Figure 3.

Methodologic principle of the GoldC test described by Srisrattakarn A. and colleagues [128], which is based on hydrolysis of the β-lactam ring of imipenem by carbapenemases, resulting in an acid product. In the presence of acid, the repulsive force between the AuNPs is eliminated, and thus the inter-particle distance is decreased. This leads to AuNP aggregation, which can be detected by the change in the AuNP solution from red to purple, blue, or green (positive). The AuNP solution remains red (negative) in the absence of acid production. Scheme taken from Srisrattakarn A. et al. [128].