Use of boron-doped nanocrystalline diamond microelectrodes for amperometric determination of serotonin release in human platelets

Introduction

Boron-doped nanocrystalline diamond (BDD) is an outstanding structure, and one of the best materials for high-sensitivity amperometric measurements. Nanocrystalline diamond structures show a high concentration of electrical charge carriers.

Amperometry is a widely used technique for studying the exocytosis of biological amines (dopamine, serotonin, noradrenaline, adrenaline, and histamine), and multielectrode array (MEA) systems have increased the efficiency and speed of amperometric studies.

In human, platelets are the most accessible cells to study the exocytosis of serotonin.

Methods

BDD-MEA fabrication utilizes several processes typical of microelectronics, here including chemical vapor deposition (CVD), optical lithography, metal evaporation, and reactive ion etching (RIE).

We detected amperometric recordings from the quantum release of serotonin from human platelets with boron-doped nanocrystalline diamond on MEA systems (BDD-MEA) of 16 microelectrodes. Our studies were carried out with devices on silicone matrices (BDD-on-silicon MEA)¹ and quartz substrates (BDD-on-quartz MEA)².

Results

Typical amperometric signals were obtained from the release and subsequent oxidation of serotonin molecules stored in platelet vesicles. We carried out and compared the release measurements both under basal conditions and after loading the platelets with 10 µM serotonin for 2 h. In this communication, we show different types of peaks registered in these studies and we present kinetics parameters obtained with both types of MEA systems (maximum oxidation current, spike width at half maximum, spike net charge, and ascending slope of spike).^1,2

Conclusions

BDD MEA devices have proven to be effective and biologically compatible in amperometric studies with live platelets. Here, we demonstrate their usefulness in studies of serotonin exocytosis from human platelets.

References.

¹ González Brito, R; Montenegro, P; Méndez, A; Carabelli, V; Tomagra, G; Shabgahi, R.E.; Pasquarelli, A.; Borges, R. Biosensors2023, 13, 86.

² González Brito, R; Montenegro, P; Méndez, A; Shabgahi, R.E.; Pasquarelli, A.; Borges, R. Biosensors2024, 14, 75.