Highly Stabilized Nanoparticles on Poly-l-Lysine-Coated Oxidized Metals: A Versatile Platform with Enhanced Antimicrobial Activity

Abstract

The increasing incidence of infections in implantable devices has encouraged the search for biocompatible antimicrobial surfaces. To inhibit the bacterial adhesion and proliferation on biomaterials, several surface functionalization strategies have been developed. However, most of these strategies lead to bacteriostatic effect and only few of these are able to reach the bactericidal condition. In this work, bactericidal surfaces were designed through the functionalization of titanium surfaces with poly-l-lysine (PLL) as the mediator for the incorporation of antimicrobial silver nanoparticles (AgNPs). This functionalization influences the adsorption of the particles on the substrate impeding the agglomeration observed when bare titanium surfaces are used, leading to a homogeneous distribution of AgNPs on the surfaces. The antimicrobial activity of this surface has been tested against two different strains, namely, Staphylococcus aureus and Pseudomonas aeruginosa. For both strains and different AgNPs sizes, the surface modified with PLL and AgNPs shows a much enhanced antimicrobial activity in comparison with AgNPs deposited on bare titanium. This enhanced antibacterial activity is high enough to reach bactericidal effect, a condition hard to achieve in antimicrobial surfaces. Importantly, the designed surfaces are able to decrease the bacterial viability more than 5 orders with respect to the initial bacterial inoculum. That means that a relative low load of AgNPs on the PLL-modified titanium surfaces reaches 99.999% bacterial death after 24 h. The results of the present study are important to avoid infections in indwelling materials by reinforcing the preventive antibiotic therapy usually dosed throughout the surgical procedure and during the postoperative period.

Biocompatibility and photo-induced antibacterial activity of lignin-stabilized noble metal nanoparticles

“…We can recognize the bacteriostatic activity, as less than 3 log 10 reduction in CFU, from the bactericidal activity, where the bacterial viability decrease at least 3 log 10 in CFU. 45,46 Specically, under dark conditions AgNP@alkali show bactericidal activity against E. coli at the MIC (concentration A, Table S2 †) while only bacteriostatic activity is detected at lower Fig. 6 Cell viability measurements (% relative to cell viability in the absence of nanocomposites) carried out by using MTT colorimetric assay (see Experimental section) of human fibroblasts after (A) 1 h incubation with AgNP@lignin nanocomposites and (B) 6 h incubation with AuNP@lignin at the bactericidal concentrations (concentration B for AgNP@alkali and AuNP@lignin, concentration A for AgNP@ZHL and AgNP@AL, according to Table S2 †).…”

Synergistic Antibacterial Activity of Silver-Loaded Graphene Oxide towards Staphylococcus Aureus and Escherichia Coli

“…However, Ag NPs tend to agglomerate and are prone to oxidization, thus limiting the antibacterial effect. For instance, Ag NPs were found to be poorly dispersed in biological solution when grafted onto a titanium or silica substrate [18][19][20][21]. To overcome this problem, combining GO with Ag NPs facilitates the antibacterial properties.…”

Correlation of AFM/SEM/EDS Images to Discriminate Several Nanoparticle Populations Mixed in Cosmetics

“…Here, the substrate charge was modified. Several solutions exist and could be used for this, such as adding polymer chains to the substrate [3][4][5], but at the Laboratoire National de Métrologie et D'essais (LNE) a glow discharge treatment with a specific gas atmosphere (ELMO™, Cordouan Technologies) is used [6,7]. Depending on the gas used, this system can make the substrate hydrophilic or hydrophobic and positively or negatively charged.…”