Optimal pyoverdin-CPG composites for development of an optical biosensor to detect iron

Abstract

Optical fluorescence-quenching-based biosensing cell is described and optimization of covalent binding of highly selective natural iron-chelating peptide secreted by bacteria is suggested. Pyoverdin biosynthesized by Pseudomonas monteilii and having 70% iron chelating activity was immobilized on amino alkylated controlled pore glass (CPG) and cross-linked with glutaraldehyde (2.5%, 28°C, 30 min). The pyoverdin-CPG immobilization was confirmed using fluorescence microscopic images (excitation range, 465–495 nm) for bright green fluorescence and by FTIR spectrum stretching at 3406.4 cm⁻¹ for amino group. The pyoverdin loading capacity of activated CPG matrix was 25 mg g⁻¹ of CPG and its rinsing analysis (leaking profile of the immobilized peptide vs. washing) detected negligible (2–3 μg) pyoverdin in the second wash.