Dual-fluorophore Raspberry-like Nanohybrids for Ratiometric pH Sensing

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Dye leaching from silica nanoparticles is a significant challenge in developing reliable fluorescent sensors.
• Ratiometric fluorescence sensing offers enhanced accuracy by using a reference signal to compensate for environmental fluctuations.

Purpose of the Study:

• To develop raspberry-like silica nanohybrids for ratiometric fluorescence-based pH sensing.
• To address the issue of dye leaching in silica nanoparticle-based sensors.
• To create a stable and sensitive platform for pH detection.

Main Methods:

• Synthesized silica nanoparticles doped with pH-sensitive 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) and reference dye rhodamine B isothiocyanate (RBTIC).
• Utilized a polyelectrolyte-assisted method for incorporating anionic HPTS into silica nanoparticles to prevent leaching.
• Characterized the nanohybrids' morphology and optical properties.
• Evaluated pH sensing performance using fluorescence intensity ratios at specific excitation and emission wavelengths.

Main Results:

• Successfully fabricated raspberry-like silica nanohybrids with HPTS and RBTIC-doped nanoparticles.
• Demonstrated effective prevention of HPTS dye leaching through polyelectrolyte-assisted incorporation.
• Observed a dynamic, pH-dependent fluorescence response in the acidic range.
• Established the ratiometric fluorescence signal based on the intensity ratio at 510 nm and 583 nm.

Conclusions:

• The developed nanohybrids are effective for ratiometric pH sensing, particularly in acidic environments.
• The polyelectrolyte-assisted approach provides a robust solution to dye leaching in silica nanoparticles.
• This platform holds potential for creating multifunctional and multiplexed sensing applications by incorporating various dyes or receptors.