Harnessing Photocathodic and Nanozymatic Synergies of Graphene Oxide Frameworks for Enhanced Organic Photoelectrochemical Transistor Bioanalysis

While existing graphene oxide frameworks (GOF) are extensively studied in various energy devices, no effort has been made to explore their potentials in organic photoelectrochemical transistor (OPECT) bioanalysis. Here, we introduce a GOF-gated OPECT, where the photocathodic and nanozymatic synergies of a layered porphyrin (Fe)-cross-linked GOF are synergistically harnessed to achieve enhanced-mode OPECT bioanalysis. The peroxidase-mimicking and photocathodic-responding properties of the as-prepared GOF could not only trigger the biomimetic precipitation (BMP) but also enable the photogating of a polyethylenimine-dedoped PEDOT:PSS channel. Linking with a magnetic separation-assisted hybridization chain reaction amplification correlating the target microRNA-17, the BMP could severely block its layered structure, consequently inducing the inhibition of interfacial charge and mass transfer and thus a pronounced gating effect. The good analytical performance of the developed OPECT bioanalysis is validated by experiments with a detection limit as low as 1 fM. This study demonstrates the potential of GOF in OPECT bioanalysis. Considering the large family of functional GOF, its implications are expected in OPECT.