Parylene outstanding barrier properties restrict the permeation of ions and biological macromolecules, thereby mitigating encrustation through the formation of crystalline deposits such as struvite, carbonated apatite, and weddellite. Notably, parylene F-VT4, demonstrates superior encrustation resistance in simulated urinary flow conditions, with a reduced fouling mass compared to parylene C (1).
When combined with a silicon oxide (SiOx) topcoat, performance is further enhanced, an improvement attributed to the increased surface hydrophilicity and the strongly negative zeta potential imparted by the additional oxide layer.
Taken together, these properties position parylene-based coatings, particularly in their advanced formulations combined with a SiOx finish, as a highly promising encapsulation strategy for extending the operational lifetime and ensuring the long-term reliability of implantable urological MEMS devices.
(1) Buchwalder et al, Polymers 2023, 15, 3559
