[New post] Next Generation Antibacterial Agents: Positively Charged Silver Nanoparticles
Conference Alerts posted: " Nanomaterials are a new paradigm for treating infectious diseases. The unique physicochemical properties of nanoparticles (NPs) enable researchers to design and develop various novel NP-based antimicrobial agents. New research published in the journal Sc"
Nanomaterials are a new paradigm for treating infectious diseases. The unique physicochemical properties of nanoparticles (NPs) enable researchers to design and develop various novel NP-based antimicrobial agents. New research published in the journal Scientific Reports focuses on the influence of size and surface charge of silver nanoparticles (AgNPs) on bactericidal activity.
Antibiotic Resistance and Ag NPs
Hospital-acquired infections (HAIs), majorly from an intensive care unit (ICU), are detrimental to patients' recovery and are mainly associated with multidrug-resistant organisms (MDROs) or antibiotic resistance (AR) in the United States (US).
The antibiotic resistance of gram-negative bacteria is due to the semi permeability of the cell wall to antibiotics. The most common gram-negative bacteria causing HAIs is E. coli. Its virulent strain, E. coli O1:K1:H7 (CN1018), increases its survival due to the expression of adherent fimbriae, causing inflammatogenic responses in a mouse model with urinary tract infection. On the other hand, bacteria lacking the fimbriae showed reduced survival rates in animal models and humans. Thus, antimicrobial agents that target the cell wall, adherent fimbriae, or both are essential.
AgNP is one of the engineered nanomaterials (ENMs) with a range of commercial applications. Nevertheless, previous studies precedented antimicrobial activity by AgNPs, yet their mechanism of action remains unclear.
Influence of Size and Charge on AgNP's Bactericidal Activity
In the present study, the authors employed five nanometers-sized, positively charged amine (NH2)– AgNPs, 45 nanometer-sized negatively charged citrate– AgNPs, and silver ion (Ag+) solution as a control to understand the bactericidal MOA of AgNPs and elucidate the corresponding factors that influence the nano-bio interactions in E. coli.
The authors used this information to compare and determine the potential antimicrobial AgNPs. Further, they documented the potential phenotypic plasticity in E. coli because of Ag treatment. The results revealed that NH2–AgNPs are biocompatible with potent bactericidal effects than citrate–AgNPs.
This study proves the potential of small size, positively charged AgNPs as next-generation antibacterial agents to combat rising HAIs and ensure patient health and safety.
Characterization and Evaluation of Antibacterial Properties of AgNPs
Transmission electron microscopy (TEM) images of NH2–AgNPs revealed that they had a spherical crystalline structure with a diameter of 5.8 ± 2.8 nanometers. The +41.6 millivolts zeta potential was due to the positive amine group functionalization on AgNP's surface. The amine coating of 0.5 to 1.5 nanometers thickness on AgNP's surface enabled their stability via electrostatic repulsion.
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