Bulk and Thin Film Carbon Materials for Biomedical Applications: Quality Control Criteria and Procedures

Vallana, F.; Arru, P; Santi, Marta

doi:10.1007/978-94-011-2896-4_64

Cited by 1 publication

(1 citation statement)

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“…This is probably the reason for the higher variability in terms of opening pressure during the 4‐month fatigue cycles, for the PDMS + DLC valves. DLC coatings have been proposed in the cardiovascular field and claimed as possible functional coatings to improve the hemocompatibility of cardiac and aortic valves 20‐23 . Such coatings did not interfere with the opening performance of the valves; however, the opening dynamics of cardiac/aortic valves are very different from the one featuring the polymeric valve proposed in this study and usable in artificial sphincters.…”

Section: Discussionmentioning

confidence: 65%

PDMS and DLC‐coated unidirectional valves for artificial urinary sphincters: Opening performance after 126 days of immersion in urine

et al. 2021

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In this work, unidirectional valves made of bare polydimethylsiloxane (PDMS) and PDMS provided with a micrometric diamond-like carbon (DLC) coating were fabricated and characterized, in terms of surface properties and opening pressure. The valve performance was also tested over 1250 repeated cycles of opening/closure in water, finding a slight decrease in the opening pressure after such cycles (10%) for the PDMS valves, while almost no variation for the PDMS + DLC ones. The valves were then immersed in urine for 126 days, evaluating the formation of encrustations and the trend of the opening pressure over time. Results showed that PDMS valves were featured by a thin layer of encrustations after 126 days, but the overall encrustation level was much smaller than the one shown by PDMS in static conditions. Furthermore, the opening pressure was almost not affected by such a thin layer of crystals. DLC-coated valves showed even less encrustations at the same time-point, with no significant loss of performance over time, although they were featured by a higher variability. These results suggest that most encrustations can be removed by the mechanical action of the valve during daily openings/closures. Such a selfcleaning behavior with respect to a static condition opens exciting scenarios for the long-term functionality of mobile devices operating in the urinary environment.

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Section: Discussionmentioning

confidence: 65%