Design of Ultra‐Sensitive Diagnosis for Anthrax Protective Antigen base on Polyvalent Directed Peptide Polymer (PDPP) Using Horizontally Stacked Hexagonal ZnO Platelets

Abstract

Protective antigen (PA) is a component of anthrax toxin produced by Bacillus anthracis. Although Several approaches have proposed to treat PA as it is an attractive target for toxin neutralization, high lethality and potential as a bioweapon place ultra‐sensitive diagnostic system on demand. Most of the current detection methods rely on specificity of antibody toward its cognate antigen. Herein, we proposed peptide as a novel diagnostic probe with several advantages over antibodies. We applied a novel technique for ultrasensitive detection of PA83 using an array of zinc oxide nanorods in conjunction with a FITC‐labeled peptide which showed high affinity with PA. Therefore, the use of zinc oxide nanorods as fluorescence enhancing substrates permitted attomolar detection sensitivity of proteins. However, the peptide to use as diagnostic probe gives a limit which the binding affinities of peptide reactivity lower than that of antibody. Consequently, our research introduced the concept of the polyvalent directed peptide polymer (PDPP). The PDPP will be able to overcome that a peptide has low binding affinity because the multiple peptides in polymer relatively increase to affinity that binding in the various regions as exists with many kind peptides, and as the possible of cooperative binding with diagnostic target. Also, the signal amplification effect will be able to expect which the various peptide diagnostic probes binding in the diagnosis polymer chain. The design of PDPP is now viable alternatives to bio‐diagnostic systems, such as antibodies.