Dopamine-Functionalized Gold Nanoparticles for Colorimetric Detection of Histamine

Histamine, a primary biogenic amine (BA) generated through the decarboxylation of amino acids, concentration increases in protein-rich foods during deterioration. Thus, its detection plays a crucial role in ensuring food safety and quality. This study introduces an innovative approach involving the direct integration of dopamine onto gold nanoparticles (DCt-AuNP), aiming at rapid histamine colorimetric detection. Transmission electron microscopy revealed the aggregation of uniformly distributed spherical DCt-AuNPs with 12.02 +/- 2.53 nm sizes upon the addition of histamine to DCt-AuNP solution. The Fourier-transform infrared (FTIR) spectra demonstrated the disappearance of the dicarboxy acetone peak at 1710 cm(-1) along with the formation of well-defined peaks at 1585 cm(-1), and 1396 cm(-1) associated with the N-H bending modes and the aromatic C=C bond stretching vibration in histamine molecule, respectively, confirming the ligand exchange and interactions of histamine on the surface of DCt-AuNPs. The UV-vis spectra of the DCt-AuNP solution exhibited a red shift and a reduction in surface plasmon resonance (SPR) peak intensity at 518 nm along with the emergence of the 650 nm peak, signifying aggregation DCt-AuNPs with increasing histamine concentration. Notably, color transitions from wine-red to deep blue were observed in the DCt-AuNP solution in response to histamine, providing a reliable colorimetric signal. Dynamic Light Scattering (DLS) characterization showed a significant increase in the hydrodynamic diameter, from similar to 15 to similar to 1690 nm, confirming the interparticle cross-linking of DCt-AuNPs in the presence of histamine. This newly developed DCt-AuNP sensor provides colorimetric results in less than a minute that exhibits a remarkable naked-eye histamine detection threshold of 1.57 mu M and a calculated detection limit of 0.426 mu M, making it a promising tool for the rapid and sensitive detection of histamine.