## 2 Metallic Nanoparticles in Conjugation with Chlorin Derivatives
### Other Metallic Nanoparticles
The highest potential with IC\({}_{50}\) values equal to 5.1 and 6.0 \(\upmu\)M for CT29 and HT29 cells, respectively, was observed after the use of chlorin-bearing nanosheets. Similarly, in the trials based on subcutaneous flank tumor mouse models of CT29 and HT29, the chlorin-based nanosheets presented the highest activity and caused significant tumor regression [57]. [PERSON] et al. designed a multifunctional nanoparticle system for PDT and PTT, allowing for an increase in the partial concentration of molecular oxygen within tumor tissue [58]. It is well-known that endogenous hydrogen peroxide is present in the tumor at a reasonable concentration of up to 10\({}^{-3}\) M, whereas molecular oxygen is present at a low level, causing hypoxia [59]. Therefore, the platinum nanoparticles responsible for the conversion of H\({}_{2}\)O\({}_{2}\) to molecular O\({}_{2}\) were introduced to the bioactive material. Thanks to the production of oxygen atoms within cancerous tissue, Ce6 formed singlet oxygen efficiently. Platinum nanoparticles were encapsulated in UiO-66-NH\({}_{2}\)--an organic framework formed by [Zr\({}_{6}\)O\({}_{4}\)(OH)\({}_{4}\)] clusters with 1,4-benzodicarboxy acid spacers, which was also coated with a porous gold nanoshell. Gold was responsible for the photothermal effect, and irradiation with NIR light at 808 nm and the power of 2 W/cm\({}^{2}\) produced heat up to 71.1 \({}^{\circ}\)C. The authors proved the catalytic properties of the nanoagent in the experiment with H\({}_{2}\)O\({}_{2}\) decomposition, where 98.7% decomposition of this compound was noted after 3 h. The biological activity of nanoparticles was assessed in vitro using MCF-7 cells. The high biocompatibility (in dark conditions) and higher activity with combined therapies--photodynamic and photothermal--were reported in comparison to those with PDT and PTT applied separately. The high potential of the proposed approach was confirmed in the in vivo trial performed on MCF-7 tumor-bearing mice. An excellent result was noted for mice treated with combined therapy [58]. [PERSON] et al. reported the synthesis of TiO\({}_{2}\) and SiO\({}_{2}\)-based nanoparticles bearing Ce6 [60]. Firstly, the TiO\({}_{2}\) or SiO\({}_{2}\) nanoparticle core was covered with (3-aminopropyl)triethoxysilane, as well as a shell to which Ce6 was attached via an amide bond. Titanium oxide nanoparticles revealed higher biological activity with high ROS generation, especially OH: radicals, which was confirmed under light irradiation of the U87 glioblastoma cell line inside. Despite the high anticancer activity, significant activity in dark conditions was also noticed [60]. The mesoporous silicon nanoparticles (MSNs) loaded with Ce6, L-butionine sulfoximine (BSO), and further with cisplatin were recently proposed by [PERSON] et al. as a multifunctional antimutom agents, combining PDT with classic chemotherapy [61]. The in vitro and in vivo experiments based on A549/DDP tumor-bearing nude mice using nanoparticles revealed that all components were released separately under acidic conditions in tumor tissue, leading to a tumor inhibitory rate (vs. saline) of 73.8%. The data described in Section 2.4 are summarized in Table 4. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Type of NPs** & **Size of NPs** & **Preparation Method** & **Wavelength** & **Light Dose/Light Power** & **Cell Type** & **Cell Viability** & **Ref.** \\ \hline CuS & 6.5 nm & chemical reduction of copper(I) chloride in octadecene (ODE) & 670 and 808 & 670 and 808 & 100 mW/cm\({}^{2}\) for 670 nm and 2 W/cm\({}^{2}\) for 808 nm & MDA-MB-231 breast cancer cells & 16\% & [50] \\ \hline Pd nanospheres & 90 nm & hydrothermal synthesis & 660 and 808 & 660 nm and 2 W/cm\({}^{2}\) for 808 nm & HeLa cells & 14\% & [51] \\ \hline \hline \end{tabular}
\end{table} 
Table 4: A summary of the data presented in Section 2.4.