Development of a versatile strategy for antibacterial surfaces is of great scientific interest and practical significance. However, few methods can be used to fabricate antibacterial surfaces on substrates of different chemistries and structures. In addition, traditional antibacterial surfaces may suffer problems related to the attached dead bacteria. Herein, antibacterial surfaces with multifunctionality and regenerability are fabricated by a universal strategy. Various substrates are first deposited with multilayered films containing guest moieties, which can be further used to incorporate biocidal host molecules, β-cyclodextrin (β-CD) derivatives modified with quaternary ammonium salt groups (CD-QAS). The resulting surfaces exhibit strong biocidal activity to kill more than 95% of attached pathogenic bacteria. Notably, almost all the dead bacteria can be easily removed from the surfaces by simple immersion in sodium dodecyl sulfate, and the regenerated surfaces can be treated with new CD-QAS for continued use. Moreover, when another functional β-CD derivative molecule is co-incorporated together with CD-QAS, the surfaces exhibit both functions simultaneously, and neither specific biofunction and antibacterial activity is compromised by the presence of the other. These results thus present a promising way to fabricate multifunctional and regenerable antibacterial surfaces on diverse materials and devices in the biomedical fields.
The development of effective antibacterial
surfaces to prevent
the attachment of pathogenic bacteria and subsequent bacterial colonization
and biofilm formation is critically important for medical devices
and public hygiene products. In the work reported herein, a smart
antibacterial hybrid film based on tannic acid/Fe3+ ion
(TA/Fe) complex and poly(N-isopropylacrylamide) (PNIPAAm)
is deposited on diverse substrates. This surface is shown to have
bacteria-killing and bacteria-releasing properties based on, respectively,
near-infrared photothermal activation and subsequent cooling. The
TA/Fe complex has three roles in this system: (i) as a universal adhesive
“anchor” for surface modification, (ii) as a high-efficiency
photothermal agent for ablation of attached bacteria (including multidrug
resistant bacteria), and (iii) as a robust linker for immobilization
of NH2-terminated PNIPAAm via either Michael addition or
Schiff base formation. Moreover, because of the thermoresponsive properties
of the immobilized PNIPAAm, almost all of the killed bacteria and
other debris can be removed from the surface simply by lowering the
temperature. It is shown that this hybrid film can maintain good antibacterial
performance after being used for multiple “kill-and-release”
cycles and can be applied to various substrates regardless of surface
chemistry or topography, thus providing a broadly applicable, simple,
and reliable solution to the problems associated with surface-attached
bacteria in various healthcare applications.
Surfaces having dynamic control of interactions at the biological system-material interface are of great scientific and technological interest. In this work, a supramolecular platform with switchable multivalent affinity was developed to efficiently capture bacteria and on-demand release captured bacteria in response to irradiation with light of different wavelengths. The system consists of a photoresponsive self-assembled monolayer containing azobenzene (Azo) groups as guest and β-cyclodextrin (β-CD)-mannose (CD-M) conjugates as host with each CD-M containing seven mannose units to display localized multivalent carbohydrates. Taking the advantage of multivalent effect of CD-M, this system exhibited high capacity and specificity for the capture of mannose-specific type 1-fimbriated bacteria. Moreover, ultraviolet (UV) light irradiation caused isomerization of the Azo groups from trans-form to cis-form, resulting in the dissociation of the host-guest Azo/CD-M inclusion complexes and localized release of the captured bacteria. The capture and release process could be repeated for multiple cycles, suggesting good reproducibility. This platform provides the basis for development of reusable biosensors and diagnostic devices for the detection and measurement of bacteria and exhibits great potential for use as a standard protocol for the on-demand switching of surface functionalities.
Stimuli-responsive gauze coated with a phase-transitioned lysozyme nanofilm (PTLF@gauze) has been developed, which exhibits great potential for clinical applications by reducing secondary trauma and relieving the pain of patients.
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