Preparation of Silver-Doped Alumina Spherical Beads with Antimicrobial Properties

Abstract

The synthesis of composites with antibacterial properties is of great interest for the development of new biomedical applications. The antimicrobial properties of silver have been verified against microorganisms such as bacteria, viruses, and fungi; interest in silver has been renewed, so several technologies are currently in development, especially in dental materials. The purpose of this work was to improve the parameters for producing silver-doped alumina spherical beads using sodium alginate as a sacrificial template. Alumina is a biocompatible and thermally stable ceramic, while silver was used for its bactericidal properties. The obtained spheres presented a mean diameter of 2 mm, with an irregular surface and intertwined particles after a sintering process. After electrodeposition, white spheres turned to a dark gray color, demonstrating the presence of silver nanoparticles and fractal silver dendrites on the surface. Spheres were characterized by SEM, FTIR, and XRD. Antimicrobial activity of the alumina-AgP spheres against E. coli, S. aureus, K. pneumoniae, and S. mutans was analyzed by turbidimetry. The specific antimicrobial activity of all the composites showed specific antibacterial effects, independently of the amount of silver deposited, probably due to the differences in the microbial cell wall structures. Therefore, antibacterial activity depends on microbiological and structural characteristics of each bacterium.

Antimicrobial and Substantivity Properties of Silver Nanoparticles against Oral Microbiomes Clinically Isolated from Young and Young-Adult Patients

“…The dental plaque biofilm samples were obtained using similar criteria than the sample collection, oral biofilm sampling, and bacterial suspension sections. The substantivity assay was made according to parameters previously reported with some modifications [37]. 20 μL of each antimicrobial sample (AgNPs, chlorhexidine, and deionized water) and 100 μL of a standardized suspension (1:3 × 10 8 CFU/mL) of dental plaque biofilm previously taken were added to sterilized tubes containing 4 mL of MH broth with 2% sucrose.…”

Synthesis of Hydroxyapatite-Ag Composite as Antimicrobial Agent

“…10 Therefore, silver containing in HAp composite fusing biocompatibility, great bioactivity, osteoconductive and chemical stability of HAp with the antibacterial effect of Ag to give a great potential application in bone substitute materials or in coating metal implants to prevent implant-related infections. [11][12][13][14][15][16][17][18] There are several methodologies available for the synthesis of silver nanoparticles: reduction in aqueous systems, chemical reactions, photochemical, thermal decomposition of silver compounds, radiation, electrochemical, sonochemical, microwave chemical routes and recently green methodologies. [9][10][11][12][13][14][15][16][17][18][19] Green synthesis methodologies of synthesis of silver nanoparticles have proven to be better practices, allow manipulation, control overgrowth and stabilization, allowing application in nanomedicine, avoiding the use of toxic products in the synthesis protocol.…”

“…Silver nanoparticles were effective in killing a wide variety of bacterial pathogens involved in nosocomial infections such as Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, Klebsiella oxytoca and Escherichia coli . 1 - 12 The mechanism that has been reported is through the damage caused by Ag + ions to the cell membranes of bacteria. The antibacterial efficacy of AgNPs is also known to depend on size, shape, dose, and time.…”

“… 6 - 12 Triangular silver nanoparticles exhibit a better bactericidal effect than spherical and rod-shaped AgNPs, due to the high reactivity to silver in the basal plane (111), the reactivity of this plane has been reported for dendritic growth and formation of hot spots. 12 Ceramic–metal nanocomposites appear to expand the applications of biocide metals. Proteins, amino acids, and organic substances are easily adsorbed on the HAp surface, which in turn promotes the adsorption and replication of the bacteria on the HAp and consequently induces implant-related infections.…”

Bionanotechnology: Silver Nanoparticles Supported on Bovine Bone Powder Used as Bactericide

“…This organism was proposed because it is one of the most difficult to treat, being the cause of severe diarrhea due to consumption of water contaminated with coliforms. This type of bacteria has become multi-resistant to antibiotics, making its treatment rather difficult and is an important cause of death in places where people do not have access to drinking water [4,[9][10][11][12][13][14][15][16][17]].…”