Dual-emissive silicon quantum dots as a ratiometric fluorogenic probe for alkaline phosphatase activity

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Traditional fluorescent silicon quantum dots (SiQDs) exhibit single-wavelength emission, limiting their application in ratiometric sensing.
• Ratiometric sensing offers advantages over single-wavelength methods by providing internal referencing, enhancing accuracy and reducing environmental interference.

Purpose of the Study:

• To develop dual-emissive silicon quantum dots (SiQDs) for ratiometric sensing applications.
• To create a sensitive and selective fluorescence assay for alkaline phosphatase (ALP) activity using the synthesized SiQDs.

Main Methods:

• Hydrothermal synthesis of dual-emissive SiQDs with distinct emission peaks at ~400 nm and ~510 nm.
• Elucidation of the photoluminescence mechanism of the dual-emissive SiQDs.
• Development of a ratiometric fluorescence assay for ALP activity utilizing the inner-filter effect between SiQDs, PNPP, and PNP.

Main Results:

• The synthesized SiQDs exhibited dual emission peaks, enabling ratiometric detection.
• The ratiometric fluorescence assay demonstrated a linear response for ALP activity from 1-60 U/L with a low detection limit of 0.79 U/L.
• The assay showed excellent selectivity and was successfully validated for ALP quantification in animal serum.

Conclusions:

• Dual-emissive SiQDs provide a versatile platform for ratiometric biosensing.
• The developed assay offers a simple, robust, and sensitive method for ALP activity detection.
• This work expands the toolkit of fluorescent nanomaterials for advanced biosensing applications.