Branched Poly(ethylene imine)s as Anti‐algal and Anti‐cyanobacterial Agents with Selective Flocculation Behavior to Cyanobacteria over Algae

Abstract

Poly(ethylene imine)s (PEIs) have been widely studied for biomedical applications, including antimicrobial agents against potential human pathogens. The interactions of branched PEIs (B-PEIs) with environmentally relevant microorganisms whose uncontrolled growth in natural or engineered environments causes health, economic, and technical issues in many sectors of water management are studied. B-PEIs are shown to be potent antimicrobials effective in controlling the growth of environmentally relevant algae and cyanobacteria with dual-functionality and selectivity. Not only did they effectively inhibit growth of both algae and cyanobacteria, mostly without causing cell death (static activity), but they also selectively flocculated cyanobacteria over algae. Thus, unmodified B-PEIs provide a cost-effective and chemically facile framework for the further development of effective and selective antimicrobial agents useful for control of growth and separation of algae and cyanobacteria in natural or engineered environments.

Biomimetic antimicrobial polymers—Design, characterization, antimicrobial, and novel applications

“…Only N‐halamine‐derivatized PAM nanoparticles exhibited selectivity to cyanobacteria over algae, likely by a preferential attachment to cyanobacterial cell surfaces (Sadhasivam et al, 2019). Finally, some polymers induced cyanobacterial [PEIs (Arrington et al, 2003; Mikula et al, 2018; Zeleznik et al, 2002), PPI‐DEN (Mikula et al, 2018), PDADMAC‐PSFA (Lv et al, 2018)] or algicidal [PAMAM dendrimers (Perreault et al, 2012), core–shell polystyrene–copper oxide nanoparticles (Saison et al, 2010)] cell aggregation (flocculation, illustration in Figure 2). Branched PEIs with MW 12 or 1.1 kDa aggregated selectively cyanobacterial over algal cells (Mikula et al, 2018).…”

“…Finally, some polymers induced cyanobacterial [PEIs (Arrington et al, 2003; Mikula et al, 2018; Zeleznik et al, 2002), PPI‐DEN (Mikula et al, 2018), PDADMAC‐PSFA (Lv et al, 2018)] or algicidal [PAMAM dendrimers (Perreault et al, 2012), core–shell polystyrene–copper oxide nanoparticles (Saison et al, 2010)] cell aggregation (flocculation, illustration in Figure 2). Branched PEIs with MW 12 or 1.1 kDa aggregated selectively cyanobacterial over algal cells (Mikula et al, 2018). Specifically, they effectively flocculated S .…”

Polytrimethylenimines: Highly Potent Antibacterial Agents with Activity and Toxicity Modulated by the Polymer Molecular Weight

“…13 Studies also show that they are able to improve bacterial susceptibility for β-lactam antibiotics. 15 Derivatives of PEI have been extensively studied as antimicrobial agents, 16,17 as nonviral transfection vectors, 18,19 and for other biomedical applications. 19,20 The results, however, have shown that the polymer exhibits relatively high cytotoxicity, which limits its applications to nonmedical uses such as antibacterial coatings or paints.…”

“…Derivatives of PEI have been extensively studied as antimicrobial agents, , as nonviral transfection vectors, , and for other biomedical applications. , The results, however, have shown that the polymer exhibits relatively high cytotoxicity, which limits its applications to nonmedical uses such as antibacterial coatings or paints. , On the other hand, polytrimethylenimine (PTMI), an analogue of PEI with a three-methylene spacer between amine groups, has received substantially lower attention. Its dendrimeric form has gained popularity as a nonviral transfection vector and in drug delivery systems, , although there are very limited reports on a linear form of PTMI. − Different N -methylated PTMI derivatives were synthesized; ,, however, they have not been the subject of antimicrobial studies.…”

Beyond Amphiphilic Balance: Changing Subunit Stereochemistry Alters the Pore-Forming Activity of Nylon-3 Polymers

“…Common features among AMPs have inspired the design of antibacterial polymers with a wide range of backbones and appended functionality. ,,− Positive charges have typically been incorporated into side chains via protonated or quaternized nitrogen-based groups (amines or guanidines) or quaternized phosphorus; charged groups have also been incorporated directly into the backbone. ,− Hydrophobicity has been incorporated via both side chains and the backbone. − By combining hydrophobic and cationic groups in individual subunits or by mixing cationic and hydrophobic subunits, one can achieve the amphiphilicity necessary for an AMP-mimetic activity profile. The importance of maintaining balance between hydrophobic and cationic groups (“amphiphilic balance”) in antimicrobial polymer design, to ensure specificity toward prokaryotes, has been widely noted. , Excessive hydrophobicity can lead to disruption of eukaryotic cell membranes, a trend that is manifested also among synthetic peptides and peptide mimics (such as peptoids) inspired by AMPs. − …”