Antigen-responsive molecular sensor enables real-time tumor-specific imaging.

Area of Science:

• Biomedical imaging
• Molecular diagnostics
• Cancer research

Background:

• Antibody-fluorophore conjugates offer potential for cancer cell detection but suffer from high background fluorescence.
• Current methods require removal of unbound antibodies, hindering real-time imaging and clinical application.
• Nonspecific uptake and long circulation times limit the clinical utility of existing conjugates.

Purpose of the Study:

• To develop a novel molecular sensor for fast and real-time fluorescence imaging of target cancer cells.
• To overcome limitations of high background noise and persistent retention associated with conventional antibody-fluorophore conjugates.
• To enable efficient in vitro and in vivo imaging of HER2-expressing cancer cells.

Main Methods:

• Development of an antigen-responsive molecular "on-off" sensor using trastuzumab-ATTO680 conjugate.
• Utilizing the fluorescence "on-off" property triggered by binding to the target antigen HER2.
• Application of the sensor for near-infrared fluorescence imaging of cancer cells.

Main Results:

• The trastuzumab-ATTO680 conjugate exhibits quenched fluorescence in the extracellular environment (off state).
• Upon binding to the HER2 antigen on cancer cells, the conjugate's fluorescence is significantly enhanced (on state).
• This molecular switch facilitates rapid and real-time imaging of target cancer cells in vitro and in vivo.

Conclusions:

• The antigen-responsive molecular "on-off" sensor enables unprecedented speed and clarity in cancer cell imaging.
• This innovative approach significantly reduces background noise, improving the accuracy of fluorescence detection.
• The developed sensor holds promise for enhanced real-time diagnostics and monitoring of HER2-positive cancers.