The P2X purinoceptor 3 (P2X3) plays a crucial role in signalling leading to chronic inflammatory pain and, thus, the P2X3 receptor provides a proven target for its treatment. Botulinum toxin type A (BoNT/A) is a potentially promising candidate drug for use in this situation. Long-acting botulinum neurotoxin type D (BoNT/D) inhibits inflammatory pain peptide release from cultured sensory neurons evoked by K+, bradykinin or capsaicin. The purpose of this project is to develop single-chain antibody variable fragments (scFv) recognising extracellular domains of P2X3, for use as a targeting agent to deliver protease and translocation domains of BoNT/A and BoNT/D (LC-HN/A and LC-HN/D) to pain-signalling neurons. A rabbit scFv library was generated, and phage display was applied for anti-P2X3 scFv recombinant antibody selection. After five rounds of bio-panning, followed by polyclonal phage ELISA, monoclonal ELISA, cross reactivity analysis, competitive ELISA, western blotting and immunofluorescence staining, anti-P2X3-257 scFv clones with high specificity and affinity were successfully selected. The scFv gene was fused to BoNT/A and BoNT/D and expressed as a fusion protein in E. coli. After purification,this protein was shown to enter sensory neurons and to cleave its neuronal target, VAMP2. The efficacy of this therapeutic will be further evaluated using established capsaicin-induced or formalin-induced rat inflammatory pain models.