Smart, Photothermally Activated, Antibacterial Surfaces with Thermally Triggered Bacteria-Releasing Properties

Abstract

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.

Surface Design for Antibacterial Materials: From Fundamentals to Advanced Strategies

“…Reproduced with permission. [ 136 ] Copyright 2020, American Chemical Society. e,f) Strategy of triggered bacterial killing.…”

“…Due to the presence of cationic biocide and nanopatterned PNIPAM brushes, nearly 81 ± 4% of attached bacteria were removed from the surface. Furthermore, Wang et al [ 136 ] grafted PNIPAM onto tannic acid (TA)/Fe 3+ ion complex to form a self‐cleaning coating on Au substrate. This coating exhibited high photothermal bacteria‐killing efficiency (>99%) under the irradiation of NIR light, and thermal‐triggered self‐cleaning performance (removing >90% of the attached bacteria) (Figure 5d ).…”

“…d) A TA/Fe-PNIP coating on Au surface to clean bacteria by thermal responsive size-changing. Reproduced with permission [136]. Copyright 2020, American Chemical Society.…”

Antimicrobial surfaces: a review of synthetic approaches, applicability and outlook

“…Qian et al have developed switchable surfaces with bacteria killing and releasing ability using tannic acid/Fe 3+ (TA/Fe) ion complex as a photothermal bactericidal agent and PNIPAAm as an antifouling material. TA/Fe showed biocidal activity against E. coli and methicillin resistant Staphylococcus aureus (MRSA) on exposure to NIR and all the dead bacteria were released from the surface at a temperature lower than the LCST of PNIPAAm [ 114 ]. Similarly, another switchable surface with photothermal bactericidal activity has been developed by Qian et al In this work, instead of using stimuli responsive polymer for switching the activities they have used gold nanoparticle layer and phase-transitioned lysozyme film (GNPL-PTNF).…”

Thermo-Tunable Pores and Antibiotic Gating Properties of Bovine Skin Gelatin Gels Prepared with Poly(n-isopropylacrylamide) Network

“…The most abundant species to colonize burn wounds among species present in normal skin microflora is Staphylococcus aureus (6.5–37.6%) [ 2 ]. Antibacterial agents for the treatment of skin infections, including burns, in hospitals have favored the emergence of smart antibiotic releasing during serious opportunistic infection; therefore, it is essential [ 3 ].…”