Title : Sol – gel synthesis of silica - poly (vinylpyrrolidone) hybrids with improved antibacterial properties
Abstract:
It is well known that inorganic nanoparticles are highly stable and multifunctional, their biodegradability and biocompatibility have been disputed. Additionally, organic carriers are known for their high biocompatibility and biodegradability, but low stability and single functionality. The advancements in material science catalysed the fabrication of organic?inorganic hybrid nanoparticles which combine desirable properties of organic and inorganic materials to overcome the above mentioned disadvantages. On the other hand, the increasing resistance of human-threatening bacterial strains to traditional antibacterial treatments encourages the consideration of new infection control strategies. The combination of antibiotics and composite nanoparticles multiplies the efficacy of antibiotics against resistant bacteria. In addition, nanoparticle-antibiotic conjugates reduce the amount of both agents in the dosage, which reduces toxicity and increases antimicrobial properties.
The present work deals with sol-gel synthesis of silica - poly (vinylpyrrolidone) hybrid materials. The nanohybrids (Si-PVP) have been prepared using an acidic catalyst at ambient temperature. Tetramethyl ortosilane (TMOS) was used as a silica precursor. Poly (vinylpyrrolidone) (PVP) was introduced into the reaction mixture as a solution in ethanol varying its concentration between 5 and 20 %. The XRD established that the as – prepared materials are amorphous. The gel derived nanopowders were characterized also by SEM, TEM and AFM techniques. The efficacy of Si/PVP nanoparticles as a potential antimicrobial agent against a wide range of bacteria, including those with novel resistance mechanisms using agar diffusion and spot test has been evaluated. Furthermore, we are monitoring the direct bactericidal effects and synergetic effect of the nanoparticles in combination with different antibiotics in liquid media, with the aim of reducing the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Combined therapy can significantly reduce the concentrations of both the antibiotic and the nanocomposites, but also eliminate the antibiotic resistance of the pathogen. These findings suggest that the newly synthesized Si/PVP nanoparticles may be a new, effective and broad-spectrum antibacterial agents, even at lower doses than those currently used in clinical trials to treat bacterial infections.
