NanoMIP based optical sensor for pharmaceuticals monitoring

• NanoMIPs were produced for target pharmaceutical.
• MIPs capable of capturing target pharmaceutical diclofenac specifically.
• A novel optical based sensor was developed for affinity based diclofenac assays.
• LC–MS analysis confirmed high affinity results of the sensor.
• A long shelf life was found for MIPs to capture its target.

Nanoparticles synthesised using molecular imprinting (MIP) with high affinity for diclofenac were produced and applied in the development of an optical sensor based on surface plasmon resonance (SPR). MIPs were synthesised with diclofenac as the template using solid-phase synthesis with photopolymerisation, a method which allows the template to be reused successfully. Particle size of ∼132.3 nm ± 3.2 was achieved with low polydispersity index (0.1), which confirms the quality of the synthesised nanoMIPs. The MIPs were then immobilised on the surface of the SPR-2 gold sensor chips via covalent coupling using EDC/NHS. An affinity based-diclofenac assay was then constructed on the surface of the sensor. The diclofenac drug was then successfully detected in the concentration range of 1.24–80 ng mL−1. The nanoMIP sensor surfaces were then regenerated using glycine–hydrochloric acid solution and reused for subsequent analysis indicating the stability of the sensor surface. Kinetic data analysis indicated a dissociation constant of 1.48 × 10−9 M was achieved. Cross reactivity studies were conducted against other pharmaceuticals using the developed sensor. The nanoMIP affinity towards diclofenac was also confirmed by eluting a diclofenac solution through a solid phase–nanoMIP columns (SPE) and analysing the eluents using an LC–MS. The developed SPR sensor with the nanoMIP showed good potential for using the technology for the capture and detection of diclofenac in water.