Effects of crystalline structures on protein repellent property of ultrathin homopolymer thin films

Fouling is the undesirable accumulation of a material on a wide variety of objects and has now become a widespread global problem from land to ocean with both economic and environmental penalties. Recently, we reported protein repellent properties of ultrathin polymer films that are considered to be of structural origin and generalizable across amorphous homopolymer systems¹. In this talk, ultrathin semicrystalline homopolymer films (≥ 100 nm thick) composed of isotactic polypropylene, low-density polyethylene, and poly(lactic acid) were subject to protein adsorption test against two model plasma proteins: fluorescein labeled bovine serum albumin (BSA) and fibrinogen. The stock protein solutions were diluted in phosphate-buffered saline (PBS) at a resultant protein concentration of 1 mg/ml in PBS for BSA and 0.1 mg/ml in PBS for fibrinogen. The polymer films were incubated in the protein solution for 30 min at 25 °C, then extracted and rinsed with water and thereafter dried with a gentle oxygen/nitrogen gas stream. The absorption of the BSA and fibrinogen on the thin film was measured using a photon counting spectrofluorometer. We will discuss the effect of crystalline structures on protein repellent properties.

¹D. Salatto, Y. T. et al., Macromolecules, 2020, 53, 6547.