E. coli K-12 asparaginase-based asparagine biosensor for leukemia.

The present work aims at the development of a novel, diagnostic biosensor for monitoring asparagine levels in leukemia. Various immobilization strategies have been applied to improve the stability of the biocomponent (asparaginase). Response time studies have been carried out for different immobilization methods. Phenol Red indicator has been coimmobilized with asparaginase and color visualization approach has been optimized for various asparagine ranges. The detection limit of asparagine achieved with nitrocellulose membrane is 10(-1) M, with silicon gel is 10(-10)-10(-1) M, and with calcium alginate beads is 10(-9)-10(-1) M. Furthermore, the calcium alginate bead system of immobilization has been applied for the asparagine range detection in normal and leukemia serum samples.