A Photoelectrochemical Sensor for Real-Time Monitoring of Neurochemical Signals in the Brain of Awake Animals

Abstract

Metal ion homeostasis is imperative for normal functioning of the brain. Considering the close association between brain metal ions and various pathological processes in brain diseases, it becomes essential to track their dynamics in awake animals for accurate physiological insights. Although ion-selective microelectrodes (ISMEs) have demonstrated great advantage in recording ion signals in awake animals, their intrinsic potential drift impairs their accuracy in long-term in vivo analysis. This study addresses the challenge by integrating ISMEs with photoelectrochemical (PEC) sensing, presenting an excitation-detection separated PEC platform based on potential regulation of ISMEs. A flexible indium tin oxide (Flex-ITO) electrode, modified with MoS 2 nanosheets and Au NPs, serves as the photoelectrode and is integrated with a micro-LED. The integrated photoelectrode is placed on the rat skull to remain unaffected by animal activity. The potential of ISME dependent on the concentration of target K + serves as the modulator of the photocurrent signal of the photoelectrode. The proposed design allows deep brain detection while minimizing interference with neurons, thus enabling real-time monitoring of neurochemical signals in awake animals. It successfully monitors changes in extracellular K + levels in the rat brain after exposure to PM2.5, presenting a valuable analytical tool for understanding the impact of environmental factors on the nervous system.

P-EcStat: A Versatile Design of Photoelectrochemical and Electrochemical Sensing System with Smartphone Interface via Bluetooth Low Energy

“…Research efforts in these fields are mainly directed towards diversifying sensor materials, utilizing different types and structural forms of nanomaterials with or without labels to enhance identification performance, sensitivity, and specificity in the analysis of interest [1][2][3][4][5][6][7][8][9][10][11]. Consequently, EC and PEC sensors have become powerful tools in analytical chemistry, offering broad applicability in diverse fields such as food safety [5,[12][13][14][15][16][17][18], environmental monitoring [18][19][20][21][22][23], and health diagnostics [3,18,[24][25][26][27][28][29][30][31][32][33][34]. EC sensors function by using receptors immobilized on the surface of the electrode.…”