Controlled killing of human cervical cancer cells by combined action of blue light and C-doped TiO2 nanoparticles

Abstract

In this study, C-doped TiO 2 nanoparticles (C-TiO 2 ) were prepared and tested as a photosensitizer for visible-light-driven photodynamic therapy against cervical cancer cells (HeLa). X-ray diffraction and Transmission Electron Microscopy confirmed the anatase form of nanoparticles, spherical shape, and size distribution from 5 to 15 nm. Ultraviolet-visible light spectroscopy showed that C doping of TiO 2 enhances the optical absorption in the visible light range caused by a bandgap narrowing. The photo-cytotoxic activity of C-TiO 2 was investigated in vitro against HeLa cells. The lack of dark cytotoxicity indicates good biocompatibility of C-TiO 2 . In contrast, a combination with blue light significantly reduced the survival of HeLa cells: illumination only decreased cell viability by 30% (15 min of illumination, 120 µW power), and 60% when HeLa cells were preincubated with C-TiO 2 . We have also confirmed blue light-induced C-TiO 2 -catalyzed generation of reactive oxygen species in vitro and intracellularly. Oxidative stress triggered by C-TiO 2 /blue light was the leading cause of HeLa cell death. Fluorescent labeling of treated HeLa cells showed distinct morphological changes after the C-TiO 2 /blue light treatment. Unlike blue light illumination, which caused the appearance of large necrotic cells with deformed nuclei, cytoplasm swelling, and membrane blebbing, a combination of C-TiO 2 /blue light leads to controlled cell death, thus providing a better outcome of local anticancer therapy.

Defect Engineering in Biomedical Sciences

“…[ 23,25,51,52 ] Doped TiO 2 is a typical success story. Researchers have successfully prepared TiO 2 doped with anions such as C [ 53,54 ] and N, [ 55 ] as well as TiO 2 doped with metal cations such as Fe, [ 56 ] V, [ 57 ] W, [ 58 ] Mn, [ 59 ] and rare earth metals. [ 60 ] Although both anion doping and cation doping could reduce the bandgap of TiO 2 , the specific effects were different.…”

“…synthesized C‐doped TiO 2 by hydrothermal reaction at 160 °C for 12 h by mixing TiO 2 precursor with glucose solution (providing a C source). [ 54 ]…”

“…[55] Nešić et al synthesized C-doped TiO 2 by hydrothermal reaction at 160 °C for 12 h by mixing TiO 2 precursor with glucose solution (providing a C source). [54] Single Atom: There are many ways to introduce single-atom defects into pre-synthesized nanomaterials. For example, He et al designed defect-rich titanium carbide MXene (Ti 3 C 2 ) with Ti vacancies by etching.…”

Effective CO2 Capture and Selective Photocatalytic Conversion into CH3OH by Hierarchical Nanostructured GO–TiO2–Ag2O and GO–TiO2–Ag2O–Arg

“…The rapid recombination of the e – /h + pair is disadvantageous to the whole process and limits the photocatalytic efficiency. − A number of semiconductor photocatalysts have been widely used for the reduction of CO 2 into fuels, such as TiO 2 , CdS, ZnO, and In 2 O 3 . Among them, TiO 2 has attracted a lot of attention as a photocatalyst due to its lower cost. − Nonetheless, TiO 2 exhibits weak performance due to the fast electron/hole (e – /h + ) pair recombination rate and large band gap energy, being active only under UV light irradiations, disadvantages that need to be overcome to become an active photocatalyst. ,− To overcome some of these limitations, different approaches can be considered such as (i) adding a sacrificial agent, (ii) depositing metallic nanoparticles, or (iii) the use of semiconductors with a narrow band gap. − Due to their higher absorption rate, lower toxicity, and higher stability, amines have been used, as a sacrificial electron donor, in the field of artificial photosynthesis by researchers from the 1970s to the present day. , The use of sacrificial amines allows the photoreduction of CO 2 to take place, when the position of the valence band (VB) of the photocatalysts is negative compared to the standard oxidation potential of H 2 O, and at the same time accelerates the separation rates of the electron–hole pairs and therefore improves the photoreduction of CO 2 . − Graphene oxide (GO) is another very favorable option in the photocatalytic field, which contributes to the effective degradation of CO 2 . The excellent absorption and conductivity capacity of GO in combination with TiO 2 can be considered a versatile composite for photocatalysts. ,− Considering the above-mentioned facts, in our study, we developed a photocatalytic system based on titanium dioxide (TiO 2 ) associated with GO, using arginine as a sacrificial agent.…”

Effective CO2 Capture and Selective Photocatalytic Conversion into CH3OH by Hierarchical Nanostructured Photocatalysts GO-TiO2-Ag2O and GO-TiO2-Ag2O-Arg

“…Among them, TiO2 has attracted a lot of attention as a photocatalyst lower cost [10][11][12][13][14][15] . Nonetheless, TiO2 has low performance due to the fast electron/hole (e -/h + ) pair recombination rate, and large bandgap energy being active only under UV-light irradiations, disadvantages that need to be overcome to become an active photocatalyst 9,[16][17][18][19][20] . To overcome some of these limitations, different approaches can be considered such as (i) adding a sacrificial agent, (ii) depositing metallic nanoparticles (iii), or the use of semiconductors with narrow bandgap [21][22][23][24] .…”