The Atomic Structure of Ti{sub 2}C and Ti{sub 3}C{sub 2} MXenes is Responsible for Their Antibacterial Activity Toward E. coli Bacteria

• Published in: Journal of materials engineering and performance Vol. 28; no. 3
• Main Authors: Jastrzębska, Agnieszka Maria, Karwowska, Ewa, Wojciechowski, Tomasz, Ziemkowska, Wanda, Rozmysłowska, Anita, Chlubny, Leszek, Olszyna, Andrzej
• Format: Journal Article
• Language: English
• Published: United States 15.03.2019
• Subjects: ATOMS; CHEMICAL ANALYSIS; CHEMICAL COMPOSITION; ESCHERICHIA COLI; MATERIALS SCIENCE; NANOSCIENCE AND NANOTECHNOLOGY; SCANNING ELECTRON MICROSCOPY; TRANSMISSION ELECTRON MICROSCOPY; X-RAY PHOTOELECTRON SPECTROSCOPY
• ISSN: 1059-9495; 1544-1024

The expanded Ti{sub 2}C and Ti{sub 3}C{sub 2} MXene phases were synthesized from their parent Ti{sub 2}AlC and Ti{sub 3}AlC{sub 2} MAX phases using the same conditions of the classical acidic aluminum extraction method. The assumption for the study was that the expanded Ti{sub 2}C and Ti{sub 3}C{sub 2} MXenes are composed of the same atoms and if are synthesized from MAX phases using the same conditions of the classical acidic aluminum extraction method, the observed bio-effects can be related only to the changes in their structures. The scanning electron microscope investigations indicated that the expanded Ti{sub 2}C and Ti{sub 3}C{sub 2} sheets formed the specific network of slit-shaped nano-pores. The x-ray photoelectron spectroscopy for chemical analysis (ESCA-XPS) showed almost no difference in surface chemistry of Ti{sub 2}C and Ti{sub 3}C{sub 2} MXenes. The high-resolution transmission electron microscope investigations revealed, however, differences in atomic structure of the individual Ti{sub 2}C and Ti{sub 3}C{sub 2} sheets. Measured distance between Ti-C atomic layers in Ti{sub 2}C was 9.76 Å and was larger by 0.53 Å in comparison with Ti{sub 3}C{sub 2} (9.23 Å). Our investigations of bioactive properties toward model gram-negative Escherichia coli bacterial strain showed that the Ti{sub 2}C MXene did not influence the viability of bacteria. Contrarily, the Ti{sub 3}C{sub 2} MXene showed antibacterial properties. The results of the study indicate that the structure at the atomic scale may play a key role in the bioactivity of MXenes of the same chemical composition, but different stoichiometry, just like in case of Ti{sub 2}C and Ti{sub 3}C{sub 2}.