352
N. Ashwin Kumar et al.
Fig. 10 Schematic representation of Bismuth based nanomaterials for in-vivo imaging applications. Bismuth possesses similar characteristics of GNPs, enabling them for X-ray imaging,
radiosensitizer, and optical imaging applications
in vivo imaging applications. BSA-Bi nanomaterials were synthesized using acidic
conditions facilitates the coordination of Bi ions and BSA. Further changing the pH
from acidic to basic condition (pH = 12), the nucleation state of the BSA-Bi ions
converts to BSA capped Bismuth nanoparticles with a size less than 10 nm. These
nanoparticles possess a direct bandgap of 1.3 eV, which exhibits absorbance at NIR
that aids in photo-thermal effects for therapeutic applications. BSA-Bi NPs were
injected intravenously into the tumor region via EPR effect, as shown in Fig. 11 [95].
Compared to metallic Bismuth, bismuth chalcogenide possesses enhanced CT
and therapeutic effects [96]. In 2009, Lanza’s group developed soft bismuth encapsulated polymeric nanoparticles with high metallic content and provided enhanced
CT signal in vivo. Another work reports Bi 2 S 3 synthesized hard bismuth nanoparticles [98, 99]. Monodispersed Bi nanoparticles are produced using oleyl amine as a
reducing agent but showed weak interaction during the washing step. However, the
bismuth-based CT contrast was not well studied and is still in the primitive stage due
to the challenges in loading bismuth, controlling the size and surface modification of
the particles. Polyvinyl pyrrolidone coated cubic shaped bismuth sulphide nanocrystals were developed for pre-clinical lymph node imaging. These nanocrystals showed
a five-fold increase in CT contrast compared to regular iodine-based contrast agents
with longer circulation time and having a similar toxicity trend of Iodine. Compared
to bismuth sulphosalicylate ionic form (LD50 at 8 mM) is more toxic than bismuth
nanocrystals (LD50 at 100 mM) [98]. Ultrasmall sized Bismuth Sulphide nanoparticles (1–2 nm) are efficient compared to larger particles due to short circulation time,
N. Ashwin Kumar et al.
Fig. 10 Schematic representation of Bismuth based nanomaterials for in-vivo imaging applications. Bismuth possesses similar characteristics of GNPs, enabling them for X-ray imaging,
radiosensitizer, and optical imaging applications
in vivo imaging applications. BSA-Bi nanomaterials were synthesized using acidic
conditions facilitates the coordination of Bi ions and BSA. Further changing the pH
from acidic to basic condition (pH = 12), the nucleation state of the BSA-Bi ions
converts to BSA capped Bismuth nanoparticles with a size less than 10 nm. These
nanoparticles possess a direct bandgap of 1.3 eV, which exhibits absorbance at NIR
that aids in photo-thermal effects for therapeutic applications. BSA-Bi NPs were
injected intravenously into the tumor region via EPR effect, as shown in Fig. 11 [95].
Compared to metallic Bismuth, bismuth chalcogenide possesses enhanced CT
and therapeutic effects [96]. In 2009, Lanza’s group developed soft bismuth encapsulated polymeric nanoparticles with high metallic content and provided enhanced
CT signal in vivo. Another work reports Bi 2 S 3 synthesized hard bismuth nanoparticles [98, 99]. Monodispersed Bi nanoparticles are produced using oleyl amine as a
reducing agent but showed weak interaction during the washing step. However, the
bismuth-based CT contrast was not well studied and is still in the primitive stage due
to the challenges in loading bismuth, controlling the size and surface modification of
the particles. Polyvinyl pyrrolidone coated cubic shaped bismuth sulphide nanocrystals were developed for pre-clinical lymph node imaging. These nanocrystals showed
a five-fold increase in CT contrast compared to regular iodine-based contrast agents
with longer circulation time and having a similar toxicity trend of Iodine. Compared
to bismuth sulphosalicylate ionic form (LD50 at 8 mM) is more toxic than bismuth
nanocrystals (LD50 at 100 mM) [98]. Ultrasmall sized Bismuth Sulphide nanoparticles (1–2 nm) are efficient compared to larger particles due to short circulation time,