Hierarchical Polymer Brushes with Dominant Antibacterial Mechanisms Switching from Bactericidal to Bacteria Repellent

Abstract

Although polycationic surfaces have high antimicrobial efficacies, they suffer from high toxicity to mammalian cells and severe surface accumulation of dead bacteria. For the first time, we propose a surface-initiated photoiniferter-mediated polymerization (SI-PIMP) strategy of constructing a "cleaning" zwitterionic outer layer on a polycationic bactericidal background layer to physically hinder the availability of polycationic moieties for mammalian cells in aqueous service. In dry conditions, the polycationic layer exerts the contact-active bactericidal property toward the adherent bacteria, as the zwitterionic layer collapses. In aqueous environment, the zwitterionic layer forms a hydration layer to significantly inhibit the attachment of planktonic bacteria and the accumulation of dead bacteria, while the polycationic layer kills bacteria occasionally deposited on the surface, thus preserving the antibacterial capability for a long period. More importantly, the zwitterionic hydrated layer protects the mammalian cells from toxicity induced by the bactericidal background layer, and therefore hierarchical antibacterial surfaces present much better biocompatibility than that of the naked cationic references. The dominant antibacterial mechanism of the hierarchical surfaces can switch from the bactericidal efficacy in dry storage to the bacteria repellent capability in aqueous service, showing great advantages in the infection-resistant applications.

Polymer‐Based Surfaces Designed to Reduce Biofilm Formation: From Antimicrobial Polymers to Strategies for Long‐Term Applications

“…After reloading the surfaces with lysozyme, the surface activity was regenerated . In the context of regeneration by washing, Yin and coworkers presented moderately dense block copolymer brushes with a polycationic core and a polyzwitterionic shell . These polymers killed 76% of S. aureus bacteria and about 95% of E. coli in the dry state.…”

“…These polymers killed 76% of S. aureus bacteria and about 95% of E. coli in the dry state. 73% of adhered S. aureus bacteria and 90% of adhered E. coli bacteria could be released in the wet state from these bifunctional materials . It was assumed that the dry material exposed its antimicrobial core, while the swollen material consisted of a polyzwitterionic corona that covered that shell, and thus prevented bacterial adhesion.…”

Antibacterial and antifouling properties of a polyurethane surface modified with perfluoroalkyl and silver nanoparticles

“…However, these methods also have some limitations which suffer from burst release, drug resistance, and result in the increasing of biofilm. Recently, many efforts have been made to integrate the strength of the above two antibacterial approaches into a single platform …”

“…Recently, many efforts have been made to integrate the strength of the above two antibacterial approaches into a single platform. [21][22][23][24] Multi-segmented polyurethanes are extensively used as catheter material own to their flexibility, low toxicity and physiological inertness. However, biomaterial caused infectious constrain their biomedical applications.…”

Polydopamine Nanocoating for Effective Photothermal Killing of Bacteria and Fungus upon Near‐Infrared Irradiation

“…There are three dominant strategies to combat and prevent the bacterial colonization on surfaces: adhesion resistance, contact killing, and biocide leaching . However, the anti‐adhesion surfaces usually using hydrophilic compounds such as polyethylene glycol easily lose their functions in varying environment such as dry conditions; the contact‐killing surfaces would suffer environmental contamination and be toxicity to adhered mammalian cells possibly; and in the case of biocide leaching surfaces, where antibiotics and heavy metal ions have been employed, lead to severe issue of antibiotic‐resistance and dubious damage to human body and environment, respectively . Alternative strategies to broaden the range of bactericidal surface design are therefore imperative …”