Antibacterial activity of cationic polymers: side-chain or main-chain type?

2018 ◽  
Vol 9 (37) ◽  
pp. 4611-4616 ◽  
Author(s):  
Jiangna Guo ◽  
Jing Qin ◽  
Yongyuan Ren ◽  
Bin Wang ◽  
Hengqing Cui ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Small Molecule ◽  
Quaternary Ammonium ◽  
Main Chain ◽  
Side Chain ◽  
Cationic Polymers ◽  
Cationic Compounds ◽  
Chain Type

Imidazolium (Im), quaternary ammonium (Qa), and 1,4-diazabicyclo[2.2.2]octane-1,4-diium (DABCO-diium) cation-based small molecule cationic compounds and their corresponding side-chain/main-chain cationic polymers were synthesized.

scholarly journals Design, Synthesis, Antibacterial, and Antitumor Activity of Linear Polyisocyanide Quaternary Ammonium Salts with Different Structures and Chain Lengths

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5686
Author(s):  
Hongguang Zhang ◽  
Lijia Liu ◽  
Peng Hou ◽  
Jun Liu ◽  
Shuang Fu
Keyword(s):  
Antibacterial Activity ◽  
Quaternary Ammonium ◽  
Main Chain ◽  
Quaternary Ammonium Salts ◽  
Polymer Materials ◽  
Ammonium Salts ◽  
Organic Polymer ◽  
Side Chain ◽  
E Coli ◽  
Chain Lengths

The development of organic polymer materials for disinfection and sterilization is thought of as one of the most promising avenues to solve the growth and spread of harmful microorganisms. Here, a series of linear polyisocyanide quaternary ammonium salts (L-PQASs) with different structures and chain lengths were designed and synthesized by polymerization of phenyl isocyanide monomer containing a 4-chloro-1-butyl side chain followed by quaternary amination salinization. The resultant compounds were characterized by 1H NMR and FT-IR. The antibacterial activity of L-PQASs with different structures and chain lengths against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was evaluated by determining the minimum inhibitory concentrations (MICs). The L-POcQAS-M50 has the strongest antimicrobial activity with MICs of 27 μg/mL against E. coli and 32 μg/mL against S. aureus. When the L-PQASs had the same polymerization degree, the order of the antibacterial activity of the L-PQASs was L-POcQAS-Mn > L-PBuQAS-Mn > L-PBnQAS-Mn > L-PDBQAS-Mn (linear, polyisocyanide quaternary ammonium salt, monomer, n = 50,100). However, when L-PQASs had the same side chain, the antibacterial activity reduced with the increase of the molecular weight of the main chain. These results demonstrated that the antibacterial activity of L-PQASs was dependent on the structure of the main chain and the length of the side chain. In addition, we also found that the L-POcQAS-M50 had a significant killing effect on MK-28 gastric cancer cells.

scholarly journals Side-chain-type anion exchange membranes bearing pendant quaternary ammonium groups via flexible spacers for fuel cells

2016 ◽  
Vol 4 (36) ◽  
pp. 13938-13948 ◽  
Author(s):  
Chen Xiao Lin ◽  
Xiao Ling Huang ◽  
Dong Guo ◽  
Qiu Gen Zhang ◽  
Ai Mei Zhu ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Anion Exchange ◽  
Quaternary Ammonium ◽  
Side Chain ◽  
Anion Exchange Membranes ◽  
Flexible Spacer ◽  
Chain Type

Highly conductive anion exchange membranes can be achieved by tuning the length of flexible spacer between backbone and quaternary ammonium groups.

scholarly journals Physicochemical and Structural Parameters Contributing to the Antibacterial Activity and Efflux Susceptibility of Small Molecule Inhibitors of Escherichia coli

2021 ◽  
Author(s):  
Sara S. El Zahed ◽  
Shawn French ◽  
Maya A. Farha ◽  
Garima Kumar ◽  
Eric D. Brown
Keyword(s):  
Machine Learning ◽  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Small Molecules ◽  
Small Molecule ◽  
In Silico ◽  
Molecular Descriptors ◽  
Structural Parameters ◽  
Side Chain ◽  
Gram Negative

Discovering new Gram-negative antibiotics has been a challenge for decades. This has been largely attributed to a limited understanding of the molecular descriptors governing Gram-negative permeation and efflux evasion. Herein, we address the contribution of efflux using a novel approach that applies multivariate analysis, machine learning, and structure-based clustering to some 4,500 actives from a small molecule screen in efflux-compromised Escherichia coli. We employed principal-component analysis and trained two decision tree-based machine learning models to investigate descriptors contributing to the antibacterial activity and efflux susceptibility of these actives. This approach revealed that the Gram-negative activity of hydrophobic and planar small molecules with low molecular stability is limited to efflux-compromised E. coli. Further, molecules with reduced branching and compactness showed increased susceptibility to efflux. Given these distinct properties that govern efflux, we developed the first machine learning model, called Susceptibility to Efflux Random Forest (SERF), as a tool to analyze the molecular descriptors of small molecules and predict those that could be susceptible to efflux pumps in silico. Here, SERF demonstrated high accuracy in identifying such molecules. Further, we clustered all 4,500 actives based on their core structures and identified distinct clusters highlighting side chain moieties that cause marked changes in efflux susceptibility. In all, our work reveals a role for physicochemical and structural parameters in governing efflux, presents a machine learning tool for rapid in silico analysis of efflux susceptibility, and provides a proof of principle for the potential of exploiting side chain modification to design novel antimicrobials evading efflux pumps.

scholarly journals A comparative study of side-chain-type poly(ether ether ketone) anion exchange membrane functionalized with different hetero-cycloaliphatic quaternary ammonium groups

RSC Advances ◽  
2019 ◽  
Vol 9 (14) ◽  
pp. 7975-7983 ◽  
Author(s):  
Dan Yao ◽  
Tonghui Wei ◽  
Lichao Shang ◽  
Hui Na ◽  
Chengji Zhao
Keyword(s):  
Anion Exchange ◽  
Quaternary Ammonium ◽  
Anion Exchange Membrane ◽  
Side Chain ◽  
Anion Exchange Membranes ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Ether Ketone ◽  
Exchange Membrane ◽  
Chain Type

Anion exchange membranes based on side-chain-type quarternized poly(ether ether ketone)s QPEEKs containing different hetero-cycloaliphatic quaternary ammonium groups were prepared via polycondensation, bromomethylation and quaternization.

Synthesis of a New Water-Soluble Conjugated Polymers Containing Thiazoline Moiety for Antibacterial Activity Bioassay

2013 ◽  
Vol 690-693 ◽  
pp. 1594-1598
Author(s):  
Ji Ping Liu ◽  
Yan Hua Wu ◽  
Lei Liu ◽  
Yu Mei Xiao ◽  
Xiao Dong Ma ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Growth Inhibition ◽  
Conjugated Polymers ◽  
Quaternary Ammonium ◽  
Water Soluble ◽  
Side Chain ◽  
Inhibition Ratio ◽  
Polyfluorene Derivatives

The water-soluble cationic polyfluorene derivatives PFP-N(Me)3+I- and PFP-T containing the thiazoline cycle on side chain was designed and synthesized. The preliminary bioassay was carried out for the thiazolines and polymers at different concentrations. The antibacterial activity of the polymers and thiazolines were determined with E.coli by growth inhibition assays. The results demonstrate that the polymer containing thiazoline cycle (PFP-T) has a higher inhibition ratio against E.coli than the thiazoline compound itself and the corresponding thiazoline quaternary ammonium.

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