The Impact of Virgin and Aged Microstructured Plastics on Proteins: The Case of Hemoglobin Adsorption and Oxygenation.

Plastic particles, particularly micro- and nanoparticles, are emerging pollutants due to the ever-growing amount of plastics produced across a wide variety of sectors. When plastic particles enter a biological medium, they become surrounded by a corona, giving them their biological identity and determining their interactions in the living environment and their biological effects. Here, we studied the interactions of microstructured plastics with hemoglobin (Hb). Virgin polyethylene microparticles (PEMPs) and polypropylene microparticles (PPMPs) as well as heat- or irradiation-aged microparticles (ag-PEMPs and ag-PPMPs) were used to quantify Hb adsorption. Polypropylene filters (PP-filters) were used to measure the oxygenation of adsorbed Hb. Microstructured plastics were characterized using optical microscopy, SAXS, ATR-FTIR, XPS, and Raman spectroscopy. Adsorption isotherms showed that the Hb corona thickness is larger on PPMPs than on PEMPs and Hb has a higher affinity for PPMPs than for PEMPs. Hb had a lower affinity for ag-PEMPs and ag-PPMPs, but they can be adsorbed in larger amounts. The presence of partial charges on the plastic surface and the oxidation rate of microplastics may explain these differences. Tonometry experiments using an original method, the diffuse reflection of light, showed that adsorbed Hb on PP-filters retains its cooperativity, but its affinity for O2 decreases significantly.

Efficient adsorption of hemoglobin from aqueous solutions by hybrid monolithic cryogel column.

In this study, a supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based Cu2+-attached bentonite particles embedded hybrid monolithic cryogel (Cu2+-ABPs EHMC) was prepared by radical cryo-copolymerization of HEMA with N,N'-methylene-bis-acrylamide (MBAAm) as a cross-linker directly in a plastic syringe in the presence of Cu2+-ABPs, and used for hemoglobin (Hb) separation from aqueous solution. Due to the naturally abundant hydroxyl groups on bentonite, Cu2-attached bentonite particles (Cu2+-ABPs) embedded hybrid monolithic cryogel (HMC) showed a good adsorption performance for Hb, covering an excellent adsorption capacity of 521.6mg/g bentonite in phosphate buffer at pH6.0 with a flow rate of 0.5mL/min, fast binding stability within 60min, well selectivity and reversibility. Compared with other adsorbent systems used for protein separation, this sorbent has many advantages such as excellent adsorption performance, ease of preparation, suitable, effective and environment-friendly to perform, which can serve as a more sustainable material in protein separation and purification.