A visual chiroptical system with chiral assembly graphene quantum dots for D-phenylalanine detection

Area of Science:

• Analytical Chemistry
• Biochemistry
• Materials Science

Background:

• Chirality is crucial in life sciences, necessitating precise enantioselective recognition of amino acid isomers.
• Developing sensitive and visual detection methods for specific amino acid enantiomers, like D-phenylalanine (D-Phe), remains a challenge.

Purpose of the Study:

• To develop a novel chiroptical system for the visual and enantioselective detection of D-phenylalanine (D-Phe).
• To utilize graphene quantum dots (GQDs) and a chiral recognition element for sensitive fluorescence-based sensing.

Main Methods:

• Graphene quantum dots (GQDs) were functionalized with 1,3,5-triformylphloroglucinol-functionalized chiral (+)-diacetyl-L-tartaric anhydride (TPTA) to create a chiral assembly.
• The fluorescence intensity and luminance variations of the TPTA-assembled GQDs were correlated with D-Phe concentrations.
• A smartphone-assisted chiroptical system was employed for visual detection, and the method was validated in food matrices and for intracellular imaging.

Main Results:

• A linear relationship was observed between TPTA-assembled GQDs' fluorescence intensity and D-Phe concentration (0.1–5 μM), with a detection limit of 0.023 μM.
• Visual detection of D-Phe using a smartphone system achieved a detection limit of 0.050 μM.
• High spiked recoveries (86.20–110.0%) were obtained from food samples, and successful intracellular chiroptical imaging in response to D-Phe was demonstrated.

Conclusions:

• The developed TPTA-assembled GQDs offer a promising chiral nanomaterial for sensitive and visual detection of amino acid isomers.
• The smartphone-assisted chiroptical system provides a portable and effective tool for D-Phe detection in various applications, including bioimaging.
• This technique advances smart device applications for enantioselective analysis in life sciences and food safety.