Electrochemical Dopamine Biosensor Based on Poly(3-aminobenzylamine) Layer-by-Layer Self-Assembled Multilayer Thin Film.

Tayanee Panapimonlawat,Saengrawee Sriwichai,Sukon Phanichphant

doi:10.3390/polym13091488

Abstract

Dopamine (DA) is an important neurotransmitter which indicates the risk of several neurological diseases. The selective determination with low detection limit is necessary for early diagnosis and prevention of neurological diseases associated with abnormal concentration of DA. The purpose of this study is to fabricate a poly(3-aminobenzylamine)/poly(sodium 4-styrenesulfonate) (PABA/PSS) multilayer thin film for use as an electrochemical DA biosensor. The PABA was firstly synthesized using a chemical oxidation method of 3-aminobenzylamine (ABA) monomer with ammonium persulfate (APS) as an oxidant. For electrochemical biosensor, the PABA/PSS thin film was fabricated on fluorine doped tin oxide (FTO)-coated glass substrate using the layer-by-layer (LBL) self-assembly method. The optimized number of bilayers was achieved using SEM and cyclic voltammetry (CV) results. The electroactivity of the optimized LBL thin film toward detection of DA in neutral solution was studied by CV and amperometry. The PABA/PSS thin film showed good sensitivity for DA sensing with sensitivity of 6.922 nA·cm−2·µM−1 and linear range of 0.1–1.0 µM (R2 = 0.9934), with low detection limit of 0.0628 µM, long-term stability and good reproducibility. In addition, the selectivity of the PABA/PSS thin film for detection of DA under the common interferences (i.e., ascorbic acid, uric acid and glucose) was also presented. The prepared PABA/PSS thin film showed the powerful efficiency for future use as DA biosensor in real sample analysis.

Highlights

After 30 days, the current response of the PABA/poly(sodium 4styrenesulfonate) (PSS) electrodes retained about 74% of the initial response. These results indicated that the fabricated DA biosensor based on the PABA/PSS self-assembled multilayers would be able to detect low levels of DA concentrations with good selectivity and stability, which will be useful for clinical diagnosis applications in the future
The electrochemical biosensor based on PABA self-assembled multilayers for the detection of DA was successfully developed using the LBL self-assembly method
For building up the biosensor, the cyclic voltammetry (CV) measurements showed that the 12 bilayers was the optimum loading number for the PABA/PSS thin film, with maximum electric charge (Q)

Summary

Introduction

DA levels affect the human brain functions in transmitting electrical signals, hormonal, emotional, metabolic, renal and play an important role in immune and cardiovascular systems [1,2]. The normal DA concentration in human blood is in the range 0.01–1 μM [3,4]. The extremely low levels of dopamine increase the risk of neurological diseases such as Parkinson’s disease, Schizophrenia, Tourette’s syndrome, Alzheimer’s disease, Huntington’s disease, hypertension and attention deficit hyperactivity disorder [4,5,6]. It is; necessary to detect DA in low concentrations

Objectives

Results

Conclusion