Upconversion nanoparticles for sensitive and in-depth detection of Cu2+ ions

Area of Science:

• Analytical Chemistry
• Materials Science
• Biomedical Engineering

Background:

• Copper ions (Cu2+) are crucial in biological and environmental systems, necessitating sensitive detection methods.
• Existing fluorescence-based Cu2+ sensors face limitations in biological samples due to shallow light penetration.
• Near-infrared (NIR) light offers greater penetration depth but requires materials that convert NIR to visible light.

Purpose of the Study:

• To develop a facile method for in-depth detection of Cu2+ ions using fluorescence upconversion.
• To create a sensor capable of sensitive Cu2+ detection in complex biological and environmental samples.
• To leverage the advantages of NIR light for enhanced sensor performance.

Main Methods:

• Coating upconversion nanoparticles (UCNPs) with a mesoporous silica shell.
• Incorporating rhodamine B hydrazide, a Cu2+-sensitive fluorescent probe, into the silica shell.
• Utilizing UCNPs to convert NIR excitation light into visible light, which then excites the fluorescent probe.

Main Results:

• The developed UCNP-based sensor enables sensitive detection of Cu2+ ions.
• The system effectively converts NIR light to visible light, allowing for deep tissue penetration.
• Low autofluorescence and high NIR penetration depth facilitate detection in complex samples.

Conclusions:

• Fluorescence upconversion offers a feasible approach for sensitive and in-depth Cu2+ detection.
• This method overcomes the limitations of UV/visible light-based sensors in biological and environmental analyses.
• The UCNP-based sensor holds promise for various applications requiring deep-tissue or environmental sensing of copper ions.