A total internal reflection fluorescence biosensor for aluminum (III)

Total internal reflection fluorescence (TIRF) is widely used for investigating interfacial interactions. It has proven to be a well-suited technique for biosensing applications due to its surface sensitivity and minimal sample consumption. In this paper, the protein phosvitin has been investigated as a molecular sensor for the detection of aluminum (III). Phosvitin was labeled with fluorescein isothiocyanate (FITC) and immobilized on a quartz surface via EDC/NHS chemistry. Phosvitin-FITC and aluminum complexation, both in free solution and surface-bound form, was studied. A TIRF biosensor selective for Al3+ was constructed using surface-immobilized phosvitin-FITC. An enhancement of phosvitin-FITC fluorescence intensity was observed upon addition of Al3+. The response was linear over the range 0.1-10 muM of aluminum concentration. (C) 2001 Elsevier Science B.V. All rights reserved.