Surfactant-Free Interface Suspended Gold Graphitic Surface-Enhanced Raman Spectroscopy Substrate for Simultaneous...

Area of Science:

• Analytical Chemistry
• Materials Science
• Biomedical Engineering

Background:

• Simultaneous detection of multiplex analytes with varying solubility is crucial for pharmaceutical analysis, particularly for synergistic therapies.
• Surface-enhanced Raman spectroscopy (SERS) offers sensitive, label-free detection but faces limitations in multiphase applications due to substrate modification requirements.
• Existing SERS methods often require surfactants or inducers, hindering broad application in complex biological systems.

Purpose of the Study:

• To develop an innovative SERS substrate for simultaneous multiphase analysis of multiplex analytes.
• To overcome the limitations of traditional SERS methods by eliminating the need for surfactants or surface modification.
• To demonstrate the utility of the developed substrate for ex vivo pharmacokinetic analysis of co-administered drugs.

Main Methods:

• Fabrication of a graphene-isolated-gold-nanocrystal SERS substrate capable of self-suspension at multiphase interfaces.
• Utilizing the unique vibration band of the graphitic shell as an internal standard for enhanced quantification accuracy.
• Performing ex vivo experiments with mimic lipid- and water-soluble drugs in mice to validate multiphase enrichment and detection capabilities.

Main Results:

• The developed gold graphitic SERS substrate spontaneously suspends at interfaces without surfactants, ensuring analyte proximity.
• The substrate enables simultaneous enrichment and sensitive SERS detection of analytes from different phases without interference.
• Accurate quantification was achieved using the graphitic shell's vibration band as an internal standard, validated in ex vivo drug analysis.

Conclusions:

• A novel, surfactant-free SERS substrate facilitates simultaneous multiphase analysis and enrichment.
• The substrate's design enhances SERS quantification accuracy through an intrinsic internal standard.
• This technology shows significant potential for simultaneous multiplex pharmacokinetic analysis of co-administered drugs.