Interaction Between Meat Extract Proteins and Microplastics

The increasing prevalence of microplastic pollution poses significant risks to ecosystems and human health. Considering that a substantial portion of meat and meat products are packaged in plastic1, it is crucial to investigate the potential interactions between meat proteins and plastic. Furthermore, microplastics (MP) can be retained in the gastrointestinal tract (GIT) and interact with dietary proteins, including meat proteins. This interaction is particularly relevant in the context of alpha-Gal syndrome (AGS), caused by a reaction to the carbohydrate galactose-alpha-1,3-galactose (α-Gal) epitope found in red meat proteins2. The prolonged presence of α-Gal-containing proteins in the GIT due to interactions with microplastics could contribute to AGS.
This study explores the interaction between red meat extract proteins and MPs made from polypropylene (PP) and polyethylene terephthalate (PET). Beef meat was minced, and proteins were extracted using simulated saliva fluid. One milligram of MPs (PET or PP) was incubated with 20 mg of meat extract proteins for 2 hours at room temperature and 37°C in simulated intestinal fluid (SIF). Post-incubation, MPs were removed by centrifugation and rinsed three times to obtain soft corona proteins, while hard corona proteins were obtained by boiling MPs in Laemmli buffer. Bulk, soft, and hard corona proteins were resolved via PAA SDS-PAGE, and protein bands from the electropherograms were excised and subjected to mass spectrometry (MS) analysis.
Our findings reveal that the interaction of red meat proteins with microplastics (PP and PET) results in the significant formation of both soft and hard protein corona layers around the microplastic particles. Binding at different temperatures (room temperature and 37°C) under identical pH conditions (SIF, pH 7) shows a higher presence of hard corona proteins at 37°C, notably with an abundant protein band of approximately 36 kDa. MS analysis identified multiple peptides from different proteins in this molecular weight band. However, it is most likely that this band originates from one subunit of the enzyme glyceraldehyde-3-phosphate dehydrogenase.