Abstract
Introduction
The silver/graphitic carbon nitride (Ag/g-C3N4) composite system exerts biocidal activity against the pathogenic bacterium Escherichia coli 1337-H that is stronger than that of well-known silver and titanium oxide (TiO2)-based composites. However, whether the Ag/g-C3N4 composite system has biocidal properties that the parent components do or do not have as separate chemical entities and whether they differ from those in Ag/TiO2 composite photocatalysts have not been clarified.
Objective
We investigated the chemical (cooperative charge handling and electronic properties) and biological (metabolic) effects exerted by the addition of Ag to g-C3N4 and to TiO2.
Methods
In this work, we undertook metabolome-wide analysis by liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry to compare the metabolite profiles of untreated E. coli 1337-H cells or those subjected to disinfection with Ag, g-C3N4, 2Ag/g-C3N4, TiO2 and 2Ag/TiO2.
Results
While Ag or g-C3N4 moderately affected microbial metabolism according to the mean of the altered metabolites, multiple cell systems contributing to rapid cell death were immediately affected by the light-triggered radical species produced when Ag and g-C3N4 were as xAg/g-C3N4. The effects include drastically reduced production of small metabolites essential for detoxifying reactive oxygen species and those that regulate DNA replication fidelity, cell morphology and energy status. These biological consequences were different from those caused by Ag/TiO2-based biocides, demonstrating the uniqueness of the Ag/g-C3N4 system.
Conclusions
Our results support the idea that the unique Ag/g-C3N4 biocidal properties are based on synergistic action and reveal new directions for designing future photocatalysts for use in disinfection and microbial control.
Graphical abstract

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Data availability
The mass spectrometry metabolomics data were deposited in the MetaboLights repository with the dataset identifier MTBLS1771 (www.ebi.ac.uk/metabolights/MTBLS1771).
References
Aubron, C., Glodt, J., Matar, C., Huet, O., Borderie, D., Dobrindt, U., et al. (2012). Variation in endogenous oxidative stress in Escherichia coli natural isolates during growth in urine. BMC Microbiology, 12, 120. https://doi.org/10.1186/1471-2180-12-120
Birben, E., Sahiner, U. M., Sackesen, C., Erzurum, S., & Kalayci, O. (2012). Oxidative stress and antioxidant defense. World Allergy Organization Journal, 5, 9–19. https://doi.org/10.1097/WOX.0b013e3182439613
Cruz-Ortíz, B., Hamilton, J. W. J., Pablos, C., Díza-Jiménez, C., Cortés-Hernández, D. A., Sharma, P. K., et al. (2017). Mechanism of photocatalytic disinfection using titania-graphene composites under UV and visible irradiation. Chemical Engineering Journal, 316, 179–186. https://doi.org/10.1016/j.cej.2017.01.094
Endo, M., Wei, Z., Wang, K., Karabiyik, B., Yoshiiri, K., Rokicka, P., et al. (2018). Noble metal-modified titania with visible-light activity for the decomposition of microorganisms. Beilstein Journal of Nanotechnology, 9, 829–841. https://doi.org/10.3762/bjnano.9.77
Ferrer, M., Raczkowska, B. A., Martínez-Martínez, M., Barbas, C., & Rojo, D. (2017). Phenotyping of gut microbiota: Focus on capillary electrophoresis. Electrophoresis, 38, 2275–2286.
Foster, H. A., Ditta, I. B., Varghese, S., & Steele, A. (2011). Photocatalytic disinfection using titanium dioxide: spectrum and mechanism of antimicrobial activity. Applied Microbiology and Biotechnology, 90, 1847–1868. https://doi.org/10.1007/s00253-011-3213-7
Godzien, J., Alonso-Herranz, V., Barbas, C., & Armitage, E. C. (2015). Controlling the quality of metabolomics data: new strategies to get the best out of the QC sample. Metabolomics, 11, 518–528. https://doi.org/10.1007/s11306-014-0712-4
Gogniat, G., & Dukan, S. (2007). TiO2 photocatalysis causes DNA damage via fenton reaction-generated hydroxyl radicals during the recovery period. Applied and Environmental Microbiology, 73, 7740–7743. https://doi.org/10.1128/AEM.01079-07
González-Riano, C., Dudzik, D., Garcia, A., Gil-de-la-Fuente, A., Gradillas, A., Godzien, J., López-Gonzálvez, Á., Rey-Stolle, F., Rojo, D., Ruperez, F. J., Saiz, J., & Barbas, C. (2020). Recent Developments along the analytical process for metabolomics workflows. Analytical Chemistry, 92, 203–226. https://doi.org/10.1021/acs.analchem.9b04553
Guo, A. C., Jewison, T., Wilson, M., Liu, Y., Knox, C., Djoumbou, Y., et al. (2013). ECMDB: The E. coli metabolome database. Nucleic Acids Research. https://doi.org/10.1093/nar/gks992
Guo, J. R., Li, Z., Wang, C. Y., Kei Lam, C. W., Chen, Q. Q., Zhang, W. J., et al. (2017). Profiling of ribonucleotides and deoxyribonucleotides pools in response to DNA damage and repair induced by methyl methanesulfonate in cancer and normal cells. Oncotarget, 8, 101707–101719.
