Glutaraldehyde functionalized reduced graphene oxide based resistive sensors for detection of PCA3

Prostate cancer antigen 3 (PCA3) has emerged as a critical biomarker for the early detection of prostate cancer, complementing the traditional prostate-specific antigen (PSA) testing. This research presents a novel resistive sensor based on reduced graphene oxide (RGO) functionalized with glutaraldehyde (GA)/complementary single-stranded DNA (ss-DNA) for the detection of the PCA3 RNA. The device was meticulously characterized at each fabrication step to confirm the successful integration of the various layers on the sensor device, utilizing atomic force microscopy (AFM) which confirmed the increase in the thickness of the sensor from ∼1.4 nm (only RGO) to ∼25 nm for the RGO-GA/ss-DNA/PCA3 device. Field emission scanning electron microscopy exhibited a change in the surface morphology after each step of device fabrication and testing. Fourier-transform infrared (FTIR) spectroscopy was conducted to confirm the presence of functional groups in each component of the sensor. The fabricated resistive sensor demonstrated mean response ranging from 1.203 to 59.44% for 0.1 to 100 ng mL^-1 PCA3 RNA. Notably, the device exhibited stability over a period of two weeks and displayed high selectivity for PCA3. The developed RGO-GA/ss-DNA/PCA3 sensor was tested with RNA extracted from multiple prostate cancer cell lines and other cancer cell lines and demonstrated response only to RNA extracted from LNCaP as it was the only cell line expression of PCA3. The findings from the developed sensor were cross-validated with the observations of a semi quantitative polymerase chain reaction (qPCR), and were found to be closely matched.