Specific visualization of tumor cells using upconversion nanophosphors.

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Molecular Biology

Background:

• Targeted constructs using photoluminescent nanoparticles are crucial for medical diagnostics.
• Upconversion nanophosphors (UCNPs) offer stable optical properties within biological tissues.
• HER2 receptor overexpression is common in several human cancers, making it a key diagnostic target.

Purpose of the Study:

• To develop a targeted two-component construct for selective labeling of HER2-overexpressing tumor cells.
• To utilize upconversion nanophosphors (UCNPs) and an anti-tumor antibody fragment for enhanced tumor cell visualization.
• To demonstrate the construct's efficacy in targeting specific cancer cell lines.

Main Methods:

• Development of a two-component construct using UCNPs and 4D5 single-chain variable fragment (scFv).
• Employment of a barnase:barstar (Bn:Bs) protein pair as a molecular adapter for self-assembly.
• Testing the construct's binding selectivity against HER2-overexpressing SK-BR-3 cells.

Main Results:

• A stable, targeted construct (4D5 scFv-Bn : UCNP-Bs) was successfully synthesized.
• The construct demonstrated high affinity and selective binding to HER2-positive SK-BR-3 human breast adenocarcinoma cells.
• The self-assembly mechanism using the Bn:Bs pair proved effective for construct formation.

Conclusions:

• The developed construct enables precise visualization of tumor cells overexpressing HER2.
• This approach offers a versatile platform for creating similar constructs for detecting various disease markers.
• The study highlights the potential of UCNP-based targeted therapies in oncology.