M13 phage as network frame for the quantification of Pb based on the Pb-induced in-situ growth of gold nanoparticles.

Routine detection of Pb is of great importance to environmental monitoring because of its deleterious effects on human health and environment. In this work, an easy-to-operate method for the one-step detection of Pb was developed based on the phage-Pb interactions and their influence on the surface plasmon resonance (SPR) absorption band of AuNPs. AuNPs grow in-situ on the surface of M13 phages and the resulting phage-AuNP networks were directly used for lead sensing. The addition of Pb facilitates further growth of the parent AuNPs and results in a blue shift of the SPR absorption peak. By integrating AuNPs preparation and sensing procedure into one step, a simplified Pb detection approach was developed with improved sensitivity and shortened analysis time. By quantifying A with UV-vis spectrometer, a linear range of 0.5-5.0 μmol L together with a limit of detection of 45 nmol L was obtained. The one-step approach avoided complicated AuNPs preparation and functionalization process, and got rid of the unstable problems of AuNPs for long-term preservation, offering simple and cost-effective Pb detection method for resource-poor settings.