Inspired by the long-term effectiveness of living antifouling materials, we have developed a method for the self-replenishment of synthetic biofouling-release surfaces. These surfaces are created by either molding or directly embedding 3D vascular systems into polydimethylsiloxane (PDMS) and filling them with a silicone oil to generate a non-toxic oil-infused material. When replenished with silicone oil from an outside source, these materials are capable of self-lubrication and continuous renewal of the interfacial fouling-release layer. Under accelerated lubricant loss conditions, fully-infused vascularized samples retained significantly more lubricant than equivalent non-vascularized controls.
Tests of lubricant-infused PDMS in static cultures of the infectious bacteria Staphylococcus aureus and Escherichia coli as well as the green microalgae Botryococcus braunii, Chlamydomonas reinhardtii, Dunaliella salina, and Nannochloropsis oculata showed a significant reduction in biofilm adhesion compared to PDMS and glass controls containing no lubricant. Further experiments on vascularized versus non-vascularized samples that had been subjected to accelerated lubricant evaporation conditions for up to 48 h showed significantly less biofilm adherence on the vascularized surfaces. These results demonstrate the ability of an embedded lubricant-filled vascular network to improve the longevity of fouling-release surfaces.
Cartoon of bio-inspired fouling-release surface
(A) Schematic of the process to make either infused PDMS or vascularized, infused PDMS. For simple infused PDMS (upper row), cured PDMS is placed in a bath of silicone oil which diffuses into the PDMS solid. For vascularized PDMS, the vascular pattern is created before curing. The sample is then infused externally with silicone oil in the same manner as the non-vascularized PDMS, or internally through filling the vascular network, or both. (B) Methods of creating vascular networks within PDMS: 1) An encased network is created using a 3D mold (a) to create the pattern in PDMS (b). The mold is removed from the cured PMDS (c) and the pattern is covered with a second sheet of PDMS (d and e) which is chemically bonded to the pattern using plasma. (i) an image of a 3D leaf vasculature network after encasing. 2) An embedded network is created following the procedures developed by Lewis et al. (citation). (a) A pattern of 20% w/w pluronic F127 gel at 25 °C is embedded in uncured PDMS. (b) The PDMS is allowed to cure, cooled to 4 °C, and the liquid pluronic is evacuated. (c) The channel is refilled with silicone oil. (i) An image of fluorescently dyed PDMS in a hand-drawn sinuous channel, (ii) a hand-drawn leaf-shape network, and (iii) a 3D-printed linear network.
A) Quantification of the amount of biofilm remaining on these surfaces compared to unlubricated controls (CtrlD) and samples that had undergone no lubricant evaporation (0h). The samples with embedded vasculature show significantly less adherent biofilm at all time points (P0.05). (B) Representative images of control samples and samples with an embedded vascularized network after evaporation of the lubricant for 1, 2, 4, 8, 24, and 48 hours and subsequent exposure to E. coli for 48 hours (purple color is from crystal violet staining).
Inspired by the long-term effectiveness of living antifouling materials, we have developed a method for the self- replenishment of synthetic biofouling-release surfaces. These surfaces are created by either molding or directly embedding 3D vascular systems...
