PFOS and PFOA interaction with organic chromophore bound serum albumin

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are persistent in water bodies and are highly thermal and chemically stable, making them non-biodegradable. When bound with proteins, this can pose health risks. Several detection methods involving; chromatography, mass spectrometry, and other PFOS/PFOA detection procedures are time-consuming. Here, fluorescence spectroscopy is used to probe PFOS and PFOA by utilizing a chromophore-bound serum albumin complex based on the squaraine (SQ) dye's photophysical properties. The prepared SQ herein interacted with bovine serum albumin (BSA) which forms SQ-BSA complex and showed strong fluorescence signal. Subsequent PFOS and PFOA addition revealed a gradual fluorescence turn-on and turn-off respectively, which continued to change along these two directions up to 20 μM. Overall, these sequentially studied tri-component systems (SQ, BSA, PFOS/PFOA) discriminative response relies on the SQ-BSA's different interacting behaviors with PFOS and PFOA. The discrimination ability of PFOS and PFOA by the SQ-BSA complex becomes ascribed by the different interacting abilities of these two harmful pollutants with BSA amongst various studies. Therefore, the result shows potential new insights towards PFAS discrimination study and offers mechanistic insight into how PFOS and PFOA may influence albumin structures.