Improving 5-halouracils SERS detection driven by Watson & Crick pairing recognition. A spectroscopic & DFT study
Antonio M Neto1, Maycom C Valeriano1, Marcia L A Temperini2
1Laboratório de Espectroscopia Molecular e Atômica, Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, São Paulo, Brazil.
Summary
This study enhances the detection of halogenated uracils using Surface-Enhanced Raman Scattering (SERS) by employing adenine to improve signal strength. This method achieves a low limit of detection for 5-fluorouracil, crucial for environmental and biological sample analysis.
Area of Science:
- Analytical Chemistry
- Spectroscopy
- Computational Chemistry
Background:
- Halogenated uracil derivatives (5-fluoro-, 5-chloro-, 5-bromouracil) are significant in pharmacology, as biomarkers, and as environmental pollutants.
- Detecting these compounds at low levels in biological and environmental samples requires sensitive analytical methodologies.
- Surface-Enhanced Raman Scattering (SERS) is a promising technique for sensitive detection, but understanding analyte-metal interactions is key to maximizing its potential.
Purpose of the Study:
- To investigate the interaction of 5-halouracils with silver nanoparticles (AgNPs) using experimental and theoretical approaches.
- To explore the use of adenine as a strategy to enhance SERS detection of 5-halouracils.
- To determine the limit of detection (LOD) for 5-fluorouracil (5-FU) using the developed SERS method.
Main Methods:
- Experimental SERS measurements of 5-halouracils on AgNPs.
- Density Functional Theory (DFT) calculations to understand analyte-metal surface interactions.
- Formation of base pairs between 5-halouracils and adenine to enhance SERS signals.
Main Results:
- Spectroscopic behavior of 5-halouracils correlated with halogen electronegativity, influencing CC and CO stretching modes.
- Adenine facilitated improved orientation of 5-halouracils on AgNPs, leading to enhanced SERS signals.
- A limit of detection (LOD) of 2.36 nmol L⁻¹ was achieved for 5-FU.
- DFT calculations and SERS spectra indicated hydrogen bonding (NH----N) between adenine and AgNPs is crucial for signal enhancement.
Conclusions:
- The interaction of 5-halouracils with AgNPs can be modulated by electronegativity and base pairing strategies.
- Adenine significantly enhances SERS detection of 5-halouracils by promoting favorable orientations and hydrogen bonding.
- This approach offers a highly sensitive method for quantifying trace levels of 5-halouracils in analytical applications.
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