Nguyen, Dinh Cung Tien Thi, Quyen Vu Nguyen, Quynh H. Ko, Jaehyoung Lee, Hoyeon Boudouris, Bryan Jeon, Seung-Yeol Joo, Yongho 2025-05-22T06:31:13Z 2025-05-22T06:31:13Z 2025-05-21 2025-05 https://pubs.kist.re.kr/handle/201004/152496 We demonstrate an enhancement in the figure of merit (mu C*) of a flexible organic electrochemical transistor (OECT) and its dopamine (DA) biosensor by blending various open-shell, non-conjugated radical polymers featuring nitroxide radical active sites as pendant groups with closed-shell, ethylene glycol (EG)-functionalized conjugated polymers as a macromolecular active layer system. The precisely controlled ionic transport of the OECT by the radical polymer modulated the doping level of the EGylated polymer, ensuring well-regulated redox activity and resulting in mu C* values exceeding 192 F V-(1) cm-(1) s-(1), along with an on/off ratio of 104. Additionally, we achieved an ultrasensitive detection limit for DA at the clinically relevant level of 1 pM, along with exceptional specificity, effectively distinguishing DA even in the presence of a substantial excess of interfering substances. These findings underscore the potential of a systematic design approach for developing an advanced, flexible OECT-based biosensor platform through the strategic selection and processing of open- and closed-shell macromolecules. English Nature Publishing Group Engineering flexible dopamine biosensors: blended EGylated conjugated and radical polymers in organic electrochemical transistors Article 10.1038/s41528-025-00412-9 1 npj Flexible Electronics, v.9, no.1 npj Flexible Electronics 9 1 Y scie scopus 001480425400002 2-s2.0-105003940940 Engineering, Electrical & Electronic Materials Science, Multidisciplinary Engineering Materials Science Article STATE FUNDAMENTALS ENERGY-STORAGE CHARGE-TRANSPORT