An upconversion nanoparticle-based fluorescence resonance energy transfer system for effectively sensing caspase-3...

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Biochemistry

Background:

• Caspase-3 is a key enzyme in apoptosis.
• Sensitive detection of caspase-3 activity is crucial for studying cellular processes and disease.
• Existing detection methods may lack sensitivity or require complex procedures.

Purpose of the Study:

• To develop a novel fluorescence resonance energy transfer (FRET) sensing platform for sensitive detection of caspase-3 activity.
• To utilize upconversion nanoparticles (UCNPs) as energy donors and Rhodamine B (RB) as an energy acceptor.
• To demonstrate the platform's utility in vitro and in live cells.

Main Methods:

• Fabrication of NaGdF4:Yb3+,Er3+@NaGdF4 UCNPs as energy donors.
• Immobilization of a phosphorylated RB-modified peptide containing a caspase-3 cleavage site and cell-penetrating peptide (CPP) motif onto the UCNP surface.
• Detection of caspase-3 activity based on the recovery of upconversion luminescence (UCL) upon peptide cleavage and RB release.

Main Results:

• The UCNP-based FRET platform demonstrated sensitive detection of caspase-3 activity.
• A linear relationship was observed between UCL recovery and caspase-3 concentration from 0.01 to 1000 pg mL-1.
• A low limit of detection (LOD) of 0.01 pg mL-1 (S/N = 3) was achieved.
• The platform showed reasonable selectivity and was successfully applied to monitor caspase-3 activity in drug-induced apoptosis of HeLa cells.

Conclusions:

• The developed UCNP-based FRET sensing platform offers a sensitive and selective method for detecting caspase-3 activity.
• This platform has potential applications in biological research and clinical diagnostics.
• The study highlights the utility of UCNPs in developing advanced biosensing tools.