Enhanced Light‐Driven Antimicrobial Activity of Cationic Poly(oxanorbornene)s by Phthalocyanine Incorporation into Polymer as Pendants

Abstract

Amphiphilic poly(oxanorbornene)s are promising synthetic polymers that mimic the structural properties and antimicrobial functions of naturally occurring antimicrobial peptides. Here, poly(oxanorbornene)s bearing pendant zinc(II) phthalocyanine and triphenyl(ethyl) phosphonium functionalities are synthesized by ring‐opening metathesis polymerization (ROMP). Fluorescence, singlet oxygen and triplet quantum yields of polymers are measured in dimethyl sulfoxide and aqueous medium. The singlet oxygen quantum yields of copolymers with the highest triphenyl and triethyl phosphonium content are found to be 0.29 and 0.41, respectively. Then, antimicrobial activities of polymers against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are investigated under both dark and light conditions. Synergistic effect of zinc(II) phthalocyanine and phosphonium‐containing poly(oxanorbornene) is observed that the conjugate possessing the most triphenyl phosphonium side chains has the highest activity under light against both gram‐positive and gram‐negative bacterial strains after 80 min irradiation, reducing the survival of E. coli or S. aureus by 99.9999%. Hemolytic concentrations of the copolymers are found between 8 and 512 µg mL−1. Scanning electron microscopy (SEM) proves that the bacteria membrane deforms after contacting with the biocidal polymer.

Antimicrobial Photodynamic Therapy: Latest Developments with a Focus on Combinatory Strategies

“…Hence, such polymers are adequate for potential aPDT applications [305,306]. Exemplary amphiphilic or cationic poly(oxanorbornene)s doped with PSs, which exhibit pronounced antimicrobial activity (99.9999% efficiency) against E. coli and S. aureus strains, have been reported [307]. By contrast, anionic polymer particles and nanocarriers with negatively charged surfaces and membranes invade the reticuloendothelial system, which leads to elongated blood circulation times [308][309][310].…”

Solvent Effects in Grafting-through Ring-Opening Metathesis Polymerization

“…ROMP, nonetheless, can have low-enough rates of termination that it often exhibits the characteristics of living polymerizations, including molecular weights that increase linearly with conversion and the possibility for chain extension to make block copolymers. These traits enable the synthesis of well-defined polymers using a variety of monomers containing a wide range of functional groups with precise topologies, such as star polymers, − hyperbranched polymers, − single-chain nanoparticles, − polymers with bulky side chains, − and densely grafted bottlebrush (BB) polymers, − among others. However, in particularly challenging polymerizations, including ROMP of monomers with large substituents or synthesis of multiblock copolymers, termination via catalyst decomposition can lead to broader than expected molecular weight distributions and/or mixtures of products.…”

Zinc(ii) phthalocyanine–viologen dyads: synthesis, electrochemistry, spectroelectrochemistry, electrodeposition, and electrochromism

“…2 and 3 were synthesized according to the published procedure. 32,33 All electrochemical and spectroelectrochemical measurements were carried out by following the procedure published in the literature. 34,35 Cyclic voltammetric (CV) and square wave voltammetric (SWV) techniques were employed by using a Gamry Reference 600 Potentiostat/Galvanostat in an electrochemical cell having glassy carbon (GCE), platinum wire and Ag/AgCl working, counter and reference electrodes, respectively in dichloromethane (DCM)/tetrabutylammonium perchlorate (TBAP) electrolyte.…”

“…Compounds 2 and 3 were obtained as described in the literature. 32,33 ZnPc-Br, ZnPc-V, and ZnPc-MV were synthesized as shown in Scheme 1 and Scheme 2.…”