Surface‐Grafted Polystyrene Beads with Comb‐Like Poly(ethylene glycol) Chains: Preparation and Biological Application

Abstract

We prepared surface-grafted polystyrene (PS) beads with comb-like poly(ethylene glycol) (PEG) chains. To accomplish this, conventional gel-type PS beads (35-75 microm) were treated with ozone gas to introduce hydroperoxide groups onto the surface. Using these hydroperoxide groups, poly(methyl methacrylate) (PMMA, Mn= 22,000-25,000) was grafted onto the surface of the PS beads. The ester groups of the grafted PMMA were reduced to hydroxyl groups with lithium aluminum hydride (LAH). After adding ethylene oxide (EO) to the hydroxyl groups, we obtained the PS-sg-PEG beads, which had a rugged surface and a diameter of 80-150 microm. We could obtain several kinds of the PS-sg-PEG beads by controlling the chain lengths of the grafted PMMA and the molecular weights of the PEG chains. The grafted PEG layer was about 30-50 microm thick, which was verified from the cross-sectioned views of the fluorescamine-labeled beads. These fluorescence images proved that the beads possessed a pellicular structure. Furthermore, we found that the surface-grafted PEG chains had the characteristic property of reducing non-specific protein adsorption on the beads.

Immunoassay Interference by a Commonly Used Blood Collection Tube Additive, the Organosilicone Surfactant Silwet L-720

“…Silwet L-720, the silicone surfactant used by BD for coating the interior of their blood collection tubes (17,20 ), is a member of a family of nonionic silicone surfactants that contain hydrophilic polyoxyalkylene chains. Typically, they exist as homopolymers or copolymers of polyoxyethylene and polyoxypropylene and are attached to a hydrophobic polydimethylsiloxane backbone (1,(21)(22)(23). The molecular structure of Silwet L-720 can be either comb-like, with the polyoxyalkylene chain side-grafted on a polydimethylsiloxane backbone, or linear, arranged with either the AB or ABA type configuration, with A representing a polyoxyalkylene hydrophile and B a polydimethylsiloxane hydrophobe (1,(21)(22)(23).…”

“…Typically, they exist as homopolymers or copolymers of polyoxyethylene and polyoxypropylene and are attached to a hydrophobic polydimethylsiloxane backbone (1,(21)(22)(23). The molecular structure of Silwet L-720 can be either comb-like, with the polyoxyalkylene chain side-grafted on a polydimethylsiloxane backbone, or linear, arranged with either the AB or ABA type configuration, with A representing a polyoxyalkylene hydrophile and B a polydimethylsiloxane hydrophobe (1,(21)(22)(23). The polydimethylsiloxane moiety of Silwet L-720 adsorbs to hydrophobic surfaces such as the plastic (i.e., polyethylene terephthalate) in blood collection tube walls, whereas the hydrophilic, polyalkylene oxide moiety faces outward toward the specimen and prevents erythrocyte adherence (1,3,(21)(22)(23).…”

“…The molecular structure of Silwet L-720 can be either comb-like, with the polyoxyalkylene chain side-grafted on a polydimethylsiloxane backbone, or linear, arranged with either the AB or ABA type configuration, with A representing a polyoxyalkylene hydrophile and B a polydimethylsiloxane hydrophobe (1,(21)(22)(23). The polydimethylsiloxane moiety of Silwet L-720 adsorbs to hydrophobic surfaces such as the plastic (i.e., polyethylene terephthalate) in blood collection tube walls, whereas the hydrophilic, polyalkylene oxide moiety faces outward toward the specimen and prevents erythrocyte adherence (1,3,(21)(22)(23). The findings from this study demonstrate that the addition of increasing concentrations of Silwet L-720 (0 to 400 mg/L) to a serum pool from glass tubes significantly increased the apparent TT 3 concentration when measured on the IMMULITE 2500 analyzer (Fig.…”

Effects of ozone in surface modification and thermal stability of SEBS block copolymers

“…Moreover, ozone treatment of polymers has been used as a useful method of creating reactive hydroperoxide groups that allows further chemical modification [6]. This procedure opens new channels to obtain interesting new building bricks in block copolymers that heretofore has not been studied exhaustively but which holds great promise for self-assembly.…”

Formation of hydrated layers in PMMA thin films in aqueous solution

“…Because of this, information about the response of these films to a wide range of external stimuli is becoming more and more important. Although most applications are in dry environments, analysis of PMMA films in aqueous solutions is of relevance because of their potential as coatings for various types of medical implants [5][6][7] and general use in other applications where protective surface coatings in aqueous solution are required. Studying PMMA films in situ in aqueous solutions is challenging, but neutron reflectometry has been previously used in various studies which characterise thin films of hydrated polymers prepared via spin-coating, in particular with studies of glass transition temperature (T G ) [11,12] and solvent retention [13,14].…”