Stimuli-sensitive hydrogel material for biosensor-chemical trigger

The mutual influence of urea hydrolysis catalyzed with urease immobilized into a poly-N-isopropylacrylamide gel and shrinking-swelling of the thermosensitive urease-containing gel have been studied. The collapsed gel has been shown to reswell during urea hydrolysis catalyzed with urease. Immobilized urease reveals a sharp increase in the activity at low substrate concentrations under the collapsed gel conditions. Urea hydrolysis catalyzed with immobilized urease can be used to “switch” activity of coimmobilized α-chymotrypsin under the gel collapse conditions. The triggered character of the ureasecontaining system and its possible mechanism are discussed.