Natural Protein Photon Upconversion Supramolecular Assemblies for Background-Free Biosensing.

Area of Science:

• Biomaterials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Disease biomarker diagnosis is vital for cancer management but challenged by complex biological sample properties.
• Existing photon upconversion materials face limitations in biocompatibility, stability, and performance for biosensing applications.

Purpose of the Study:

• To develop novel photon upconversion supramolecular assemblies (PUSA) with enhanced properties for biosensing.
• To create a PUSA-based nanoprobe for the sensitive and specific detection of urinary sarcosine, a biomarker for prostatic carcinoma (PCa).

Main Methods:

• Self-assembly of natural proteins and triplet-triplet annihilation upconversion (TTA-UC) pairs to form PUSA nanoparticles.
• Characterization of PUSA properties including size, oxygen tolerance, biocompatibility, and storage stability.
• Integration of PUSA with sarcosine oxidase for developing a near-infrared (NIR)-excitable nanoprobe for urinary sarcosine detection.

Main Results:

• Fabricated PUSA nanoparticles (∼44.1 nm) with excellent oxygen tolerance, biocompatibility, and lyophilization stability.
• Demonstrated that steric hindrance in PUSA enhances water dispersibility and upconversion performance.
• Developed a NIR-excitable PUSA nanoprobe capable of background-free detection and quantification of urinary sarcosine, enabling visual identification of PCa samples.

Conclusions:

• The developed PUSA represents a significant advancement in photon upconversion materials, offering superior properties for biosensing.
• The PUSA-based nanoprobe facilitates non-invasive, sensitive, and visual detection of PCa biomarkers, with potential for improved clinical diagnostics.
• This work opens new avenues for upconversion biosensing in disease diagnosis and monitoring.