# BODIPY-Based Nanomaterials--Sensing and Biomedical Applications
## 2 Metallic Nanoparticles@BODIPY
### Cancer Diagnosis and Therapy
#### 2.2.4 Other Metallic Nanoparticles  
Metal nanoparticles bearing a BODIPY photosensitizer were employed to overcome PDT limitations related to low light penetration of tissues. The delivery of the light is essential to excite the PS and produce singlet oxygen--the anticancer agent. Thus, [PERSON] and co-workers applied the persistent fluorescence phenomenon via a FRET-matching BODIPY dye [80]. They built zinc-germanogalate-based (Zn\({}_{2.78}\)Ga\({}_{1.68}\)Ge\({}_{1.00}\)O\({}_{8}\):Cr\({}_{0.01}\),Pr\({}_{0.02}\)) BODIPY-functionalized nanoparticles (Figure 23). The obtained nanoagent was excited with light at 254 nm before being introduced to the tumor. Persistent luminescence is caused by a cascade of electron recombination in the nanoparticle. Firstly, after photons absorption, excited electrons are captured by native defects of zinc-germanogalate. When the excitation process is finished, the electrons leave holes. Due to the spectral overlap of Cr\({}^{3+}\) ions, the released energy is transferred to these ions in a non-radiative manner. Electrons located at 3d orbitals of chromium ions are excited to triplet states and move to deeper traps that, after persistent energy transfer, stop releasing energy and are able to emit light persistently. Emitted light (at ca. 500 nm) is suitable to be absorbed by the attached BODIPY dye, which then generates singlet oxygen up to 80 min after excitation. In vivo experiments concluded a 15% reduction of the tumor volume. This modest pilotage result might open up a new pathway for PDT development [80; 81]. Figure 22: The representative chemical structure of Materials Institute Lavoisier (MILs). MIL-101 (Fe) was obtained with the use of 2-aminoterephthalalc acid and modified with BODIPY dyes coated with silicon(IV) dioxide [79]. The orange lines represent the 2-aminoterephthalalc acid moieties, and the six nodes where they meet are occupied by Fe\({}_{3}\)(\(\upmu_{3}\)-O)Cl(H\({}_{2}\)O)\({}_{2}\) clusters. Silver-based BODIPY-bearing nanoparticles were developed for selective bacteria recognizing and combating (Figure 24). [PERSON] and co-workers linked iodinated BODIPY via galactose-polymer with silver nanoparticles [82]. Iodine atoms enriched singlet oxygen production via a phenomenon known as the \"heavy atom effect\". Galactose-polymer was responsible for selective binding with bacteria cells. The platform was formed with silver nanoparticles revealing some antibacterial effects. The authors confirmed, with a laser scanning confocal microscope, efficient gathering of nanoparticles in the bacteria in comparison to mammalian cells. The bactericidal activity of obtained nanoparticles activated with light was assigned to MIC = 50 pmol/mL, whereas the MIC value of these particles in dark conditions was 2500 pmol/mL. The authors treated the NIH/3T3 cell line with obtained nanoparticles (400 pmol/mL) and noticed that over 80% of the cells survived. BODIPY-Ag nanoparticles (10 nmol/mL) incubated with erythrocytes caused negligible hemolysis. Therefore, it was concluded that the nanoparticles revealed high biocompatibility [82]. In search of new tools for PTT and PDT implementation, [PERSON] and co-workers developed an aza-BODIPY probe containing mesoporous black  
Figure 23: The chemical structure of zinc-germanogallate-based BODIPY-functionalized nanoparticles [80]. Figure 24: The chemical structure of silver nanoparticles functionalized with iodinated BODIPY linked to galactose-polymer [82]. nanoparticles named MTAB (Figure 25) [83]. The synthesis of MTAB occurred under analytical surveillance using such methods as XRD, \({}^{1}\)H NMR, and Fourier-transform infrared (FTIR) spectroscopy. First, the authors obtained mesoporous anatase TiO\({}_{2}\) nanoparticles that consequently underwent aluminum reduction to produce mesoporous black anatase nanoparticles (MT).