Biosensors, extracorporeal devices and methods for detecting substances using crosslinked protein crystals

摘要

Proteins such as enzymes and antibodies are immobilized by crosslinking crystals of the proteins such as microcrystals having a cross-section of 10-1 mm or less with a multifunctional crosslinking agent. The crosslinked protein crystals may be lyophilized for storage. Crystals of an enzyme such as thermolysin, elastase, asparaginase, lysozyme, lipase or urease may be crosslinked to provide crosslinked enzyme crystals that retain at least 91% activity after incubation for three hours in the presence of a concentration of Pronase TM that causes the soluble uncrosslinked form of the enzyme to lose at least 94% of its initial activity under the same conditions. A preferred Pronase TM :enzyme ratio is 1:40. Crosslinked enzyme or antibody crystals may be used in an assay, diagnostic kit or biosensor for detecting an analyte, in an extracorporeal device for altering a component of a fluid, in producing a product such as using crosslinked thermolysin crystals to produce aspartame, in separating a substance from a mixture, and in therapy.