An impedometric sensor based on boronic acid @ plastic chip electrode for sensitive detection of prostate cancer biomarker spermine

Abstract

Elevated levels of the aliphatic biogenic amine spemine in human urine and plasma has been considered as a biomarker for different types of cancers particularly, prostate cancer (PCa). Rapid measurement of spermine in human body fluids with high sensitivity is of great significance for the early clinical diagnosis of PCa. However, accurate estimation of the change in spermine concentration in the order of sub micromolar level is required for point-of-care testing (POCT) drive. Herein, a spermine specific receptor has been successfully attached onto the surface of a home-made gold modified plastic chip electrode (PCE). This electrosensor showed good repeatability and reproducibility in the electrochemical measurement of spermine when tested via impedance spectroscopy over a wide concentration range 10-3-10-11 M. Attachment of the receptor using gold thiol chemistry has been confirmed by SEM-EDX as well as Raman spectroscopy. The biosensor (i.e. boronic acid fabricated PCE) demonstrated good linearity over a wide concentration window (10−3-10−11 M) with R2 = 0.983, 0.9388, and 0.9454 for aqueous, urine, and blood plasma samples, respectively. The interference studies have also been performed with other biogenic polyamines, which revealed remarkable specificity of the electrosensor for spermine. The ultralow limit of detection (10 pM) undoubtedly reveals the potential of the electrochemical biosensing platform to be useful for POCT applications targeted towards the early diagnosis of PCa.

Keywords

• Biogenic amines
• Biosensing platform
• Composite electrode
• Impedance spectroscopy
• Point-of-care testing