Octahedral silver oxide nanoparticles enabling remarkable SERS activity for detecting circulating tumor cells.

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Circulating tumor cell (CTC) detection is vital for cancer management but challenged by low sensitivity due to CTC rarity.
• Existing methods struggle to detect the extremely low concentrations of CTCs in peripheral blood.

Purpose of the Study:

• To design and synthesize novel octahedral silver oxide (Ag2O) nanoparticles for enhanced surface-enhanced Raman scattering (SERS) detection of CTCs.
• To develop a highly sensitive and selective SERS bioprobe for accurate CTC identification.

Main Methods:

• Synthesis of octahedral Ag2O nanoparticles with oxygen vacancy defects.
• Characterization of SERS properties and enhancement factors using 4-mercaptopyridine.
• Development of an Ag2O-based SERS bioprobe by modifying nanoparticles with biological molecules.
• Testing bioprobe specificity and sensitivity using cancer cells in rabbit blood and patient samples.

Main Results:

• Synthesized Ag2O nanoparticles exhibited an ultra-high SERS enhancement factor of 1.98×10^6.
• The SERS activity is attributed to synergistic effects of defect-promoted photo-induced charge transfer (PICT) and vibration coupling resonance.
• The Ag2O-based SERS bioprobe demonstrated excellent specificity and a detection limit of 1 CTC per mL.
• This marks the first successful use of a semiconductor SERS substrate for CTC detection.

Conclusions:

• Octahedral Ag2O nanoparticles serve as an effective semiconductor SERS platform for highly sensitive CTC detection.
• The developed SERS bioprobe meets the stringent requirements for detecting rare CTCs in cancer patients.
• This research offers new avenues for cancer diagnosis and the development of advanced SERS-based platforms.