Sensitive and selective localized surface plasmon resonance light-scattering sensor for Ag+ with unmodified gold...

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Biomolecular Sensing

Background:

• Localized surface plasmon resonance (LSPR) is a powerful optical phenomenon utilized in nanosensors.
• Gold nanoparticles (AuNPs) offer unique optical properties suitable for sensing applications.
• Silver ions (Ag+) play crucial roles in biological systems and environmental monitoring, necessitating sensitive detection methods.

Purpose of the Study:

• To develop a novel localized surface plasmon resonance (LSPR) light-scattering sensor for the detection of silver ions (Ag+).
• To utilize the specific recognition between Ag+ and cytosine-cytosine mismatched base pairs for sensing.
• To establish a sensitive and accurate method for quantifying Ag+ in various real-world samples.

Main Methods:

• Fabrication of a sensor using unmodified gold nanoparticles (AuNPs).
• Exploitation of the interaction between Ag+ and a specific oligonucleotide sequence (5'-TAC ATA CAT ACT ATC TAT CTA-3') leading to DNA desorption.
• Monitoring changes in LSPR light-scattering intensity upon Ag+ addition and subsequent AuNP aggregation.

Main Results:

• The addition of Ag+ caused oligonucleotide desorption from AuNPs, leading to AuNP aggregation.
• A significant enhancement in LSPR light-scattering intensity was observed, directly proportional to Ag+ concentration.
• The sensor demonstrated a linear detection range of 0.13–1.12 μM for Ag+ with a low limit of detection (LOD) of 62.0 nM.
• The method's efficacy was validated using a colorimetric approach and successfully applied to water and industrial product samples.

Conclusions:

• The developed LSPR light-scattering sensor provides a sensitive and specific method for Ag+ detection.
• The sensor's mechanism relies on Ag+-induced oligonucleotide desorption and subsequent AuNP aggregation.
• This novel sensing platform shows promise for practical applications in environmental monitoring and industrial quality control.