Detection of microalgae single-cell antioxidant and electrochemical potentials by gold microelectrode and Raman micro-spectroscopy combined with chemometrics

Abstract

Microalgae single-cell electrochemical characteristics are playing an important key role in its industrial application and functionality. This study conducted a single-cell electrochemical study to explain the influence mechanism of intracellular phenolic and flavonoid contents of microalgae on its surface electric charge. In the method, four microalgae species, Arthrospira platensis (AP), Chlorella vulgaris (CV), Phaeodactylum tricornutum (PT), and Scenedesmus obliquus (SO), were studied through single-cell electrochemical current (SCC), single-cell micro-Raman spectrometry (SCMR), and other physicochemical methods. Also, they were correlated with the chemical analytical methods. In the results, PT and AP phenolics, flavonoids, and antioxidant activities were significantly high compared to CV and SO. On the other hand, SO had the highest SCC compared to AP and PT. Also, SCMR at 1514 cm−1 was negatively correlated with antioxidant activity by nitric oxide (r2 = -0.80). In conclusion, single-cell current measurement by gold microelectrode can verify the antioxidant activity of the different microalgae species. Besides, this work provides a simple micro-level study of the single-cell phytochemicals to better explain their exact functional impacts compared to the methods of macro-analyses that use millions of cells, which reduces their sensitivity. In which, it can be applied in the real-time functionality evaluation during microalgae cultivation.