Abstract
In this study, we developed a surface plasmon resonance (SPR) sensor chip based on 2,4,6-trinitrotoluene (TNT) recognition peptide-modified single-walled carbon nanotubes (SWCNTs). The carboxylic acid-functionalized SWCNTs were immobilized on a 3-aminopropyltriethoxysilane (APTES)-modified SPR Au chip surface. Through π-stacking between the aromatic amino acids and SWCNTs, the TNT recognition peptide TNTHCDR3 was immobilized onto the surface of the SWCNTs. The peptide–SWCNTs-modified sensor surface was confirmed and evaluated by atomic force microscope (AFM) observation. The peptide–SWCNTs hybrid SPR sensor chip exhibited enhanced sensitivity with a limit of detection (LOD) of 772 ppb and highly selective detection compared with commercialized carboxymethylated dextran matrix sensor chips.
Highlights
Surface plasmon resonance (SPR) is a powerful technique for the study of large biomolecule interactions in real time with a simple and rapid analysis procedure
The results reveal that the proposed method offers enhanced sensitivity, selectivity, and long-term stability in the detection of TNT explosives
The surface structure and morphology of the peptide–single-walled carbon nanotubes (SWCNTs) hybrid were analyzed by atomic force microscope (AFM)
Summary
Surface plasmon resonance (SPR) is a powerful technique for the study of large biomolecule interactions in real time with a simple and rapid analysis procedure. The principle of SPR is based on the fact that the signal is proportional to the refractive index (RI) of the medium near gold metal films. Great effects have been achieved in enhancing SPR signals using gold nanoparticles/rods, quantum dots, graphene oxide, or carbon nanotubes [1,4,5,6,7,8,9]. Self-assembled monolayers and dextran polymers are often used for immobilizing the ligand molecules on the gold surface. These extensive effects on the enhancement of the SPR signal were still mainly used for the direct detection of large molecules, such as proteins, DNA, and antibodies, and for the indirect
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