Orientation of llama antibodies strongly increases sensitivity of biosensors

Biosens Bioelectron. 2014 Oct 15:60:130-6. doi: 10.1016/j.bios.2014.04.017. Epub 2014 Apr 18.

Abstract

Sensitivity of biosensors depends on the orientation of bio-receptors on the sensor surface. The objective of this study was to organize bio-receptors on surfaces in a way that their analyte binding site is exposed to the analyte solution. VHH proteins recognizing foot-and-mouth disease virus (FMDV) were used for making biosensors, and azides were introduced in the VHH to function as bioorthogonal reactive groups. The importance of the orientation of bio-receptors was addressed by comparing sensors with randomly oriented VHH (with multiple exposed azide groups) to sensors with uniformly oriented VHH (with only a single azide group). A surface plasmon resonance (SPR) chip exposing cyclooctyne was reacted to azide functionalized VHH domains, using click chemistry. Comparison between randomly and uniformly oriented bio-receptors showed up to 800-fold increase in biosensor sensitivity. This technique may increase the containment of infectious diseases such as FMDV as its strongly enhanced sensitivity may facilitate early diagnostics.

Keywords: Foot-and-mouth disease virus; Llama heavy-chain antibodies; Orientation; Site-specific azide incorporation; Surface plasmon resonance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral / immunology*
  • Biosensing Techniques / instrumentation*
  • Camelids, New World / immunology*
  • Equipment Design
  • Equipment Failure Analysis
  • Foot-and-Mouth Disease Virus / immunology*
  • Foot-and-Mouth Disease Virus / isolation & purification*
  • Immunoassay / instrumentation*
  • Protein Conformation
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Surface Plasmon Resonance / instrumentation*

Substances

  • Antibodies, Viral