Multienzyme-immobilized modified polypropylene membrane for an amperometric creatinine biosensor

Creatinine has become an important clinical analyte that is used for the determination of renal and muscular dysfunction. It is essential to determine its concentration in the serum of patients suffering from renal insufficiency. Therefore, an amperometric creatinine biosensor fabricated from a covered platinum/silver electrode with a thin layer of an immobilized multienzyme membrane was studied. Poly(acrylic acid) was introduced onto an argon-plasma-treated porous polypropylene membrane surface by graft copolymerization. Subsequently, three different enzymes (sarcosine oxidase, creatinase, and creatininase) were immobilized onto this novel grafted membrane simultaneously via a carbodiimine agent to form a thin layer. The sensor performance was evaluated with a biochemistry analyzer. Moreover, attenuated total reflection/ Fourier transform infrared, electron spectroscopy for chemical analysis, and scanning electron microscopy were used to confirm the progression of these reactions. The developed sensor showed a linear detection range of 3.2-320 muM for creatinine in a pH 7.4 buffered solution with 0.1M phosphate. The immobilized multienzyme membrane could be used for at least 3 weeks. The results obtained in our study will hopefully lead to the successful application of modified polypropylene for the development of a creatinine sensor. (C) 2004 Wiley Periodicals, Inc.