Nanoparticle-Assisted Nuclear Relaxation-Based Detection of Oligonucleotides

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Nuclear relaxation techniques are sensitive to the microenvironment of paramagnetic centers.
• Paramagnetic centers can alter the transverse relaxation time (T2) of water protons, enabling target detection.
• Existing methods may lack simplicity or speed for certain applications.

Purpose of the Study:

• To develop a novel "on-off" oligonucleotide detection scheme.
• To utilize gadolinium phthalocyanine (GdTcPc)-grafted silica nanoparticles as paramagnetic centers for detection.
• To establish a simple, fast, and selective method for oligonucleotide quantification.

Main Methods:

• Conjugating a probe oligonucleotide to GdTcPc-grafted silica nanoparticles.
• Measuring changes in the transverse relaxation time (T2) using a benchtop relaxometer.
• Quantifying target oligonucleotide concentration based on the observed increase in ΔT2.

Main Results:

• An "on-off" detection scheme for oligonucleotides in aqueous solutions was successfully developed.
• The increase in ΔT2 was found to be proportional to the target oligonucleotide concentration.
• A linear detection range of 30–140 nM was achieved, with a detection limit of 15 nM.

Conclusions:

• The developed nuclear relaxation-based method provides a simple, fast, and selective means for oligonucleotide detection.
• This technique shows promise for applications in point-of-care diagnostics.
• The use of GdTcPc-grafted silica nanoparticles offers a novel platform for biosensing.