Cu Nanoparticle-Loaded Nanovesicles with Antibiofilm Properties. Part I: Synthesis of New Hybrid Nanostructures

Abstract

Copper nanoparticles (CuNPs) stabilized by quaternary ammonium salts are well known as antimicrobial agents. The aim of this work was to study the feasibility of the inclusion of CuNPs in nanovesicular systems. Liposomes are nanovesicles (NVs) made with phospholipids and are traditionally used as delivery vehicles because phospholipids favor cellular uptake. Their capacity for hydrophilic/hydrophobic balance and carrier capacity could be advantageous to prepare novel hybrid nanostructures based on metal NPs (Me-NPs). In this work, NVs were loaded with CuNPs, which have been reported to have a biofilm inhibition effect. These hybrid materials could improve the effect of conventional antibacterial agents. CuNPs were electro-synthesized by the sacrificial anode electrolysis technique in organic media and characterized in terms of morphology through transmission electron microscopy (TEM). The NVs were prepared by the thin film hydration method in aqueous media, using phosphatidylcholine (PC) and cholesterol as a membrane stabilizer. The nanohybrid systems were purified to remove non-encapsulated NPs. The size distribution, morphology and stability of the NV systems were studied. Different quaternary ammonium salts in vesicular systems made of PC were tested as stabilizing surfactants for the synthesis and inclusion of CuNPs. The entrapment of charged metal NPs was demonstrated. NPs attached preferably to the membrane, probably due to the attraction of their hydrophobic shell to the phospholipid bilayers. The high affinity between benzyl-dimethyl-hexadecyl-ammonium chloride (BDHAC) and PC allowed us to obtain stable hybrid NVs c.a. 700 nm in diameter. The stability of liposomes increased with NP loading, suggesting a charge-stabilization effect in a novel antibiofilm nanohybrid material.

Green Synthesis and Characterization of Antimicrobial Synergistic AgCl/BAC Nanocolloids

“… 51 , 52 It has been widely used as a stabilizing surfactant of metal NPs aiming at developing a synergistic antibacterial compound. 53 BAC is listed as antibacterial and novel antituberculosis agent by the Johns Hopkins Clinical Compound Library (JHCCL). 54 Apparently, BAC exerts toxic effects on bacteria, and acyl chain length distributions and the degree of C–C saturation of BAC significantly impact on the antimicrobial activity against both Gram-positive and Gram-negative bacteria.…”

Electrodecoration and Characterization of Superparamagnetic Iron Oxide Nanoparticles with Bioactive Synergistic Nanocopper: Magnetic Hyperthermia-Induced Ionic Release for Anti-Biofilm Action

“…When using CuNPs, the chemical reactivity is controlled by the surfactant shell formed during their synthesis, so that these substrates can provide an antibacterial action through the release of metal ions. The total amount of the ion release was demonstrated to be directly related to the amount of copper dispersed in the composite material [ 33 , 35 ], while the kinetics is a function of the chain length of the surfactant and so depending on the thickness of the stabilizing shell [ 52 , 53 ]. Considering the property of iron oxide to have superparamagnetic character and antimicrobial action, a further way to tune copper release from Cu@Fe 3 O 4 by means of magnetic field application has been investigated.…”

“…Based on such an experimental evidence, it can be inferred that supporting core-shell CuNPs on superparamagnetic iron oxide is a valid pathway to specifically tailor SPIONs to ensure a controlled release of copper by application of an alternating magnetic field. Along with the copper loading amount and the nature and thickness of the CuNPs stabilizer shell [ 33 , 35 , 53 ], magnetic hyperthermia proved to be a further and orthogonal way to tune copper ions release, hence the antimicrobial effectiveness modulation can be easily envisaged.…”

Synthesis and characteristics of cross-linked polymer hydrogels with embedded CdS nanocrystals

“…Among them, sol-gel methods for the nanoparticle synthesis under conditions of a restricted crystal growth in polymeric matrices deserve special attention because these methods allow to control the shape, size and size distribution of nanoparticles. To this end, direct and reverse micelles [8], vesicles [9], reverse microemulsions [10], Langmuir-Blodgett films [11], polymer matrices [12,13], polyelectrolite multilayers [14] can be used as nanoreactors for NPs synthesis confining their growth.…”