Determination of sitagliptin in human plasma using a smart electrochemical sensor based on electroactive molecularly imprinted nanoparticles

Isma Haq; Kaseb Alanazi; Joanna Czulak; Sabrina Di Masi; Elena Piletska; Adnan Mujahid; Tajamal Hussain; Sergey A Piletsky; Alvaro Garcia-Cruz

doi:10.1039/d1na00194a

Determination of sitagliptin in human plasma using a smart electrochemical sensor based on electroactive molecularly imprinted nanoparticles

Nanoscale Adv. 2021 May 28;3(14):4276-4285. doi: 10.1039/d1na00194a. eCollection 2021 Jul 13.

Authors

Isma Haq¹, Kaseb Alanazi², Joanna Czulak³, Sabrina Di Masi⁴, Elena Piletska², Adnan Mujahid¹, Tajamal Hussain¹, Sergey A Piletsky², Alvaro Garcia-Cruz²

Affiliations

¹ Institute of Chemistry, University of the Punjab Quaid-e-Azam Campus Lahore Pakistan.
² Department of Chemistry, University of Leicester University Rd Leicester LE1 7RH UK agc14@leicester.ac.uk.
³ MIP Diagnostics Ltd Colworth Science Park, Sharnbrook Bedford MK44 1LQ UK.
⁴ Department of Biological and Environmental Sciences and Technologies, University of Salento Via Monteroni Lecce IT 73100 Italy.

Abstract

Sitagliptin is a hypoglycaemic agent used to reduce blood sugar levels in patients with type 2 diabetes mellitus (T2DM). Real time monitoring of sitagliptin levels is crucial to prevent overdose, which might cause liver, kidney and pancreatic diseases. As an alternative solution, a sitagliptin voltammetric sensor was fabricated using artificial receptors called electroactive molecularly imprinted polymer nanoparticles (nanoMIPs). The nanoMIP tagged with a redox probe (ferrocene) combines both the recognition and reporting functions. Traditional electrochemical sensors determine the redox activity of an analyte. Thus, they are influenced by interfering molecules and the nature of the sample. These innovative nanoMIPs allow us to easily design and customise sensors, increase their sensitivity and minimise the cross reactivity in biological samples. The present technology replaces the traditional enzyme-mediator pairs used in traditional biosensors. The polymer composition was optimized "in silico" using docking and screening methods. Nanoparticles were synthesized via free radical polymerization and a solid phase method and then characterized by infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The specific sitagliptin nanoparticles were covalently immobilized on platinum electrodes via silane and carbodiimide chemistry. The determination of sitagliptin in human plasma by a nanoMIP sensor was assessed by differential pulse voltammetry (DPV). The sensor current response was directly related to the change in nanoMIP conformation triggered by the analyte. The optimisation of the sensor response was made by adjusting (i) the silane concentration, (ii) nanoMIP concentration, and (iii) immobilization time. The sensor measurements in plasma revealed high selectivity and a sensitivity of 32.5 ± 0.6 nA pM^-1 towards sitagliptin, and the limit of detection of the fabricated sensor was found to be 0.06 pM. The sensor displayed a satisfactory performance for the determination of sitagliptin in spiked human plasma, demonstrating the potential of this technology for drug monitoring and clinical diagnosis.