Synthesis of gold nanoparticles (AuNPs) with tyrosin supporting agent as colorimetry sensor against Escherichia coli (E.coli) bacteria

Gold nanoparticles (AuNPs) can be applied as a biosensor for Escherichia coli bacteria. The sensory ability of AuNPs can be increased by the presence of a hood in the form of tyrosine. At present, it has been investigated the synthesis of gold nanoparticles with 0.5 mM gold solution, reduced using a chemical method with an ascorbic acid reducing agent in a mole ratio of 1: 4 resulting in the maximum wavelength absorption in UV-Vis spectrophotometry is of 525.40 nm. After adding a covering agent in the form of tyrosine, It was found that the absorption wavelength was 534 nm.The result produced was applied as a sensor in the liquid media preparation of Escherichia coli bacteria concentrations of 108, 106, 104 ,dan 102 CFU/mL, resulting in an absorption wavelength of 680 nm and a bathochromic shift indicatingthe formation of bonds between AuNPs-Tyrosin-Escherichia coli.