Indocyanine green modified silica shells for colon tumor marking

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Surgical Oncology

Background:

• Traditional India ink for surgical tumor marking has limitations, including poor subsurface imaging and potential complications like abscesses and intestinal perforation.
• Non-fluorescent dyes lack the ability to be imaged beneath the tissue surface, hindering precise surgical guidance.

Purpose of the Study:

• To develop and evaluate a novel infrared marker for enhanced surgical tumor localization.
• To overcome the limitations of India ink by utilizing near-infrared fluorescence imaging capabilities.

Main Methods:

• Development of an indocyanine green (ICG) and hollow silica nanoshell (ICG/HSS) complex using amine linkers for non-covalent adsorption.
• Synthesis of hollow silica nanoshells with varying wall thicknesses (100 nm and 2 μm) and characterization of ICG coating.
• In vitro, ex vivo, and in vivo testing to assess fluorescence emission, imaging depth, diffusion, and longevity.

Main Results:

• Thinner ICG coatings (< 3 nm) on 100 nm nanoshells exhibited higher fluorescence efficiency compared to thicker coatings (6 nm) on 2 μm shells, attributed to reduced self-quenching.
• Ex vivo imaging demonstrated visibility of the ICG/HSS marker up to 1.5 cm beneath tissue.
• In vivo studies confirmed no diffusion of the ICG/nanoparticle marker, with sustained imageability for up to 12 days.

Conclusions:

• The novel ICG/HSS nanoparticle system provides a safe and effective infrared marker for surgical tumor marking.
• This advanced marker enables deep tissue visualization and precise localization, surpassing conventional India ink methods.
• The ICG/HSS marker demonstrates excellent stability and longevity in vivo, offering significant advantages for oncologic surgery.