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Published on: February 28, 2018
Selective enrichment of microbiota-derived tryptophan metabolites in mouse faeces based on molecularly imprinted
Mengmeng Song1, Xianjie Sheng1, Genyi Ye2
1Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
Abstract:
Gut microbiota-derived tryptophan (TRP) metabolites, especially the indole derivatives, function as critical modulators of intestinal immune function and integrity via modulating the aryl hydrocarbon receptor pathway. Selective enrichment of these indole metabolites in biological samples is important for quantitative determination by routine methods such as HPLC. Here, we report a molecularly imprinted polymer (MIP) for solid-phase extraction (SPE) of TRP-derived indole metabolites from faeces of mice. The MIP was synthesized by surface polymerization by using indole-3-acetic acid (IAA) and acrylamide after cross-linking by ethylene glycol dimethacrylate (EGDMA) and initialed by 2',2-azobisisobutyronitrile (AIBN). The MIPs were then characterized by transmission electron microscope (TEM) and fourier transform infrared spectroscopy (FTIR), and the adsorption capacity, selectivity and reusability of MIPs were systematically evaluated. Results showed that IAA-MIPs showed a uniformly distributed nanoshell layer with a thin shell thickness of 26 nm. The IAA-MIPs could selectively adsorb IAA, indole-3-propionic acid (IPA), and indole-3-lactic acid (ILA) in a mixed solution that also contains TRP and tyrosine. The adsorption capacity of IAA-MIPs only slightly decreased with the increase of recycling use. As purification material for SPE, the IAA-imprinted polymers (IAA-MIPs) were successfully applied to extract IAA, IPA, and ILA from normal and colitis mice for HPLC determination. Collectively, these surface molecularly imprinted polymers could find extensive use to selective enrichment of microbiota-derived indole metabolites in biological samples.
Insights
Researchers developed a novel molecularly imprinted polymer (MIP) for selective solid-phase extraction (SPE) of gut microbiota-derived indole metabolites. This method enhances the accurate quantification of these crucial compounds in biological samples.
Area of Science:
- Analytical Chemistry
- Biochemistry
- Materials Science
Background:
- Gut microbiota-derived tryptophan (TRP) metabolites, particularly indole derivatives, are key regulators of intestinal immunity and integrity via the aryl hydrocarbon receptor pathway.
- Accurate quantification of these indole metabolites in biological samples is crucial for understanding their biological roles, necessitating efficient enrichment techniques.
Purpose of the Study:
- To develop and characterize a molecularly imprinted polymer (MIP) for the selective solid-phase extraction (SPE) of TRP-derived indole metabolites.
- To evaluate the adsorption capacity, selectivity, and reusability of the synthesized MIP for potential application in biological sample analysis.
Main Methods:
- Synthesis of a surface MIP using indole-3-acetic acid (IAA) as a template, acrylamide as a functional monomer, and ethylene glycol dimethacrylate (EGDMA) as a cross-linker.
- Characterization of the MIP using transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR).
- Evaluation of MIP performance in selective adsorption of indole metabolites (IAA, indole-3-propionic acid (IPA), indole-3-lactic acid (ILA)) from complex mixtures and application in SPE for HPLC determination.
Main Results:
- The synthesized IAA-MIPs exhibited a uniform nanoshell layer structure with a thickness of 26 nm.
- IAA-MIPs demonstrated high selectivity, effectively adsorbing IAA, IPA, and ILA while excluding TRP and tyrosine.
- The MIPs maintained good adsorption capacity after multiple recycling cycles and were successfully applied for the SPE of indole metabolites from normal and colitis mouse feces for HPLC analysis.
Conclusions:
- Surface molecularly imprinted polymers provide an effective and selective method for enriching microbiota-derived indole metabolites in biological samples.
- This MIP-based SPE approach facilitates the accurate quantitative determination of these important metabolites using techniques like HPLC, aiding further research into gut health and disease.
