## 5 Conclusions  
In this paper, we compared the antibacterial and antibofouling activities of two types of polymer composite films: CPDs/PU and C\({}_{60}\)/PU. CPDs were synthesized using the solvothermal method using cheap riboflavin powder as a precursor. AFM analysis showed that these dots had a core-shell structure. CPDs and C\({}_{60}\) were encapsulated into polyurethane films using the swelling-encapsulation-shrink method. EFM analysis indicated that the electronic structure of the CPD/PU and C\({}_{60}\)/PU composite films was related to their ROS generation and antibacterial properties. Both polymer composite films produced ROS: CPD/PU composite films generated both singlet oxygen and hydroxyl radicals, whereas C\({}_{60}\)/PU composite films generated singlet oxygen only. Antibacterial testing showed strong activity of these composite films against seven bacteria strains and one fungus. The antibofouling activity of the CPD/PU composite films showed almost full eradication of biofilms of _P. aeruginosa_ and _S. aureus_ under blue light irradiation for 1 h. In this way, both polymer composite films could have a promising future as antibacterial surfaces in hospitals, especially in intensive care and burn units.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/jfb15030073/s1](https://www.mdpi.com/article/10.3390/jfb15030073/s1)]([https://www.mdpi.com/article/10.3390/jfb15030073/s1](https://www.mdpi.com/article/10.3390/jfb15030073/s1)); Figure S1: (a) FTIR spectra of C\({}_{60}\) (black curve) and CPDs (red curve) and (b) FTIR spectra of neat PU (black curve), CPDs/PU (red curve) and C\({}_{60}\)/PU (green curve). All spectra are displaced for clarity, Figure S2: (a) UV-Vis spectra of C\({}_{60}\) (black curve) and CPDs (red curve) and (b) UV-Vis spectra of C\({}_{60}\)/PU (black curve) and CPDs/PU (red curve) composite films. All UV-Vis spectra were normalized to 1. Table S1: Position of characteristic bonds and shifts (\(\Delta\)) identified in all samples in cm\({}^{-1}\).  
Conceptualization, B.M.T.M. and Z.M.M.; methodology, Z.M.M., M.D.B.F., D.D.M., J.K. and B.M.T.M.; software, Z.M.M. and B.M.T.M.; validation, B.M.T.M., M.D.B.F. and Z.M.M.; formal analysis, Z.M.M. and J.K.; investigation, B.M.T.M. and Z.M.M.; resources, B.M.T.M.; data curation, Z.M.M., M.D.B.F., D.D.M., J.K. and B.M.T.M.; writing--original draft preparation, Z.M.M. and B.M.T.M.; writing--review and editing, B.M.T.M.; visualization, Z.M.M.; supervision, B.M.T.M.; project administration, B.M.T.M.; funding acquisition, B.M.T.M. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the Science Fund of the Republic of Serbia (grant no. #7741955, Are photoactive nanoparticles salvation the global infection threat? PHOTOGUN4 MICROBES). This research was also supported by the Ministry of Science, Technological Development and Innovation of the Republic of Serbia (grant number 451-03-66/2024-03/200017). The authors acknowledge the financial support from the Slovenian Research Agency (research core funding no. P2-0082).  
The data presented in this study are available on request from the corresponding author.  
Special thanks to [PERSON] from The Institute of Virology, Vaccines and Sera \"Torlak\", who performed antibacterial testing of both types of composites.  
The authors declare no conflicts of interest.