Gold-modified laser-scribed lettuce-like graphene electrodes for ultrasensitive detection of bioactive molecules

Detecting low levels of bioactive molecule residues is important for monitoring the pharmacokinetics, pharmacovigilance and assessing the environmental impact of drug residues in water bodies. In this paper, we report a straightforward method for building laser-scribed lettuce-like porous graphene electrodes (LSGEs) by employing direct laser writing on a polyimide (PI) substrate. To improve their electrochemical performance, the LSGEs were decorated with gold nanoparticles (AuNPs/LSGEs), showing that the introduction of AuNPs procured substantial enhancements in terms of heterogeneous electron transfer rate (k0) and electrochemical active surface area, as assessed using 1,1-ferrocenedimethanol as a redox probe molecule. The gold-modified lettuce-like porous graphene electrodes can accurately detect paracetamol (PCM), as a model drug, even in the presence of diverse potential interfering drug molecules such as uric acid or dopamine. The AuNPs/LSGEs can sense paracetamol throughout a linear range of 5 to 2000 nM with a detection limit as low as 3.39 nM. Furthermore, the AuNPs/LSGEs can detect PCM in diluted human blood serum as a complex matrix, demonstrating their reliability in complex matrices. Thus, the laser-scribed graphene electrodes hold significant promise for robust and sensitive detection of drug molecules.