Abstractly, in this study, an aptasensor is introduced based on a platform consisting of the gold nanorod (AuNR) on a screen printed carbon electrode (SPCE) surface. The aptasensor is applied for detection of the β-casomorphin (BCM-7) as a promising biomarker of autism disorder. The NH2-Apt sequence is directly immobilized onto the AuNR/SPCE surface by formation of a chemisorption bond between the amine-Au groups. By incubation of the BCM-7 onto the aptasensor surface, the aptasensor directed against BCM-7 and cleverly formed a target/Apt complex to produce a measurable electrical current change. The aptasensor shows linearity over the range of 1 fmol L−1 to 25 nmol L−1 with a limit of detection (LOD) of 334 amol L−1. Furthermore, the function of the aptasensor in real samples such as human urine and plasma samples is evaluated. The achieved satisfactory results are mainly due to three main reasons including (1) the large specific surface area of the AuNR which forms a 3D network on the SPCE surface to capture more Apt sequences at the sensing interface, (2) utilizing Apt as the BCM-7 receptor with inherent unique properties to produce a synergetic effect with the AuNR, and finally, (3) effective using screen printing technology with the fantastic capability to less cost of the aptasensor preparation. There is hope that miniaturization of the proposed aptasensor may aid future efforts to detect autism symptoms as early as infancy under clinical conditions in real-world.
