Technologies for monitoring the levels of oxygen has been great importance for biomedical application. Such measurements, especially when performed in real-time, could calculate the rates of cellular metabolism and identify undersupplied regions within tissues and cells. In addition, the O2 is the key metabolite and source of energy cells and is used to produce ATP through the electron transport chain and oxidative phosphorylation process. Therefore, the objective of the present work is to develop an electrochemical oxygen sensor, through the photocatalytic properties of poly(azo-Bismarck) as an alternative strategy for dissolved oxygen sensing. Electrochemical impedance spectroscopy at the polyBBY and polyBBY-AuNP platforms in PBS solution in the absence (0.0 mmol L-1) and presence of O2 (1.25 mmol L-1) revealed that AuNP increases the sensor performance. The ΔZreal (at 0.10 Hz applied) were 6.13 and 18.4 kW to polyBBY and polyBBY-AuNP, respectively. Posteriorly, the polyBBY-AuNP O2 photocatalysis was investigated under LED illumination (monoclonal 5W) in the presence and absence of O2. The EIS analysis based on the circuit equivalent model showed a decrease in the charge transfer resistance (Rtc) to polymer/AuNP interface such as the film/solution interface under illumination at both situations: in the presence and absence of O2. This behavior might be due to oxygen reduction overpotential decrease. On the other hand, the decrease in the oxygen reduction overpotential leads to an increase in the sensor sensibility, as was observed in Fig. 1. Through the relative Zreal values, calculated by |Z0-Zi/Z0|, where Zi is the real impedance in presence of O2 and Z0 is the real impedance in the absence of O2, calibration curves were developed, revealing sensitivity of 0.72 kΩ cm2 L mmol-1 for polyBBY-AuNP without and 1.07 kΩ cm2 L mmol-1 under illumination. The studies revealed the overpotential decrease under illumination, as well as the increase of sensibility. Therefore, the new platform has potential applications for monitoring dissolved oxygen in various environments.

New photochemiresistor dissolved oxygen sensor based on azo-pi-conjugated polymer-gold nanoparticle film

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.