Abstract
In this study, a rationally-designed 2,4,6-trinitrotoluene (TNT) binding peptide derived from an amino acid sequence of the complementarity-determining region (CDR) of an anti-TNT monoclonal antibody was used for TNT detection based on a maleimide-functionalized surface plasmon resonance (SPR) sensor. By antigen-docking simulation and screening, the TNT binding candidate peptides were obtained as TNTHCDR1 derived from the heavy chain of CDR1, TNTHCDR2 derived from CDR2, and TNTHCDR3 from CDR3 of an anti-TNT antibody. The binding events between candidate peptides and TNT were evaluated using the SPR sensor by direct determination based on the 3-aminopropyltriethoxysilane (APTES) surface. The TNT binding peptide was directly immobilized on the maleimide-functionalized sensor chip surface from N-γ-maleimidobutyryl-oxysuccinimide ester (GMBS). The results demonstrated that peptide TNTHCDR3 was identified and selected as a TNT binding peptide among the other two candidate peptides. Five kinds of TNT analogues were also investigated to testify the selectivity of TNT binding peptide TNTHCDR3. Furthermore, the results indicated that the APTES-GMBS-based SPR sensor chip procedure featured a great potential application for the direct detection of TNT.
Highlights
Due to the threat of global terrorism acts and the needs of homeland security, there has been a great increase in the development of sensitive, non-false alarm, portable, and cheap platforms to monitor ultra-trace levels of explosives
For the development of a novel detection system for TNT, it was a challenge that rationally-designed peptides were directly immobilized on the sensor chip surface for TNT detection, which required a high binding capacity to LMW compounds
Compared with our preliminary results of using the CM5 chip and self-assembled monolayer-based peptide-functionalized surface plasmon resonance (SPR) gold chip, the maleimide-based sensor surface chip is promising for screening TNT binding candidate peptides since APTES are short organic molecules approximately 0.6 nm in length—much shorter than the CM5 dextran matrix (100 nm)
Summary
Due to the threat of global terrorism acts and the needs of homeland security, there has been a great increase in the development of sensitive, non-false alarm, portable, and cheap platforms to monitor ultra-trace levels of explosives. Biomolecule recognition elements—peptides—are gaining tremendous attention for specific explosive detection because of their high affinity, long-term stability and sensitivity, and their capability of self-assembly on various materials (including nanoparticles and nanotubes) compared with other biological components, such as cells, proteins, and antibodies. They can be chemically engineered to obtain and design target peptides for specific demands [3,5,10,11]. All these advantages offer an ideal sensing element for explosive detection
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