[Soft Matter Café] Here to stay? Polystyrene interaction with model lipid membranes

In little more than a century, synthetic plastic oligomers have gone from being hailed as a scientific wonder to being reviled as an environmental plague. Plastic is lightweight, tough, transparent, waterproof. These characteristics become a drawback when it was firstly noticed that the degradation of plastic waste can enter the food chain and finally interact with living organisms’ cells. Physicochemical characterization of the effects of synthetic polymers on the structure and dynamics of cell membranes is thus of primary importance. To study the interactions between short chains of polystyrene and model lipid membranes (DPPC, in both gel and fluid phases) we combined a wide spectrum of experimental techniques exploiting neutron and Xrays scattering in combination with PSCM laboratory techniques (calorimetry, Langmuir, QCMD, BAM).
We find that doping doses of polystyrene oligomers alter the thermal properties of DPPC, stabilizing the fluid lipid phase. They perturb the membrane structure and dynamics, in a concentration-dependent fashion. Eventually, they modify the mechanical properties of DPPC, reducing its bending modulus in the fluid phase. Our results call for a systematic, interdisciplinary assessment of the mechanisms of interaction of synthetic, everyday-use polymers with cell membranes.

About the speaker: graduated in Physics at Sapienza university of Rome, with a master thesis in soft matter physics (NMR applied to frescoes conservation). Approaching the biophysics field, she completed her PhD at Ancona, Università Politecnica delle Marche (UNIVPM Ancona), focusing her research interests on bio-soft matter by means of scattering techniques to study the structural organization and dynamics of biomimetic colloids, in particular protein arrangement and interactions on different length-scales. She moved to Milan for her post-Doc and is now researcher in Università Statale di Milano (UNIMI), characterizing the structural and thermotropic properties of lipid membranes, self-aggregation of peptides and proteins, interaction of peptides and polymers with model membranes.