In this work, the antimicrobial activity of neat and silanized titanium dioxide deposited with silver nanoparticles was evaluated when it was used as filler in a poly(lactic acid) matrix. The silanization and deposition processes were evaluated by scanning transmission electron microscopy and X-ray photoelectron spectroscopy confirming the chemical modification on the titanium dioxide surface by 3-aminopropyltriethoxy silane and the formation of silver nanoparticles. According to the elemental analysis conducted by energy-dispersive X-ray spectroscopy, more silver, 7.4% higher, was deposited on the oxide when this was previously silanized and when 30% w/w of silver nitrate was used as a precursor. The antimicrobial effect was confirmed for the nanoparticles through the disk diffusion method and for the composites by drop test, against Staphylococcus aureus and Escherichia coli bacteria; the results showed that the inhibition rate increased by 14.2% and 39.1% for nanoparticles and by 57.6% and 38.8% for composites against each bacteria, respectively, when deposition was performed on silanized titanium dioxide. Also, better mechanical properties were obtained in the composites filled with silanized oxide; the best results were obtained in the PLA/sTiO2–Ag 20% system with an improvement of 45.7% in tensile stress and of 38.73% for Young’s modulus. Finally, the toxicity of the composites was evaluated by seeding peripheral blood mononuclear cells; results show evidence that composites filled with these nanoparticles are non-toxic since these do not migrate from the polymeric matrix, which helps to enhance the prolonged surface antibacterial effect and to open a broad perspective of the commercial use of these composites.
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- Antimicrobial activity
- Poly(lactic acid)
- Polymer composites
- Silver nanoparticles
- Titanium dioxide