Despite great efforts, the design of antibacterial surfaces is still a challenge. In this work, results of structural, mechanical, cytotoxic and antibacterial activities of hydrophobic carbon quantum dots/polydimethylsiloxane surfaces are presented. Antibacterial action of this surface is based on the generation of reactive oxygen species which cause bacteria damage by oxidative stress. At the same time, this surface was not cytotoxic towards the NIH/3T3 cells. Swelling-encapsulation-shrink method is applied for encapsulation of hydrophobic carbon quantum dots in medical grade silicone-polydimethylsiloxane. XPS and photoluminescence spectroscopy analyses confirm that hydrophobic carbon quantum dots have been encapsulated successfully into polydimethylsiloxane polymer matrix. Based on stress-strain test the improvement of mechanical properties of these nanocomposites is established. It is shown by electron paramagnetic resonance spectroscopy and luminescence method that nanocomposite generates singlet oxygen initiated by 470 nm blue light irradiation. Antibacterial testing shows the nanocomposite in the form of foil kills Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae and is very effective after only a 15 min irradiation.

Centre of Polymer Systems Tomas Bata University in Zlín Trida Tomase Bati 5678 Zlín Czech Republic

J Heyrovský Institute of Physical Chemistry Academy of Sciences of the Czech Republic Dolejškova 3 182 23 Praha 8 Czech Republic

Polymer Institute Slovak Academy of Sciences Dúbravská cesta 9 84541 Bratislava Slovakia

Vinča Institute of Nuclear Sciences University of Belgrade P O B 522 11001 Belgrade Serbia

Photodiagnosis Photodyn Ther. 2020 Dec;32:101939. doi: 10.1016/j.pdpdt.2020.101939. PubMed

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Highly Efficient Antibacterial Polymer Composites Based on Hydrophobic Riboflavin Carbon Polymerized Dots