Single-domain antibody based thermally stable electrochemical immunosensor

Biosens Bioelectron. 2016 Sep 15;83:162-8. doi: 10.1016/j.bios.2016.04.054. Epub 2016 Apr 19.

Abstract

Conventional monoclonal and polyclonal antibodies are sensitive to changes in environmental factors such as temperature, pH, humidity, etc. This limits the current cost-effective and portable electrochemical immunosensors in harsh environments. Using Ricin Chain-A, a naturally occurring toxin, as a model analyte we report fabrication of a thermally stable electrochemical immunosensor. Single-domain antibodies (sdAb) or nanobodies have been employed as recognition elements for direct detection of Ricin at temperatures great than 4°C. Immunosensor fabricated using the conventional Ricin monoclonal and polyclonal antibodies have also been demonstrated for comparison. In the case of sdAb immunosensor, Ricin was detected in a linear range of 1log(fg/mL)-1log(μg/mL) with a sensitivity of 0.07μA/log(g/mL)/cm(2) using cyclic voltammetry. The fabricated miniaturized sensors have demonstrated higher shelf life and stability at temperatures up to 40°C. Therefore these electrochemical sensors can be integrated as a part of a portable device for point-of-care immunosensing.

Keywords: Electrochemical sensor; Immunosensor; Ricin; Single-domain antibody; Thermal-stability.

MeSH terms

  • Antibodies, Immobilized / chemistry
  • Biosensing Techniques / instrumentation
  • Chemical Warfare Agents / analysis*
  • Electrochemical Techniques / instrumentation*
  • Equipment Design
  • Immunoassay / instrumentation*
  • Point-of-Care Systems
  • Protein Stability
  • Ricin / analysis*
  • Single-Domain Antibodies / chemistry*
  • Temperature

Substances

  • Antibodies, Immobilized
  • Chemical Warfare Agents
  • Single-Domain Antibodies
  • Ricin