Antibacterial activity and cytotoxicity of bioinspired poly (L-DOPA)-mediated silver nanostructure-decorated titanium dioxide nanowires

The combination of silver (Ag) and titanium dioxide (TiO2) nanostructures offer unique advantages in terms of elimination of infection and enhanced antibacterial activity with relatively higher biocompatibility and lower cytotoxicity. Although there have been numerous attempts for the fabrication of these nanocomposite systems, novel, flexible, low-cost, simple, effective, reducing, and stabilizing agent-free strategies are highly required for biomedical applications. Within this context, we report the employment of silver nanostructure decorated TiO2 nanowires (TiO2 NWs) as an ideal antibacterial agent against antibiotic-resistant Gram-negative (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). Firstly, TiO2 NWs were fabricated via the hydrothermal procedure. Afterward, by utilizing the oxidative polymerization of 3,4-dihydroxyphenyl-L-alanine (L-DOPA), a conformal and thin polymer layer of L-DOPA (PLDP) was created onto the TiO2 NWs (TiO2/PLDP). Lastly, Ag nanostructures were deposited onto the TiO2/PLDP (TiO2/PLDP/Ag NP) via simply reduction of silver ions. Herein, PLDP with its abundant catechol and amine groups played an important role in the reduction of silver ions and the adsorption of Ag nanostructures with high affinity and resultant stability. The size, density, and morphology of Ag nanostructures were manipulated by tuning the initial amount of Ag ions in a well-controlled manner. The resultant colloidal TiO2/PLDP/Ag composite nanosystem provided remarkably high and stable antibacterial activity against both antibiotic-resistant bacteria strains. Minimum Inhibitory Concentration (MIC) values were found to be 125, 250, and > 500 ppm for high, medium and, low deposition of Ag nanostructures, respectively. Similarly, Minimum Bactericidal Concentration (MBC) for these NP systems, MBC values were found to be 250, 500, and > 1000 ppm, respectively. Also, relatively lower cytotoxicity in human lung healthy (MRC5) and cancer (A549) cell lines was detected in a dose-dependent manner in comparison to the citrate-stabilized Ag nanoparticles. The proposed novel TiO2/PLDP/Ag nanosystem will provide unique opportunities in terms of flexibility, low-cost, simplicity with reducing, and stabilizing agent-free strategy and be employed in the removal of biofilms and anti-inflammatory effects.

Dergi

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS

Yıl

2022

Cilt

639

ISSN

0927-7757

eISSN

1873-4359

DOI

10.1016/j.colsurfa.2022.128350

WoS UID

WOS:000810781300002