) grafting approach. We present results regarding the testing of the coated microchannels after extended periods of aging and blood exposure. Our PEG-grafted channels showed significantly reduced fibrinogen adsorption and platelet adhesion up to 28 days after application, highlighting the stability and functionality of the coating over time. Our coated microchannel networks also displayed a significant reduction in the coagulation response under whole blood flow. Further, pressure across coated microchannel networks took over 16 times longer to double than the uncoated controls. Collectively, our data implies the potential for a coating platform for microfluidic devices in many blood-contacting applications.
Journal of Applied Polymer Science, 2009
Assuming that the existence of an ion-flow in the plasma volume could strength the surface modifying effect, including its durability, a parallel plate reactor in reactive ion etching mode was employed to obtain surface modified PDMS with improved cellular interaction. The discharge power was varied at 100, 1200, and 2500 W to ensure varied ion-flow density. The changes in the surface topography were observed by SEM and AFM, and the surface roughness was characterized by both: mean roughness, R a , and root-mean-square, R q . Time dependent water contact angle measurements were performed to control the durability of the hydrophilizing effect. Anisotropic etching, accompanied with decrease of the PDMS surface roughness, was observed up to discharge power of 1200 W that turns in intense isotropic one, accompanied with a sharp increase of the surface roughness over 1200 W, most probably because of arise of reverse sputtered neutrals diffracting the main plasma Ar þ flow. Human fibroblasts were applied as an in vitro model to learn more about the initial cellular interaction of the modified surfaces and to identify the optimal treatment conditions.