fig1

Figure 1. Methodology overview for the nAu sensor for the detection of NPs. Gold nanoparticles (nAu) of 10 nm diameter are first labeled for 24 hr to mercaptoundecanoic acid (MUA) to form nAu-MUA (A). The nAu-MUA complexes are separated from unreacted MUA by centrifugation and resuspension in 10% ethanol. The nAu-MUA is colored violet in the presence of 5 mM HCl in the absence of NPs (B). When it binds to the hydrophobic NPs, the violet color (610 nm) changes to a red wine color (550-580 nm) in a concentration-dependent manner^[16]. MUA: Mercaptoundecanoic acid; NPs: nanoplastics; nAu: nanogold.