A highly sensitive and selective nanosensor for near-infrared potassium imaging

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Optical Imaging

Background:

• Potassium ion (K+) concentration dynamics are crucial in biological processes.
• Existing optical K+ probes lack sensitivity for physiological fluctuations in vivo.
• Current probes are limited by short-wavelength excitation, hindering deep tissue imaging.

Purpose of the Study:

• To develop a highly sensitive and selective nanosensor for near-infrared (NIR) potassium ion (K+) imaging.
• To enable optical monitoring of K+ fluctuations in living cells and deep tissues.
• To overcome the limitations of existing K+ probes in sensitivity and tissue penetration.

Main Methods:

• Fabrication of a nanosensor by encapsulating upconversion nanoparticles (UCNPs) and a K+ indicator within mesoporous silica nanoparticles.
• Coating the nanoparticles with a K+-selective filter membrane to adsorb K+ and exclude interfering cations.
• Utilizing UCNPs to convert NIR excitation light to ultraviolet light for K+ indicator excitation.

Main Results:

• The developed nanosensor demonstrates high sensitivity and selectivity for K+ detection.
• Successful imaging of K+ concentration fluctuations in cultured cells.
• Demonstrated applicability for monitoring K+ in intact mouse brains using NIR excitation.

Conclusions:

• The novel nanosensor provides a significant advancement for optical K+ imaging.
• It enables sensitive, selective, and deep-tissue monitoring of physiological K+ dynamics.
• This technology holds promise for studying biological processes involving K+ fluctuations in vivo.