In situ nanozyme assembly amplification enables sub-femtomolar-level colorimetric immunoassay

Area of Science:

• Biochemistry
• Nanotechnology
• Analytical Chemistry

Background:

• Colorimetric immunoassays are crucial for biomarker detection.
• Current methods face limitations in sensitivity, hindering early disease diagnosis.

Purpose of the Study:

• To develop an in situ nanozyme assembly amplification strategy for ultrasensitive colorimetric immunoassays.
• To enhance the detection limit of protein biomarkers.

Main Methods:

• Programmable bioaffinity-driven assembly of streptavidin-Pd@Pt and biotin-Pd@Pt nanozymes.
• Stepwise anchoring and recruitment of nanozymes onto immunocomplexes.
• Utilizing the peroxidase-like catalytic activity of Pd@Pt nanozymes for signal amplification.

Main Results:

• Achieved ultrasensitive detection of interleukin-10 (IL-10) at sub-femtomolar levels (10 fg mL⁻¹).
• Demonstrated a two-order magnitude improvement in sensitivity compared to HRP-based assays.
• Localized nanozyme assembly significantly increased local nanozyme concentration and catalytic accessibility.

Conclusions:

• The in situ nanozyme assembly strategy offers a powerful platform for ultrasensitive biomarker detection.
• This approach transcends sensitivity limitations of traditional colorimetric immunoassays.
• Provides a versatile and translatable method for clinical diagnostics.