Surface Plasmon Resonance (SPR) Biosensors for Specific Detection of Neonicotinoids

Surface Plasmon Resonance (SPR) Biosensors for Specific Detection of Neonicotinoids

Neonicotinoids such as thiacloprid and imidacloprid are a class of pesticides which are able to block nicotinic acetylcholine receptors in the central nervous system of insects. In this presentation, we first introduced two highly specific oligopeptide sequences RKRIRRMMPRPS (P₁) and RNRHTHLRTRPR (P₂) as biomolecular receptors for binding neonicotinoids such as thiacloprid and imidacloprid. These two oligopeptides were identified after 3 rounds of panning processes by using phage display library. The former oligopeptide P₁ shows high affinity for thiacloprid whereas the latter oligopeptide P₂ shows high affinity for imidacloprid. By immobilizing these two oligopeptides on SPR sensor chips, we successfully prepared a biosensor system for on-line monitoring of either thiacloprid or imidacloprid in buffer solutions. Our SPR experiments confirm the strong binding thiacloprid and imidacloprid to surface immobilized oligopeptides. The limit of detection for thiacloprid and imidacloprid is approximately 2μM.  Surprisingly, despite the similarity of thiacloprid and imidacloprid, cross-binding is minimal. Experimental results for analyzing neonicotinoids on fruits and vegetable samples will also be discussed in this presentation.