Laser-scribed graphene sensor based on gold nanostructures and molecularly imprinted polymers: Application for Her-2 cancer biomarker detection

Abstract Laser scribed graphene (LSG) has shown great potential as a sensing platform due to its high sensitivity, simplicity, porosity, and flexibility. In this context, we report a novel biosensing platform that utilizes LSG electrodes modified with nanostructured gold and molecularly imprinted polymer (MIP) to enhance its sensitivity and selectivity. This biomimetic sensing platform is used to detect the human epidermal growth factor receptor 2 (Her-2) protein, a significant breast cancer biomarker. Hence, a simple and accurate biomimetic sensor is developed in this study. To the best of our knowledge, this is the first report on nanostructured gold modified MIP-based LSG sensor for Her-2. LSG electrodes are fabricated by irradiation of a polyimide sheet using a CO2 laser. Nanostructured gold is electrodeposited onto the LSG to enhance its sensitivity and facilitate better Her-2 immobilization on the sensor surface. For MIP preparation, 3, 4-ethylenedioxythiophene (EDOT) was electropolymerized after pre-adsorption of Her-2 on the electrode surface for 20 min. The MIP deposition, removal, and adsorption parameters were investigated and optimized. The developed sensing strategy showed an excellent ability to detect Her-2 in the concentration range from 1 to 200 ng/mL with a LOD of 0.43 ng/mL. The biomimetic sensor showed high selectivity towards the detection of Her-2 in the presence of other interfering molecules and appreciable recovery values of Her-2 in the spiked undiluted human serum samples. Finally, to show the potential application of the developed LSG-AuNS-MIP sensor as a point-of-care device, the sensor is integrated with a homemade open-source electrochemical analyzer KAUSTat to detect Her-2.