Gamma radiation immobilization

An alternative approach to stationary phase immobilization, and the most popular method in contemporary practice, is the free radical crosslinking of the polymer chains, using peroxides [201,202,245-248], azo-oospounds [202,249-251], ozone [252], or gamma radiation [253-255] as free radical generators. In this case, crosslinking occurs through the formation of (Si-C-C-Sl) bonds as shown below ... 

We have investigated the immobilization of water soluble polymers by exposure to gamma radiation (8-10). This chapter... 

Immobilized enzymes have been used for the formation of biosensors that are selective for numerous enzyme substrates (42). We have evaluated the potential of gamma irradiation as a means of immobilizing an enzyme in a polymer matrix on an electrode surface. The previously mentioned advantageous features of the gamma radiation method are potentially useful in the formation of biosensors based on enzymes immobilized in polymer films. 

Gamma radiation from a °Co source has also been used (77,114,132-135) as an effective technique for crosslinking polysiloxanes. In a comparative study of gamma radiation with peroxides, Schomburg et al. (77) noted that each approach immobilized polysiloxanes, but that the formation of polar decomposition products is avoided with radiation. Radiation offers the additional advantages of the crosslinking reaction occurring at room temperature, and columns can be tested both before and after immobilization of the stationary phase. 

Water-soluble polyphosphazenes can be crosslinked either by gamma-radiation or by di- or tri-valent cations. The resultant materials imbibe or extrude water in response to changes in temperature, pH, or cations. These hydrogels offer the prospect of uses in responsive membranes, devices for the controlled delivery of dmgs, enzyme immobilization and mediation media, and tissue engineering. 

Dobo was the first to report an immobilization of an enzyme with radiation [17]. Immobilization of enzymes by gamma-ray polymerization and electron beam crosslinking were studied by Kawashima [18] and Maeda [19], respectively. Kaetsu et al. have studied the immobilization of various biofunctional components by gamma-ray polymerization of supercooled acrylates and methacrylates [20-25]. 

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