Bismuth-Loaded Poly(α-amino acid) Nanoparticles for CT and Fluorescence Bimodal Imaging

Area of Science:

• Biomedical Imaging
• Nanotechnology
• Materials Science

Background:

• X-ray computed tomography (CT) has high spatial resolution but low sensitivity, limiting early disease diagnosis.
• Fluorescence imaging (FI) offers high sensitivity but suffers from poor spatial resolution and limited tissue penetration.
• Bimodal imaging combining CT and FI provides complementary advantages for enhanced diagnostic capabilities.

Purpose of the Study:

• To develop and evaluate novel bismuth-loaded poly(α-amino acid) nanoparticles (Bi NPs) for CT and fluorescence bimodal imaging.
• To assess the potential of Bi NPs as contrast agents for improved disease diagnosis.

Main Methods:

• Synthesis of bismuth-loaded poly(α-amino acid) nanoparticles (Bi NPs), including Bi@POS, Bi@POS-FITC, and Bi@POS-ICG.
• Integration of bismuth complexes with fluorescent dyes (fluorescein isothiocyanate - FITC, indocyanine green - ICG).
• Evaluation of X-ray attenuation and fluorescence emission properties.
• In vitro and in vivo studies to assess bimodal imaging performance, CT contrast enhancement, and fluorescence signal duration.

Main Results:

• Bi NPs demonstrated superior X-ray attenuation and fluorescence emission.
• The nanoparticles exhibited significantly enhanced CT contrast and prolonged fluorescence signals in both in vitro and in vivo experiments.
• Poly(α-amino acid)s with catechol moieties effectively chelated Bi3+ and showed reactive oxygen and nitrogen species (RONS) scavenging activity.

Conclusions:

• Bismuth-loaded poly(α-amino acid) nanoparticles (Bi NPs) show excellent bimodal imaging performance.
• These Bi NPs offer enhanced CT contrast and prolonged fluorescence, indicating significant potential as advanced contrast agents for diagnostic applications.
• The RONS scavenging activity of the poly(α-amino acid) backbone adds a potential therapeutic dimension.