Biosensor for mercury ion detection using a virus and silver nanoparticle composite

Colorimetric Mercury Ion Sensor Based on EEEE Peptide-M13 Phage and Silver Nanoparticle Composites

This technology is a biosensor that optically detects mercury(II) ions in aqueous solutions using a nanobio-composite that combines M13 viruses expressing tetraglutamic acid (EEEE) peptides on their surface with silver nanoparticles stabilized by a silicate sol-gel matrix.

Mercury is a lethal heavy metal that causes nervous system damage, but it is nearly impossible to detect directly through spectral analysis, forcing most sensors to rely on molecular probes and labeling tags. Composites combining biomolecules and nanomaterials have also faced limitations due to the need for recognition motifs to maintain stability between the two.

In this technology, the carboxyl groups of the peptide pre-concentrate mercury ions to induce a reaction with silver nanoparticles, identifying mercury through the quenching of the surface plasmon resonance band and a color change from yellow to colorless due to AgHg amalgam formation. It produces silver nanoparticles without reducing agents and lowers production costs for M13 and silver nanoparticles, maintaining high selectivity even in samples with many interfering substances. It can be applied to on-site heavy metal monitoring of industrial wastewater and drinking water, allowing for rapid verification of mercury contamination without expensive analytical equipment.

‍

‍

Key Features:

• Cloning step to express an EEEE sequence peptide consisting of four glutamic acids on the surface of the M13 virus major coat protein P8
• Step of obtaining M13 virus phage with surface-expressed EEEE peptides via reverse transcription PCR cloning using primers of SEQ ID NO: 1 and 2
• Step of forming silver nanoparticles by adding AgNO3 solution to a silicate sol-gel matrix solution without adding a reducing agent
• Step of mixing M13 virus phage and silver nanoparticles to obtain a nanocomposite where the SPR absorption band is quenched upon mercury ion binding

‍