Luminescent nanomaterials for droplet tracking in a microfluidic trapping array.

Area of Science:

• Nanotechnology
• Biomedical Diagnostics
• Materials Science

Background:

• High-throughput screening platforms are crucial for on-site disease detection, enabling simultaneous analysis of single-cell responses.
• Current multiplexed studies face limitations due to spectral overlap between tracking materials like organic dyes and common fluorophores.
• This spectral overlap restricts the application of existing methods in complex diagnostic assays.

Purpose of the Study:

• To address the spectral overlap issue in multiplexed diagnostics by utilizing rare earth (RE)-doped nanoparticles.
• To demonstrate the feasibility of RE-doped β-hexagonal NaYF4 nanoparticles as spectrally independent droplet trackers.
• To validate the use of these nanoparticles in conjunction with fluorescent microscopy and microfluidic platforms.

Main Methods:

• Employed rare earth (RE)-doped β-hexagonal sodium yttrium fluoride (NaYF4) nanoparticles (NPs) as tracking materials.
• Utilized europium (Eu3+)-doped (red emission) and terbium (Tb3+)-doped (green emission) NaYF4 NPs.
• Tested NPs on a fluorescent microscopy-based droplet microfluidic trapping array, co-encapsulating with fluorescent proteins (GFP/RFP) and cell viability stains.

Main Results:

• Demonstrated spectrally independent luminescence tracking using Eu3+ and Tb3+-doped NaYF4 NPs.
• Confirmed no spectral overlap between the nanoparticles themselves and common fluorophores or cell stains.
• Successfully characterized the luminescence properties of NPs with genetically modified cancer cell lines and live/dead cell stains.

Conclusions:

• Rare earth (RE)-doped NaYF4 nanoparticles provide a solution to spectral overlap in multiplexed diagnostics.
• These spectrally independent nanoparticles are suitable for tracking applications in microfluidic systems.
• The developed technique holds significant potential for advanced multiplexed disease detection and diagnostics platforms.