Salt-Induced Regenerative Surface for Bacteria Killing and Release

Abstract

Antibacterial surfaces with both bacteria killing and release functions show great promise in biological and biomedical applications, in particular for reusable medical devices. However, these surfaces either require a sophisticated technique to create delicate structures or need rigorous stimuli to trigger the functions, greatly limiting their practical application. In this study, we made a step forward by developing a simple system based on a salt-responsive polyzwitterionic brush. Specifically, the salt-responsive brush of poly(3-(dimethyl (4-vinylbenzyl) ammonium) propyl sulfonate) (polyDVBAPS) was endowed with bactericidal function by grafting an effective bactericide, i.e., triclosan (TCS). This simple functionalization successfully integrated the bacteria attach/release function of polyDVBAPS and bactericidal function of TCS. As a result, the surface could kill more than 95% attached bacteria and, subsequently, could rapidly detach ∼97% bacteria after gently shaking in 1.0 M NaCl for 10 min. More importantly, such high killing efficiency and release rate could be well retained (unchanged effectiveness of both killing and release after four severe killing/release cycles), indicating the highly efficient regeneration and long-term reusability of this system. This study not only contributes zwitterionic polymers by conferring new functions but also provides a new, highly efficient and reliable surface for "killing-release" antibacterial strategy.

Responsive and Synergistic Antibacterial Coatings: Fighting against Bacteria in a Smart and Effective Way

“…The switchable behavior of the above PIL‐based surfaces was mainly due to the fact that imidazolium‐type ionic liquid is counterion‐sensitive; the ion exchange between anionic counterions could induce the hydration and dehydration of PIL brushes and the change in surface charge characteristic and surface wettability. Recently, Yang and coworkers applied a salt‐responsive polyzwitterionic brush of poly(3‐(dimethyl(4‐vinylbenzyl)ammonium)propyl sulfonate) (PDVBAPS) to integrate antibacterial component for development of smart antibacterial coatings . At first, they immobilized a common biocide, TCS, onto the PDVBAPS‐modified surface by a reaction between phenolic hydroxyl groups of TCS and sulfonic pendant groups of PDVBAPS brushes (Figure b).…”

“…[98a] By combining the bactericidal activity of TCS and salt responsiveness of PDVBAPS, they achieved a salt‐responsive antibacterial coating with high bactericidal efficiency and high bacteria‐release capability, as well as high regenerative efficiency, showing great potential in biological and biomedical applications. Later, they applied other strategies to endow the surfaces with both bactericidal function and salt‐triggered bacteria‐release function, including a surface immobilized with mixed polymer brushes of bactericidal poly(2‐( tert ‐butylamino)ethyl methacrylate) (PTBAEMA) and PDVBAPS,[98b] a hybrid hydrogel composed of antimicrobial AgNPs, salt‐responsive PDVBAPS, and antifouling poly( N ‐hydroxyethyl acrylamide),[98d] as well as a two‐layer architecture composed of bactericidal brushes of PTMAEMA or PTBAEMA (the top layer) and salt‐responsive polyzwitterionic brush (PDVBAPS, the bottom layer). [98c] All of these resulting coatings could kill bacteria attached to the surfaces and release the dead bacteria due to the swollen polymer brushes after adding salt solution.…”

“…Later, they applied other strategies to endow the surfaces with both bactericidal function and salt‐triggered bacteria‐release function, including a surface immobilized with mixed polymer brushes of bactericidal poly(2‐( tert ‐butylamino)ethyl methacrylate) (PTBAEMA) and PDVBAPS,[98b] a hybrid hydrogel composed of antimicrobial AgNPs, salt‐responsive PDVBAPS, and antifouling poly( N ‐hydroxyethyl acrylamide),[98d] as well as a two‐layer architecture composed of bactericidal brushes of PTMAEMA or PTBAEMA (the top layer) and salt‐responsive polyzwitterionic brush (PDVBAPS, the bottom layer). [98c] All of these resulting coatings could kill bacteria attached to the surfaces and release the dead bacteria due to the swollen polymer brushes after adding salt solution. In summary, these stimuli‐responsive polymers provide a more practical and convenient approach for fabrication of smart antibacterial coatings.…”

“…Therefore, these surfaces may more or less face the problem of bactericide inactivation during a long‐term service. In addition, one main drawback of smart antibacterial coatings based on release‐killing mechanism (such as AgNP‐based antibacterial materials[92,98d]) is the continuous consumption of free biocides; thus, their bactericidal performance can only be maintained for a period of time. When the bactericidal activity is not enough to kill the attached bacteria on the surface, bacterial contamination will subsequently happen.…”

One-Pot and One-Step Fabrication of Salt-Responsive Bilayer Hydrogels with 2D and 3D Shape Transformations

“…Before use, NIPAM was purified by recrystallization from hexanes. 3-(1-(4-Vinylbenzyl)-1 H -imidazol-3-ium-3-yl)­propane-1-sulfonate (VBIPS) and dimethyl-(4-vinylphenyl)­ammonium propane sulfonate (DVBAPS) were synthesized according to our previous report. ,,− All other chemicals and solvents were commercially obtained at extra-pure grade and were used as received. Water used in these experiments was purified by a Millipore water purification system with a minimum resistivity of 18.0 MΩ cm.…”