Quantification of Tyrosine in Pharmaceuticals with the New Biosensor Based on Laccase-Modified Polypyrrole Polymeric Thin Film.

Ancuța Dinu,Constantin Apetrei

doi:10.3390/polym14030441

Ancuța Dinu, Constantin Apetrei

Open Access

https://doi.org/10.3390/polym14030441

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Journal: Polymers	Publication Date: Jan 22, 2022
Citations: 8	License type: CC BY 4.0

Affiliation: "Dunarea de Jos" University of Galati

Abstract

Stress, a state of body tension, sometimes caused by increased levels of tyrosine (Tyr) in the body, can lead to serious illnesses such as depression, irritability, anxiety, damage to the thyroid gland, and insomnia. The body can be provided with an adequate concentration of tyrosine by taking pharmaceutical products or by dietary intake. Therefore, this study presents the development of a new enzyme sensor for the quantification of Tyr in pharmaceuticals. A screen-printed carbon electrode (SPCE) was modified with the conductive polymer (CP) polypyrrole (PPy) doped with hexacyanoferrate (II) anion (FeCN), the polymer having been selected for its excellent properties, namely, permeability, conductivity, and stability. The enzyme laccase (Lacc) was subsequently immobilized in the polymer matrix and cross-linked with glutaraldehyde, as this enzyme is a thermostable catalyst, greatly improving the performance of the biosensor. The electrochemical method of analysis of the new device, Lacc/PPy/FeCN/SPCE, was cyclic voltammetry (CV), and chronoamperometry (CA) contributed to the study of changes in the biosensor with doped PPy. CV measurements confirmed that the Lacc/PPy/FeCN/SPCE biosensor is a sensitive and efficient platform for Tyr detection. Thus, this enzyme sensor showed a very low limit of detection (LOD) of 2.29 × 10−8 M, a limit of quantification (LOQ) of 7.63 × 10−8 M, and a very high sensitivity compared to both devices reported in the literature and the PPy/FeCN/SPCE sensor. Quantitative determination in pharmaceuticals was performed in L-Tyr solution of different concentrations ranging from 0.09 to 7 × 10−6 M. Validation of the device was performed by infrared spectrometry (FT-IR) on three pharmaceuticals from different manufacturers and with different Tyr concentrations.

Highlights

Electrochemical biosensors, designated by scientific researchers as modern analytical devices for the detection of various organic or inorganic compounds, facilitate the performance of many activities in everyday life, activities that require financial efforts, time, and inefficiency [1,2]
Same authors in which the PPy/FeCN/screen-printed carbon electrode (SPCE) sensor was fabricated [20], this section will highlight the importance of the Lacc enzyme in the detection of Tyr in pharmaceuticals, the performance of the new biosensor compared to the sensor
A new biosensor was developed by immobilizing the laccase enzyme on the surface of an electrode modified with a conductive material with excellent properties, PPy polymer doped with FeCN anion, by chronoamperometry

Summary

Introduction

Electrochemical biosensors, designated by scientific researchers as modern analytical devices for the detection of various organic or inorganic compounds, facilitate the performance of many activities in everyday life, activities that require financial efforts, time, and inefficiency [1,2]. The detection of L-Tyr in pharmaceuticals is of great importance for the quality control of pharmaceutical products, in the monitoring of the stability of the pharmaceuticals during storage, and in studies regarding interaction with other active compounds or excipients. The essence of a biosensor is to convert the biological response into an electrical signal, and to manufacture it, materials such as enzymes, antibodies, and nucleic acids are used, which requires multidisciplinary research in chemistry, medicine, pharmacy, biology, and engineering [3,4]. Sponse into an electrical signal, and to manufacture it, materials such as enzym bodies, and nucleic acids are used, which requires multidisciplinary research in try, medicine, pharmacy, biology, and engineering [3,4]. One of the reasons for the present investigation is stress, which is an unav partOne of of human existence and which can take extreme causing part numerous the reasons for the present investigation is stress, which forms, is an unavoidable of human existence and which can take extreme forms, causing numerous mental disorders disorders such as depression, anxiety, schizophrenia, post-traumatic stress d such as depression, anxiety, schizophrenia, post-traumatic stress disorder, sleep disorders, sleep disorders, and thyroid disorders [5,6,7]

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