Producing Fluorine- and Lubricant-Free Flexible Pathogen- and Blood-Repellent Surfaces Using Polysiloxane-Based Hierarchical Structures

Abstract

High-touch surfaces are known to be a major route for the spread of pathogens in healthcare and public settings. Antimicrobial coatings have, therefore, garnered significant attention to help mitigate the transmission of infectious diseases via the surface route. Among antimicrobial coatings, pathogen-repellent surfaces provide unique advantages in terms of safety in public settings such as instant repellency, affordability, biocompatibility, and long-term stability. While there have been many advances in the fabrication of biorepellent surfaces in the past two decades, this area of research continues to suffer challenges in scalability, cost, compatibility with high-touch applications, and performance for pathogen repellency. These features are critical for high-touch surfaces to be used in public settings. Additionally, the environmental impact of manufacturing repellent surfaces remains a challenge, mainly due to the use of fluorinated coatings. Here, we present a flexible hierarchical coating with straightforward and cost-effective manufacturing without the use of fluorine or a lubricant. Hierarchical surfaces were prepared through the growth of polysiloxane nanostructures using n-propyltrichlorosilane (n-PTCS) on activated polyolefin (PO), followed by heat shrinking to induce microscale wrinkles. The developed coatings demonstrated repellency, with contact angles over 153°and sliding angles <1°. In assays mimicking touch, these hierarchical surfaces demonstrated a 97.5% reduction in transmission of Escherichia coli (E.coli), demonstrating their potential as antimicrobial coatings to mitigate the spread of infectious diseases. Additionally, the developed surfaces displayed a 93% reduction in blood staining after incubation with human whole blood, confirming repellent properties that reduce bacterial deposition.

Design Principles for Immunomodulatory Biomaterials

“…Also, highly negatively or positively charged latex particles enable thrombogenesis while hydrophilic, low-charged particles suppress thrombogenesis in platelet-rich plasma, , highlighting the need to balance ionic and hydrophobic interactions. For simplicity, however, a design principle is to use hydrophilic biomaterials such as poly(ethylene glycol) and poly(sulfobetaine) or superhydrophobic ones such as polysiloxane- and perfluorocarbon-based biomaterials to mitigate FBR. − Mechanistically, in hydrophilic biomaterials, a tightly bound hydrated layer can effectively impede protein adsorption and interaction with immune cells. At the same time, superhydrophobicity can successfully repel blood components, attenuating the adsorption of blood proteins.…”

Micro‐/Nanohierarchical Structures Physically Engineered on Surfaces: Analysis and Perspective

“…When used as the primary component of hierarchical structures, wrinkles mainly provide highly dense multiscale curved structures with extremely large specific surface areas, mechanical robustness, and stretchability. [5,42,52,53,[82][83][84][85][86][87][88][89][90] The fabrication of such structures has been inspired by the abundance of wrinkles in nature, as exemplified by plant surfaces [91] and fingerprints. [30] To mimic these designs, researchers have developed several methods of fabricating multilayered structures (e.g., stiff skin layers and soft substrates), as exemplified by the plasma treatment of elastomer substrates, [30] attachment of two different layers, [92] and use of a sacrificial skin layer.…”

Superhydrophobic Biological Fluid‐Repellent Surfaces: Mechanisms and Applications

“…After decades of intensive research, numerous methods have been proposed to construct super-repellent surfaces, including but not limited to chemical etching, nanoimprint lithography, dip-/spray-/and spin-coating, chemical vapor deposition, templating, hydrothermal, layer-bylayer deposition, and electrochemical methods. [41][42][43][44][45][46][47][48][49][50][51][52][53][54] Surface micro/nano structures currently applied to SBFRSs include nanofibers, [55][56][57][58] nanoparticles, [59] nanofibers/nanoparticle composite structures, [60][61][62] porous structures, [63][64][65][66] hierarchical structures, [67][68][69][70] wrinkles, [71] fine surfaces, [72][73][74] and rough surfaces. [75][76][77] For instance, by growing and transferring nanowires to polydimethylsiloxane (PDMS), Tripathy and colleague [55] created a surface with both blood-repellency and antibacterial properties.…”