Development of Bioinspired Antimicrobial Surfaces for Pathogen Spread Control


Student thesis: Doctoral Thesis

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Award date9 Apr 2021


Surface-deposited pathogens, such as bacteria, fungi, and viruses, are critical sources of spreading infectious diseases in communities and healthcare settings. Protecting public facilities with antimicrobial coatings is a promising approach to control pathogen spread. Two main strategies have been reported to develop antimicrobial surfaces: antifouling surfaces by reducing microorganisms’ adhesion and bactericidal surfaces by killing microorganisms attached to the surface. However, there were some limitations when they were applied in particular scenarios. Based on the two kinds of strategies, we developed novel antimicrobial surfaces with unique features by mimicking the biological structures or functions to address the issues in some particular application scenarios directly.

In the first part, mucus-inspired supramolecular organogel was developed to directly address the pathogen-contained microdroplets issue via a unique mechanism of Wrapping-layer Assisted Releasing. The organogel was designed by mimicking airway mucus’s structure and function and possessed combined features of excellent fouling-release, readily damage healing, rapid and persistent disinfection. It could disinfect microdroplets rapidly by providing an antimicrobial wrapping layer so that the bactericidal molecules were enhanced released into microdroplets. Furthermore, the persistent fouling-release and damage-healing properties would significantly extend the organogel coating’s lifespan, making it promising to be applied in healthcare settings or public areas to control pathogen spread under indoor environments.

In the second part, molecular interaction controlling strategy was developed to optimize antimicrobial organogel performance and broaden the potential application. Through well-controlled interaction between the phytochemical liquid encapsulated and the network, antimicrobial organogels with high stiffness and high antimicrobial efficiency were developed. This strategy broadens our toolbox to design antimicrobial organogels. We envision that not only polymer with various non-covalent interaction motifs and backbones could be introduced, but also other molecules with biological activities can be involved to provide complementary means in the fight against bacteria/virus or other applications.

In the third part, bioinspired nanostructure surfaces were fabricated to disinfect bacteria-contained microdroplets at a superfast rate. We fabricated surfaces with nanostructures by mimicking the structure of cicada wings, and we found the liquid bridges that connect bacteria, nanowires, and liquid were formed on these surfaces. The capillary-supported liquid bridges could spontaneously trap, deform, and kill droplet-carried bacteria. We utilized this strategy to disinfect pathogen-contained respiratory microdroplets and fabricated long-term antibacterial medical masks by integrating ZnO nanowires onto flexible polypropylene melt-blown nonwoven fabrics, indicating liquid bridge’s great potential as an antiseptics-free broad-spectrum highly-efficient antibacterial strategy.

In summary, we designed bioinspired antimicrobial surfaces with unique features by utilizing the interface between the bacteria-contained liquid and antimicrobial surfaces. The antimicrobial surfaces designed could disinfect microdroplets rapidly with the Wrapping-layer Assisted Releasing mechanism or liquid bridge’s assistance. We envision that our interface design strategies and bioinspired antimicrobial surfaces developed have great potential to control pathogen spread in practical.