Nanoporous Gold Disks Functionalized with Stabilized G-Quadruplex Moieties for Sensing Small Molecules

Area of Science:

• Analytical Chemistry
• Nanotechnology
• Biochemistry

Background:

• Guanine-quadruplex (G4) structures offer unique molecular recognition capabilities.
• Nanoporous gold (NPG) disks provide abundant plasmonic hotspots for signal enhancement.
• Label-free detection of small molecules remains a challenge in various fields.

Purpose of the Study:

• To develop a sensitive and selective method for detecting small molecules using G4-functionalized NPG disks and SERS.
• To investigate the potential of G4 structures for capturing target molecules via non-canonical interactions.
• To establish a new technique for studying G4 formation and evolution.

Main Methods:

• Functionalization of NPG disks with stabilized G4 moieties (d(GGT)7GG sequence).
• Utilizing π-π stacking and electrostatic attractions for selective capture of target molecules.
• Employing surface-enhanced Raman spectroscopy (SERS) for sensitive signal detection.

Main Results:

• Achieved label-free detection of malachite green (MG) with a limit of detection as low as 50 pM.
• Demonstrated high specificity against potential interferents.
• Developed a portable probe system achieving a 5.0 nM limit of detection, meeting EU regulatory standards.

Conclusions:

• The G4-functionalized NPG-SERS platform provides a highly sensitive and selective method for small molecule detection.
• This approach offers a novel strategy for studying G4 structures and their interactions.
• The developed technology holds translational potential for real-world applications, such as environmental monitoring.