A chelating-bond breaking and re-linking technique for rapid re-immobilization of immune micro-sensors

Biomed Microdevices. 2012 Apr;14(2):303-11. doi: 10.1007/s10544-011-9607-6.

Abstract

With high sensitivity and specificity to antigen, immune micro-sensors can be used in rapid detection of pathogenic microbial. This study proposes and develops a method for rapidly regeneration of antibody on a resonant micro-cantilever sensor. A nitrilotriacetic acid (NTA) derivative is synthesized with cystine and bromoacetic acid, then added with 2-mercaptoethanol to prepare a mixed self-assembled monolayer (SAM) on Au (111) surface of the cantilever. Ni²⁺ ions are thereafter chelated on the mixed SAM to form a breakable and re-linkable chelating-bond layer. Repeatable cycles of antibody immobilization and erasing are experimentally validated with a detectable marker of synthesized biotinylated poly peptides harboring six histidine residues (named as His-Bio). Two distinguished pathogenic microbial, Escherichia. coli O157:H7 and Bacillus Anthracis, are detected with the rapidly regenerated sensor. The E. coli O157:H7 sensor exhibits a three-time repeated detection to the 10³ CFU/ml concentration microbial. Then, an E. coli O157:H7 sensor is eluted with Tris-HCl (20 mM Tris, 150 mM NaCl, 0.1% Tween 20, pH = 3.0) and rapidly reconstructed into a B. Anthracis sensor by changing the re-immobilized antibody. The cantilever sensor no longer responses to E. coli O157:H7 even in a high concentration of 10⁷ CFU/ml. In contrast, the sensor is experimentally confirmed being resoluble to low concentration B. Anthracis at 10³ spores/ml level. The proposed fast regeneration method is promising in repeatedly or multi-target detection applications of micro/nano immune-sensors, e.g. the resonant micro-cantilevers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / chemistry
  • Antibodies
  • Antibodies, Bacterial / immunology*
  • Antibodies, Immobilized / metabolism
  • Bacillus anthracis / isolation & purification
  • Biosensing Techniques / instrumentation*
  • Biosensing Techniques / methods*
  • Cystine / chemistry
  • Equipment Design
  • Escherichia coli O157 / isolation & purification
  • Immunoassay / methods
  • Mercaptoethanol / chemistry
  • Micro-Electrical-Mechanical Systems / instrumentation
  • Micro-Electrical-Mechanical Systems / methods
  • Nitrilotriacetic Acid / chemical synthesis
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Silicon Dioxide / metabolism

Substances

  • Acetates
  • Antibodies
  • Antibodies, Bacterial
  • Antibodies, Immobilized
  • Cystine
  • Mercaptoethanol
  • bromoacetate
  • Silicon Dioxide
  • Nitrilotriacetic Acid