Exploration of PETase side activity of digestive enzymes of human gastrointestinal tract acting on micro- and nanoplastics: mode of action and products characterization

Project acronym:   XPACT

Project type:   PRISM

Grant agreement No.:   HF-182

     

Project is funded by:   Science Fund of the Republic of Serbia (Belgrade, Serbia)

Instituions where the research is conducted:

• Institute of Chemistry, Technology and Metallurgy (Belgrade, Serbia) – Beneficiary
• University of Belgrade - Faculty of Chemistry (Belgrade, Serbia) – Coordination

Project realization is scheduled from December 1, 2023 till November 30, 2026.

Project staff

Short description of the project

Background: Polyethylene terephthalate (PET) is the most frequently found polymer type detected in human blood. Side-products of PET polymerization reaction are cyclic and linear oligomers of PET, also detected in human blood and recently recognized as non-intentionally added substances in food, due to their migration from the food packaging materials. The aim of the proposed project is in-depth investigation of the transformation processes of PET micro- and nanoplastics (MNPs) during simulated in vitro digestion in the gastrointestinal tract (GIT).

Methods: PET MPs upon exposure to digestive enzymes will be characterized chemically by microFTIR for the presence of characteristic chemical modifications. Transformations of PET NPs will be monitored by DLS (size and zeta potential). PET oligomers released in the fluids by the action of enzymes on PET MNPs will be screened by LC/HRMS. Bioavailability will be investigated in a Caco-2 cell model of intestinal epithelium. Experimental methods will be complemented with in silico predictions.

Novelty: XPACT project is challenging one of the major paradigms of modern society, that plastic is safe because it does not degrade by our digestive tract. Small fragments of plastics (MNPs) in its properties may significantly differ from the original material, and exhibit a higher susceptibility to hydrolytic and oxidative conditions in the GIT. We hypothesize that digestion will facilitate release of smaller PET fragments from PET MNPs by passive diffusion or by breaking of the internal ester bonds.

Impact: Our understanding of the digestive transformations and faith of this important type of plastics in the GIT can urge regulatory authorities to more tightly monitor and control release of MNPs, particularly PET based, into environment and promote use of non-plastic based solutions for food packaging.

Expected results: XPACT will deepen our understanding of the transformation processed occurring at PET MNPs, as well products released in the intestinal fluids. To fully investigate the faith of PET MNPs in the GIT we will apply state-of-the art methodology and develop innovative solutions for monitoring PET oligomers by HRMS and PET MNPs modification that may later on be used in other applications.