Search

Due to the widespread presence of nanoplastics (NPs) in daily essentials and drinking water, the potential adverse effects of NPs on human health have become a global concern. Human serum albumin (HSA), the most abundant and multi-functional protein in plasma, has been chosen to understand the biological effects of NPs after entering the blood. The esterase activity and the transport of bisphenol A in the presence of polystyrene nanoplastics (PSNPs) under physiological conditions (pH 4.0 and 7.4) have been investigated to evaluate the possible biological effects. The interactions between PSNPs and HSA have also been systematically studied by multispectral methods and dynamic light scattering techniques. The esterase activity of HSA presented a decreased trend with increasing PSNPs; conversely, higher permeabilities are accompanied by higher amounts of PSNPs. Compared with the unchanged hydrodynamic diameter and weaker interactions at pH 7.4, stronger binding between HSA and PSNPs at pH 4.0 led to a significant increase in the particle size of the PSNPs-HSA complex. The quenching mechanism belonged to the static quenching type. The electrostatic force is proposed to be the dominant factor for PSNPs binding to HSA. The work provides some information about the toxicity of NPs when exposed to humans. [Display omitted] • PSNPs can disrupt the conformation and function of HSA. • PSNPs quenched the fluorescence of HSA by static binding modes. • At pH 4.0, the binding of PSNPs to HSA was stronger. • The electrostatic interaction between PSNPs and HSA can be regulated by acidity. [ABSTRACT FROM AUTHOR]

Nanoplastics (NPs) and antibiotics have attracted more attention due to the potential toxicity to humans. Studies on their interactions as well as their subsequent combinations can provide useful information for understanding their health risks. In this study, bovine serum albumin (BSA) was used as the model protein to study the effects of polystyrene nanoplastics (PSNPs) on the binding of ciprofloxacin (CPFX) to BSA. The results showed that both the esterase-like activity of BSA in the presence and absence of PSNPs presented an increasing trend when increasing CPFX, and the enhancement when adding PSNPs could be attributed to the alteration of BSA conformation caused by PSNPs. The spectral analysis results indicated that the intrinsic fluorescence quenching of BSA in presence of CPFX is less affected by PSNPs, and PSNPs cannot directly affect the interactions between BSA and CPFX. Additionally, the binding experiments indicated that the presence of PSNPs is likely to promote the binding of CPFX to BSA molecules. This work will provide useful information on the influences of NPs to the health risks of antibiotics, and new insights into the toxic effects in the scene of co-existence. [Display omitted] • Potential toxic effects of co-existence with CPFX and PSNPs on bovine serum albumin. • The presence of PSNPs is likely to promote the binding of CPFX to BSA molecules. • PSNPs enhance esterase-like activities of BSA-CPFX system by indirect interaction. [ABSTRACT FROM AUTHOR]