Plasma Methods for the Generation of Chemically Reactive Surfaces for Biomolecule Immobilization and Cell Colonization ‐ A Review

Abstract

Summary: This review surveys methods for the fabrication, by plasma surface treatments or plasma polymerization, of polymeric surfaces and thin plasma polymer coatings that contain reactive chemical groups useful for the subsequent covalent immobilization, by solution chemical reactions or vapor phase grafting, of molecules or polymers that can exert bio‐specific interfacial responses. Surfaces containing amine, carboxy, hydroxy, and aldehyde groups are the subject of this review. Aminated surfaces have been fabricated using various plasma vapors or mixtures and have found wide use for bio‐interface applications. However, in many cases the amine surfaces have a rather limited shelf life, with post‐plasma oxidation reactions and surface adaptation leading to the disappearance of amine groups from the surface. Aging is a widespread phenomenon that often has not been recognized, particularly in some of the earlier studies on the use of plasma‐fabricated surfaces for bio‐interfacial applications, and can markedly alter the surface chemistry. Plasma‐fabricated surfaces that contain carboxy groups have also been well documented. Fewer reports exist on hydroxy and aldehyde surfaces prepared by plasma methods. Hydroxy surfaces can be prepared by water plasma treatment or the plasma polymerization of alkyl alcohol vapors. Water plasma treatment on many polymer substrates suffers from aging, with surface adaptation leading to the movement of surface modification effects into the polymer. Both hydroxy and aldehyde surfaces have been used for the covalent immobilization of biologically active molecules. Aging effects are less well documented than for amine surfaces. This review also surveys studies using such surfaces for cell colonization assays. Generally, these surface chemistries show good ability to support cell colonization, though the effectiveness seems to depend on the process vapor and the plasma conditions. Carboxylate co‐polymer surfaces have shown excellent ability to support the colonization of some human cell lines of clinical interest. Immobilization of proteins onto plasma‐carboxylated surfaces is also well established.XPS O/C ratios (00 emission) as a function of storage time, of plasma‐polymerized methyl methacrylate deposited at power levels of 5 and 40 W.magnified imageXPS O/C ratios (00 emission) as a function of storage time, of plasma‐polymerized methyl methacrylate deposited at power levels of 5 and 40 W.

Immobilization of superoxide dismutase/catalase onto polysulfone membranes to suppress hemodialysis-induced oxidative stress: A comparison of two immobilization methods

“…Moreover, in some conditions lowered stability of bioactive molecules due to usage of spacers can be prevented [14]. A key challenge for the plasma treatment process is aging as a result of post-plasma oxidation initiated by the reaction between remaining radicals and in-diffusing atmospheric oxygen as well as the movement of some of the polymer chains from the surface into the bulk [15]. Recently, adsorption of enzymes on polyelectrolyte-modified membrane surfaces has emerged as a versatile, gentle and easy method for immobilization [16][17][18][19][20][21] which occurs mainly via ionic binding of enzyme molecules to the charged surface.…”

Universal hydrophilic coating of thermoplastic polymers currently used in microfluidics

“…A general drawback to gas phase methods such as UV/ozone, corona, and various types of plasma treatments is the rapid aging of their surface (24). The plasma degrades a thin layer of the material and produces low molecular weight (Mw) oxidized polymer chains on the surface, which causes a hydrophilization that is rapidly lost in solvents due to the dissolution of low Mw chains [25].…”

Acetylene plasma-polymer films treated by argon plasma immersion ion implantation

“…Oxygen and nitrogen gases were not purposely introduced into the deposition process; therefore, their presence is attributed to the post reaction of long-lived radicals trapped in the polymeric structure, particularly when the samples were removed from the plasma reactor (18,19) . As can be observed, after argon PIII treatment O/C atomic ratio increases from 0.23 to 2.43, while N/C one vanishes probably due to the creation of volatile nitrogen compounds that were etched from the film surfaces.…”