Ultrasensitive detection of aromatic water pollutants through protein immobilization driven organic electrochemical transistors Subhankar Sahu a , Lokesh Kumar b , Sumita Das a , Dipti Gupta b** , and Ruchi Anand a* a Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Maharashtra, 400076, India, b Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, Maharashtra, 400076, India Access to clean water is indispensable for maintaining a healthy ecosystem as it is the key element for the survival and sustenance of life. In such context,declining water quality owing to the amassing of toxic aromatic pollutants (benzene, phenol, xylenols etc.) has been considered as a growing potential threat to environmental sustainability [1] . Rapid, economic and reliable detection of such xenobiotics has also remained a daunting task due to the lack of suitable detectable functional groups. However, proteins possessing natural sensing mechanisms perfected through eons of nature’s evolutionary optimization seem to have addressed the problem [2] . Herein, we have demonstrated the ultrasensitive phenol detection mechanism of the biosensing protein MopR. Initially, a strip-based biosensor capable of tracking down phenol till ~10 ppb (0.1 µM) in water was explored using graphene oxide (GO) [3] nanosheets as an immobilization matrix. Taking the sensor design one step further, we have developed an organic electrochemical transistor (OECT) [4] based device capable of detecting phenol till ~2 ppb (0.02 µM) by employing GO as gate electrode modification substrate for protein immobilization. MopR protein immobilized gate electrode is used as the sensing module in the OECT to probe the phenol concentration in the water samples. The OECT uses PEDOT:PSS as an organic semiconductor material due to its high transconductance and biocompatibility and is capable of detecting phenol even in mixture samples crowded with other non-targeted analytes.Considering the fact that only 3% of all the available water is portable, the global demand of safe drinking water is on rise. In such context, our research sits at the conjunction of environmental sustainability and human health proving a fast, efficient and reliable OECT platform for aromatic pollutants monitoring.
References 1. S. Sahu, R. Roy, R. Anand, ACS Sensors 2022, 7, 704.
2. S. Ray, M. J. Gunzburg, M. Wilce, S. Panjikar, R. Anand, ACS Chem. Biol. 2016, 11, 2357. 3. J. Zhang, J. Zhang, F. Zhang, H. Yang, X. Huang, H. Liu, S. Guo, Langmuir 2010, 26, 6083. 4. J. Rivnay, S. Inal, A. Salleo, R. M. Owens, M. Berggren, G. G. Malliaras, Nat. Rev. Mater. 2018, 3.
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