Newly Developed Electrochemiluminescence Based on Bipolar Electrochemistry for Multiplex Biosensing Applications: A Consolidated Review.

Recently, there has been an upsurge in the extent to which electrochemiluminescence (ECL) working in synergy with bipolar electrochemistry (BPE) is being applied in simple biosensing devices, especially in a clinical setup. The key objective of this particular write-up is to present a consolidated review of ECL-BPE, providing a three-dimensional perspective incorporating its strengths, weaknesses, limitations, and potential applications as a biosensing technique. The review encapsulates critical insights into the latest and novel developments in the field of ECL-BPE, including innovative electrode designs and newly developed, novel luminophores and co-reactants employed in ECL-BPE systems, along with challenges, such as optimization of the interelectrode distance, electrode miniaturization and electrode surface modification for enhancing sensitivity and selectivity. Moreover, this consolidated review will provide an overview of the latest, novel applications and advances made in this field with a bias toward multiplex biosensing based on the past five years of research. The studies reviewed herein, indicate that the technology is rapidly advancing at an outstanding purse and has an immense potential to revolutionize the general field of biosensing. This perspective aims to stimulate innovative ideas and inspire researchers alike to incorporate some elements of ECL-BPE into their studies, thereby steering this field into previously unexplored domains that may lead to unexpected, interesting discoveries. For instance, the application of ECL-BPE in other challenging and complex sample matrices such as hair for bioanalytical purposes is currently an unexplored area. Of great significance, a substantial fraction of the content in this review article is based on content from research articles published between the years 2018 and 2023.

Simultaneous HPLC-APCI-MS/MS quantification of endogenous cannabinoids and glucocorticoids in hair.

Hair matrix could retrospectively record association of endogenous cannabinoids (e.g. 2-arachidonoyl glycerol, 2-AG and N-arachidonoyl-ethanolamine, AEA) and glucocorticoids (e.g. cortisol and cortisone) in a myriad of physiological functions. However, depending on the extraction conditions, the spontaneous isomerization of 2-AG to 1-arachidonoylglycerol (1-AG) and the possible rearrangement of O-arachidonoyl ethanolamine (OAEA) to AEA in various sample matrices could be major obstacles encountered in the detection of both 2-AG and AEA. This study aimed to develop a novel method for simultaneous quantification of 2-AG, AEA, cortisol and cortisone in hair. Methanol was used as the incubation solution and an acidic mixture of deionized water and methanol were utilized as mobile phase in order to avert possible rearrangements of both OAEA and 2-AG. The analyses were performed on a high-performance liquid chromatography tandem mass spectrometer with atmosphere pressure chemical ionization in positive mode. The method showed good linearity in the range of 3.0-250pg/mg for AEA, 15.0-1250pg/mg for 2-AG and 1-250pg/mg for cortisol and cortisone. Limit of detection was 1.5pg/mg for AEA, 6.0pg/mg for 2-AG and 0.5pg/mg for cortisol and cortisone. For all four analytes, intra and inter-day coefficients of variation were less than 20% and recovery above 90%. Population analyses in 473 hair samples established that 2-AG was significantly correlated with AEA. 2-AG was significantly and positively correlated with cortisol and cortisone. There was a significant positive correlation of AEA with cortisol, but not with cortisone. Obese participants showed a significantly higher concentration of cortisone and 2-AG. Males showed significantly higher 2-AG and cortisone levels but significantly lower AEA levels than females.