A photothermal effect-based chiral sensor for chiral discrimination and sensitive detection.

Area of Science:

• Analytical Chemistry
• Nanomaterials Science
• Biophysics

Background:

• Chiral analysis is crucial in analytical chemistry, requiring simple and portable devices.
• The photothermal (PT) effect offers a promising mechanism for developing novel sensing platforms.
• Gold nanorods (GNRs) exhibit excellent photothermal conversion properties due to their localized surface plasma resonance (LSPR).

Purpose of the Study:

• To develop a simple, portable chiral sensor for the recognition and detection of tryptophan (Trp) isomers.
• To leverage the photothermal effect for chiral discrimination.
• To achieve sensitive quantification of L-tryptophan (L-Trp).

Main Methods:

• Fabrication of GNRs@BSA hybrid nanomaterials via Au-S bonds, utilizing GNRs as PT reagents and bovine serum albumin (BSA) as a natural chiral source.
• Chiral recognition based on the differential interaction between GNRs@BSA and L-Trp versus D-Trp.
• Detection of chiral discrimination via changes in temperature under near-infrared (NIR) light irradiation, correlating with thermal conductivity differences.

Main Results:

• GNRs@BSA demonstrated higher affinity for L-Trp compared to D-Trp, attributed to BSA's inherent chirality.
• Significant temperature differences were observed between GNRs@BSA//L-Trp and GNRs@BSA//D-Trp systems under NIR irradiation, indicating successful chiral discrimination.
• The developed PT sensor achieved sensitive detection of L-Trp with a linear range of 1 μM–10 mM and a limit of detection (LOD) of 0.43 μM.

Conclusions:

• A simple and portable photothermal chiral sensor was successfully developed for discriminating tryptophan isomers.
• The GNRs@BSA system effectively utilizes inherent biomolecular chirality for selective recognition.
• The developed sensor shows potential for sensitive and specific detection of L-tryptophan in analytical applications.