Phytochelatins are small peptides that can be found in several organisms, which use these oligopeptides to handle heavy metal elements. Here, we report a method for monitoring interactions between lead(II) ions in aqueous solutions and phytochelatin 6 oligopeptide bioconjugated onto pegylated gold nanorods (PEG-AuNrs). This study is the first step towards a high sensitive label free optical biosensor to quantify heavy metal pollution in water.