Effects of gamma rays and neutron irradiation on the glucose response of boronic acid-containing “smart” hydrogels

If a biomaterial is to be implanted in the body, it must be subjected to a sterilization procedure which often involves gamma irradiation. We report results for the effects of γ-irradiation on the glucose response of a hydrogel with glucose-binding boronic acid moieties. This 'smart” hydrogel is of a type suitable for use in non-enzymatic glucose sensors. In addition, the effect of neutron irradiation on the glucose response of these hydrogels is also of interest, because the hydrogels could be used with minor modification to deliver boron to tumors during boron neutron capture therapy (BNCT). We show that the glucose response of the smart hydrogels is unaffected by exposure to neutrons in the dose range typical for BNCT. The effect of gamma rays on the glucose response depends on the method used to cure the smart hydrogel. If the hydrogel is cured with a thermal free-radical-initiator, then the hydrogel can be sterilized by gamma irradiation with no adverse effects upon the glucose response. However, if the hydrogel is cured with a UV-initiated free radical initiator, then the glucose response decreases in magnitude with increase in the gamma radiation dose.