Preparation and characterization of glucose oxidase nanoparticles and their application in dissolved oxygen metric determination of serum glucose.

The nanoparticle (NP) aggregates of commercial glucose oxidase (GOD) from A. niger with 117 nm diameter, were prepared by desolvation method. The formation and characterization of GOD-NP aggregates was studied by UV, transmission electron microscopic (TEM) and Fourier transform infrared (FTIR) spectra. GOD-NP aggregates were more stable, active and had a higher shelf life than that of free enzyme. These GOD-NP aggregates were immobilized onto chitosan activated nitrocellulose (NC) membrane through glutaraldehyde coupling with 55.15% retention of initial activity of free enzyme and 5.9 microg protein/cm2 yield. The membrane bound GOD-NP aggregates showed optimum response within 60 s, at pH 6.0, temperature range 30-45 degrees C with a peak at 35 degrees C and a hyperbolic relationship with glucose upto 250 mg/dl. Apparent K(m) and V(max) were 75 mg/dl and 0.06 mg/l respectively. The NC membrane bound GOD-NP aggregates were employed for dissolved O2 (DO) metric determination of serum glucose in apparently healthy and diabetic adults. The present method of serum glucose determination was evaluated.