An antiadhesion and antibacterial platform based on parylene F coatings

Abstract

As an excellent barrier material, parylene has been widely used in plenty of fields. However, conventional parylenes cannot endure medical sterilization procedures, including high-temperature sterilization and ultraviolet disinfection, which restrict their medical applications. A new parylene member, Parylene F, overcomes the above drawbacks and shows potential in medical applications. In this work, parylene F (type AF4) was deposited on two polydimethylsiloxane (PDMS) substrates through chemical vapor deposition (CVD) method, and the thickness of parylene F was 1 μm (PDMS-PF-1) and 5 μm (PDMS-PF-5), respectively. For the first time, we investigated the antifouling property and biocompatibility of parylene F. We found an interesting phenomenon that parylene F demonstrated dual-action antifouling activities—antiadhesion and antibacterial. For gram-negative bacteria Escherichia coli, the fouled area to the total area ratios on PDMS-PF-1 (0.69 ± 0.25 %) and PDMS-PF-5 (0.5 ± 0.1 %) were significantly lower than that on the pristine PDMS (6 ± 0.77 %). The antibacterial ratios (dead/total bacteria) of PDMS-PF-1 (45.49 ± 9.58 %) and PDMS-PF-5 (45.3 ± 8.8 %) were higher than that of the pristine PDMS (28.12 ± 3.26 %). Similar results were also observed in the tests against gram-positive bacteria Bacillus subtilis. The synergistic effect of antiadhesion and antibacterial characteristics endowed the surface with excellent antifouling properties. These results indicated that the thickness of parylene F had a close relationship to its antiadhesion performance, while not affecting the antibacterial activity. Additionally, this study revealed that parylene F exhibited good light transmittance (PDMS-PF-1 > 83 % and PDMS-PF-5 > 81 % in the visible wavelength) and excellent biocompatibility (relative cell viability > 86 %). These excellent properties mean that parylene F can act as a potential candidate for medical and related applications.