Haug, K., Cochrane, K., Nainala, V. C., Williams, M., Chang, J., Jayaseelan, K. V., & O’Donovan, C. (2020). MetaboLights: A resource evolving in response to the needs of its scientific community. Nucleic Acids Research, 48, D440–D444. https://doi.org/10.1093/nar/gkz1019
Hu, C., Guo, J., Qu, J., & Hu, X. (2007). Photocatalytic degradation of pathogenic bacteria with AgI/TiO2 under visible light irradiation. Langmuir, 9, 4982–4987. https://doi.org/10.1021/la063626x
Kapoore, R. V., & Vaidyanathan, S. (2016). Towards quantitative mass spectrometry-based metabolomics in microbial and mammalian systems. Philosophical Transactions of the Royal Society A, 374, 20150363. https://doi.org/10.1098/rsta.2015.0363
Kiwi, J., & Nadtochenko, V. (2005). Evidence for the mechanism of photocatalytic degradation of the bacterial wall membrane at the TiO2 interface by ATR-FTIR and laser kinetic spectroscopy. Langmuir, 21, 4631–4641. https://doi.org/10.1021/la046983l
Kubacka, A., Ferrer, M., Martínez-Arias, A., & Fernández García, M. (2008). Ag promotion of TiO2-anatase disinfection capability: study of Escherichia coli inactivation. Applied Catalysis B: Environmental, 84, 87–93. https://doi.org/10.1016/j.apcatb.2008.02.020
Kubacka, A., Muñoz-Batista, M. J., Ferrer, M., & Fernández-García, M. (2013). UV and visible light optimization of anatase TiO2 antimicrobial properties: Surface deposition of metal and oxide (Cu, Zn, Ag) species. Applied Catalysis B: Environmental, 140–141, 680–690. https://doi.org/10.1016/j.apcatb.2013.04.077
Kubacka, A., Muñoz-Batista, M. J., Ferrer, M., & Fernández-Garcia, M. (2018). Er-W codoping of TiO2-anatase: Structural and electronic characterization and disinfection capability under UV–vis, and near-IR excitation. Applied Catalysis B: Environmental, 228, 113–129. https://doi.org/10.1016/j.apcatb.2018.01.064
Kubacka, A., Suárez-Díaz, M., Rojo, D., Bargiela, R., Ciordia, S., Zapico, I., et al. (2014). Understanding the antimicrobial mechanism of TiO2-based nanocomposite films in a pathogenic bacterium. Scientific Reports, 4, 4134–4142. https://doi.org/10.1038/srep04134
Ledesma-Amaro, R., Buey, R. M., & Revuelta, J. L. (2015). Increased production of inosine and guanosine by means of metabolic engineering of the purine pathway in Ashbya gossypii. Microbial Cell Factories, 14, 58. https://doi.org/10.1186/s12934-015-0234-4
Leonardi, R., & Jackowski, S. (2007). Biosynthesis of Pantothenic Acid and Coenzyme A. EcoSal plus. https://doi.org/10.1128/ecosalplus.3.6.3.4
Leung, Y. H., Xu, X., Ma, A. P. Y., Liu, F., Ng, A. M. C., Shen, Z., et al. (2016). Leung, Toxicity of ZnO and TiO2 to Escherichia coli cells. Scientific Reports, 6, 35243. https://doi.org/10.1038/srep35243
Li, P., Li, J., Feng, X., Li, J., Hao, Y., Zhang, J., et al. (2019). Metal-organic frameworks with photocatalytic bactericidal activity for integrated air cleaning. Nature Communications, 10, 2177. https://doi.org/10.1038/s41467-019-10218-9
Liang, J. Y., Cheng, C. W., Yu, C. H., & Chen, L. Y. (2015). Investigations of blue light-induced reactive oxygen species from flavin mononucleotide on inactivation of E. coli. The Journal of Photochemistry and Photobiology B, 143, 82–88. https://doi.org/10.1016/j.jphotobiol.2015.01.005
Liebeke, M., Dörries, K., Meyer, H., & Lalk, M. (2012). Metabolome analysis of gram-positive bacteria such as Staphylococcus aureus by GC-MS and LC-MS. Methods in Molecular Biology, 815, 377–398. https://doi.org/10.1007/978-1-61779-424-7_28
Lok, C.-N., Ho, C.-M., Chen, R., He, Q.-Y., Yu, W.-Y., Sun, H., et al. (2006). Proteomic analysis of the mode of antibacterial action of silver nanoparticles. Journal of Proteome Research, 5, 916–924. https://doi.org/10.1021/pr0504079
Mamba, G., & Mishra, A. K. (2016). Graphitic carbon nitride (g-C3N4) nanocomposites: A new and exciting generation of visible light driven photocatalysts for environmental pollution remediation. Applied Catalysis B: Environmental, 198, 347–377. https://doi.org/10.1016/j.apcatb.2016.05.052
Matsumaga, T., Tomada, R., Nakajima, T., & Wake, H. (1985). Photoelectrochemical sterilization of microbial cells by semiconductor powders. FEBS Microbiology Letters, 29, 211–214. https://doi.org/10.1111/j.1574-6968.1985.tb00864.x
