FT-IR microscopy characterization of sol-gel layers prior and after glucose oxidase immobilization for biosensing applications

Micro-Attenuated Total Reflection (ATR) Fourier Transform Infrared spectroscopy was used to investigate sol-gel layers for biosensing applications prior and after glucose oxidase (GOD) immobilization. The changes occurring in sol-gel infrared spectrum after GOD immobilization were clearly evidenced confirming the retaining of the enzyme activity. Moreover, micro-ATR experimental technique allowed us to investigate the spatial distribution of enzyme concentration. The non-destructive nature of our approach also enabled to monitor the time stability of sol-gel layers and of embedded GOD. The temporal evolution of some peaks in infrared spectra of these sol-gel layers was compared with absorption and steady-state fluorescence measurements. The results reported here confirm that micro-ATR infrared spectroscopy can be usefully employed for a non- or minimally invasive detailed characterization of supports for enzyme immobilization.