Morollo, A. A., & Bauerle, R. (1993). Characterization of composite aminodeoxyisochorismate synthase and aminodeoxyisochorismate lyase activities of anthranilate synthase. Proceedings of the National Academy of Sciences of the United States of America, 90, 9983–9987. https://doi.org/10.1073/pnas.90.21.9983
Moya, A., & Ferrer, M. (2016). Functional redundancy-induced stability of gut microbiota subjected to disturbance. Trends in Microbiology, 24, 402–413. https://doi.org/10.1016/j.tim.2016.02.002
Muñoz-Batista, M. J., Ferrer, M., Fernández-García, M., & Kubacka, A. (2014). Abatement of organics and Escherichia coli using CeO2-TiO2 composite oxides: Ultraviolet and visible light performances. Applied Catalysis B: Environmental, 154–155, 350–359. https://doi.org/10.1016/j.apcatb.2014.02.038
Muñoz-Batista, M. J., Fontelles-Carceller, O., Ferrer, M., Fernández-García, M., & Kubacka, A. (2016). Disinfection capability of Ag/g-C3N4 composite photocatalysts under UV and visible light illumination. Applied Catalysis B: Environmental, 183, 86–95. https://doi.org/10.1016/j.apcatb.2015.10.024
Murugesan, P., Moses, J. A., & Anandharamakrishnan, C. (2019). Photocatalytic disinfection efficiency of 2D structure graphitic carbon nitride-based nanocomposites: a review. Journal of Materials Science, 54, 12206–12235. https://doi.org/10.1007/s10853-019-03695-2
Nosaka, Y., & Nosaka, A. Y. (2017). Generation and detection of reactive oxygen species in photocatalysis. Chemical Reviews, 117, 11302–11336. https://doi.org/10.1021/acs.chemrev.7b00161
Rojo, D., Gosalbes, M. J., Ferrari, R., Pérez-Cobas, A. E., Hernández, E., Oltra, R., Buesa, J., Latorre, A., Barbas, C., Ferrer, M., & Moya, A. (2015). Clostridium difficile heterogeneously impacts intestinal community architecture but drives stable metabolome responses. The ISME Journal, 9, 2206–2220. https://doi.org/10.1038/ismej.2015.32
Schwarz-Linek, J., Arlt, J., Jepson, A., Dawson, A., Vissers, T., Dario Miroli, T., et al. (2016). Escherichia coli as a model active colloid: A practical introduction. Colloids and Surfaces B: Biointerfaces, 137, 2–16. https://doi.org/10.1016/j.colsurfb.2015.07.048
Wang, W., Huang, G., Yu, J. C., & Wong, P. K. (2015). Advances in photocatalytic disinfection of bacteria: development of photocatalysts and mechanisms. Journal of Environmental Sciences (china), 34, 232–247. https://doi.org/10.1016/j.jes.2015.05.003
Xu, J., Wang, Z., & Zhu, Y. (2017). Enhanced visible-light-driven photocatalytic disinfection performance and organic pollutant degradation activity of porous g-C3N4 nanosheets. ACS Applied Materials & Interfaces, 9, 27727–27735. https://doi.org/10.1021/acsami.7b07657
Zaritsky, A., Woldringh, C. L., Einav, M., & Alexeeva, S. (2006). Use of thymine limitation and thymine starvation to study bacterial physiology and cytology. Journal of Bacteriology, 188, 1667–1679. https://doi.org/10.1128/JB.188.5.1667-1679.2006
Zhang, C., Li, Y., Shuai, D., Shen, Y., Xiong, W., & Wang, L. (2019). Graphitic carbon nitride (g-C3N4)-based photocatalysts for water disinfection and microbial control: A review. Chemosphere, 214, 462–479. https://doi.org/10.1016/j.chemosphere.2018.09.137
Funding
Financial support by Fundación General CSIC (programa ComFuturo) and AEI (PID2019-105490RB-C31) is acknowledged. C.B. and D.R. acknowledge funding from the Ministry of Science, Innovation and Universities (RTI2018-095166-B-I00).
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AK, MF-G and MF designed the study. AK, MJM-B and MF-G prepared the nanocomposites and performed the photocatalytic activity and radical species determination analyses; AK and MF performed disinfection tests and metabolite extractions. DR and CB performed metabolomics analyses. MF and DR analysed the metabolomics data. MF, MF-G and AK wrote the first version of the manuscript, which was revised and approved by all coauthors.
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Kubacka, A., Rojo, D., Muñoz-Batista, M.J. et al. Metabolomics reveals synergy between Ag and g-C3N4 in Ag/g-C3N4 composite photocatalysts: a unique feature among Ag-doped biocidal materials. Metabolomics 17, 53 (2021). https://doi.org/10.1007/s11306-021-01804-4
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DOI: https://doi.org/10.1007/s11306-021-01804-4